Why is an EV\'s backup power less than it\'s driving power?...

[Ricky]

On Thursday, November 17, 2022 at 10:47:56 PM UTC-5, Fred Bloggs wrote:

On Thursday, November 17, 2022 at 8:18:50 PM UTC-5, Ed Lee wrote:
On Thursday, November 17, 2022 at 5:00:38 PM UTC-8, Fred Bloggs wrote:
On Thursday, November 17, 2022 at 3:58:36 PM UTC-5, John Larkin wrote:
On Thu, 17 Nov 2022 10:32:33 -0800 (PST), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

On Thursday, November 17, 2022 at 10:30:31 AM UTC-5, John Larkin wrote:
On Thu, 17 Nov 2022 05:03:57 -0800 (PST), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

On Thursday, November 17, 2022 at 4:27:46 AM UTC-5, Commander Kinsey wrote:
If an EV has an output power of say 80kW to drive the motors when driving, why is the backup power (to power your house in a power outage) only about 10kW? It\'s the same battery!

And why do people say it costs thousands of dollars to fit something to do this? Surely a 10kW invertor doesn\'t cost much, just something to make 400VDC into 240VAC. I\'d say more like 500 dollars.

You need to learn the difference between energy and power. The 80kW is really 80kWh(hours), a measure of energy stored in the battery. The 10kW is a measure of power which is the rate of energy extraction from the battery, usually specified in kW, kilo-watts, thousands of Watts. There is no logical connection between the two ratings. The engineering requirements of the battery EV application determines that.

He clearly said that the battery can deliver 80 KW of power. No 80 KWH
car is going to be limited to 10 KW into the motors. Ecars are all
about acceleration.

That 80kW is quoted quite often as the battery capacity when they mean 80kWh of course. Without that as his fundamental misunderstanding, the question is senseless.
The misunderstanding was yours. The nastiness too.
I have no misunderstanding. The manufacturers don\'t specify the \"drive power\" of the batteries in their EV. Why would the consumer need to know that? They do specify battery capacity of their EV because it gives the consumer an idea of expected range.
3 miles per kwhr is a good rule of thumb. So, if you need to drive 60MPH, then you need around 20kW drive power. I don\'t know why people need 150kW, unless they are driving 450MPH.

The OP is clearly confusing battery capacity with \"drive power.\"

That big Ford truck only puts out 2.4kW with its V2H bidirectional charger, with plans to maybe introduce one with 9.6kW sometime in the future. And even the small one adds thousands to the price of the vehicle. They\'re not going to waste a bunch of money making something people won\'t buy in the volume necessary to make a profit.

The question made sense. Why a 10 KW inverter? The answer is probably,
it\'s enough for a house backup and a bigger inverter would cost more.
That Ford thing wouldn\'t even turn over a 2 ton a/c. Looks like they just gave up powering the big stuff. Looks like they\'re going for 30 hours continuous at rated backup peak and the homeowner can take if from there, settling for less or more, it\'s up to them how they load or unload it.

Battery cooling could be involved too, for a parked car.
Do batteries get all that hot in discharge?
Yes if you are discharging 50A. 20kW is around 50A @ 400V.
We\'re talking about a textbook discharge condition in the V2H home backup situation. The only dissipation mechanism I see outright is the I^2R loss in the battery internal resistance- and that should be ultra-minimized. Driving is a different story. Don\'t those electric motors constantly alternate between loading the battery and generating power from forward mechanical motion to recharge the battery? Charging the battery is a super-high power dissipation: battery terminal voltage x charging current (into the battery). Ideally discharge current that only leaves the battery causes zero power dissipation in the battery.

??? The power of the battery voltage and current is either input to the battery for charging, or it\'s the power out to the circuit. The only dissipation would be losses which are very similar between charge and discharge. There are ohmic losses in the conductors in the battery, but there\'s also some loss in the chemistry, in that it requires diffusion. At higher currents the diffusion does not keep up as well as it might and the battery appears to have some extra losses.

There is zero reason to think that there are no losses on discharge. But there\'s no good way to measure the actual energy in the battery, so the losses on charge and discharge are hard to separate. I suppose you can consider the energy to be the useful coulombs in the battery, times the open circuit voltage. The voltage while discharging will be lowered by the net losses of discharge, in a similar manner to how the voltage when charging will be higher than the open circuit voltage, so that increase represents the losses of charging.

It is certainly not reasonable to consider that the conductors have losses in charging and none when discharging.

--

Rick C.

++- Get 1,000 miles of free Supercharging
++- Tesla referral code - https://ts.la/richard11209

 

[Ricky]

On Thursday, November 17, 2022 at 10:57:43 PM UTC-5, Fred Bloggs wrote:

On Thursday, November 17, 2022 at 8:27:56 PM UTC-5, Ricky wrote:
On Thursday, November 17, 2022 at 8:00:38 PM UTC-5, Fred Bloggs wrote:
On Thursday, November 17, 2022 at 3:58:36 PM UTC-5, John Larkin wrote:
On Thu, 17 Nov 2022 10:32:33 -0800 (PST), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

On Thursday, November 17, 2022 at 10:30:31 AM UTC-5, John Larkin wrote:
On Thu, 17 Nov 2022 05:03:57 -0800 (PST), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

On Thursday, November 17, 2022 at 4:27:46 AM UTC-5, Commander Kinsey wrote:
If an EV has an output power of say 80kW to drive the motors when driving, why is the backup power (to power your house in a power outage) only about 10kW? It\'s the same battery!

And why do people say it costs thousands of dollars to fit something to do this? Surely a 10kW invertor doesn\'t cost much, just something to make 400VDC into 240VAC. I\'d say more like 500 dollars.

You need to learn the difference between energy and power. The 80kW is really 80kWh(hours), a measure of energy stored in the battery. The 10kW is a measure of power which is the rate of energy extraction from the battery, usually specified in kW, kilo-watts, thousands of Watts. There is no logical connection between the two ratings. The engineering requirements of the battery EV application determines that.

He clearly said that the battery can deliver 80 KW of power. No 80 KWH
car is going to be limited to 10 KW into the motors. Ecars are all
about acceleration.

That 80kW is quoted quite often as the battery capacity when they mean 80kWh of course. Without that as his fundamental misunderstanding, the question is senseless.
The misunderstanding was yours. The nastiness too.
I have no misunderstanding. The manufacturers don\'t specify the \"drive power\" of the batteries in their EV. Why would the consumer need to know that? They do specify battery capacity of their EV because it gives the consumer an idea of expected range.

The OP is clearly confusing battery capacity with \"drive power.\"

That big Ford truck only puts out 2.4kW with its V2H bidirectional charger, with plans to maybe introduce one with 9.6kW sometime in the future. And even the small one adds thousands to the price of the vehicle. They\'re not going to waste a bunch of money making something people won\'t buy in the volume necessary to make a profit.

The question made sense. Why a 10 KW inverter? The answer is probably,
it\'s enough for a house backup and a bigger inverter would cost more.
That Ford thing wouldn\'t even turn over a 2 ton a/c. Looks like they just gave up powering the big stuff. Looks like they\'re going for 30 hours continuous at rated backup peak and the homeowner can take if from there, settling for less or more, it\'s up to them how they load or unload it.

Battery cooling could be involved too, for a parked car.
Do batteries get all that hot in discharge?
Absolutely, when you push the performance of the car. I saw a video of a German guy on the autobahn, driving as fast as he could. This involved not only acceleration, but deceleration, which ultimately overheated the car. I can\'t say for sure if it was the motor or battery, but the continued high current, in and out of the battery will absolutely raise the battery temperature and the cooling is important to the longevity of the battery.
Oh yeah- that fictitious autobahn with its 100 km/h speed limit that most Americans equate to 100 mph when it\'s actually 60.
The operative word is current into the battery- that will do it. I don\'t know the first thing about their motor, but I can see there might be surge currents in the windings (more I^2R losses) until the rotor spins up with enough counter emf in the rapid speed changing scenario. That will heat things up. Maybe something similar happens in V2H when the house abruptly turns on a heavy load. But that\'s a one shot transient and doesn\'t repeat with any kind frequency, hard to believe it will overheat the battery.

Hmmm... There are always I2R losses in the motor. You don\'t need to worry with the details of \"spinning up\". The more power the motor is handling, the higher the current and the more I2R losses. Notice the \'2\' in I2R? The waste power goes up with the square of the current. So higher road speeds, and especially accelerating and decelerating will heat up the motor and battery quickly.

--

Rick C.

+++ Get 1,000 miles of free Supercharging
+++ Tesla referral code - https://ts.la/richard11209

 

[Martin Brown]

On 17/11/2022 19:18, Ricky wrote:

On Thursday, November 17, 2022 at 2:12:13 PM UTC-5, Carlos E.R.
wrote:
On 2022-11-17 17:12, Ricky wrote:
On Thursday, November 17, 2022 at 8:39:52 AM UTC-5, Martin Brown
wrote:
...
And why do people say it costs thousands of dollars to
fit something to do this? Surely a 10kW invertor doesn\'t
cost much, just something to make 400VDC into 240VAC. I\'d
say more like 500 dollars.

Yep, a couple of quid for the battery, a few more quid for
the casing, employ some untrained monkey on minimum wage to
fit it to the grid with bell wire, a small inverter and a
suicide lead to plug it back into a convenient 3 pin socket
when the backup is needed.

What battery? The battery is already in the car. All you need
is a convertor from 400VDC to 240VAC, and if you want it
automated, a big contactor to switch to the car and back.
A Tesla powerwall battery ~14kWh intended for home use has an
inverter that can only output about 7kW peak and 5kW
continuous.

https://electrek.co/2021/04/22/tesla-increasing-powerwall-power-capacity/

Yeah, they are a bit limited too. Try using one as your primary backup.
When it kicks in, your electric use is suddenly limited.

Mine would be more than doubled. A typical home here has 3.6 or 4.8
KW max.

3.6 kW is only 15A at 240V. I\'m told that in the UK, when an
important football game is on, there\'s a power surge from the 9 amp
kettles going on during commercials. I guess where you live, they

Half time at a major sporting event is a major coherent spike in grid
power usage and they need to be ready for it.

They are not 9A kettles either. The typical UK kettle now is 2.4kW/10A
although many older kettles like mine are 3kW/13A. The maximum load that
a nominal 13A socket can take continuously has been recently downgraded.

Too many cheap and nasty Chinese ones melted with continuous 13A loads.
Notably with increased use of 3kW fan heaters to heat a single room
(causing other problems as well in this energy crisis).

https://metro.co.uk/2022/11/15/cost-of-living-crisis-fire-safety-warning-over-electric-heaters-17753200/

Becoming a problem right now as rising energy prices mean people turn
off CH and heat just one room with an old electric fan heater to save
money. Older ones are invariably 3kW and the modern \"13A\" sockets are
made down to a price and not really up to it. Once they start to fail by
overheating the damage quickly becomes exponentially bad.

Warming up a room from cold with a solid 3kW 13A continuous load
stresses some sockets beyond the point where they become serious hot
after an hour or so.

have to turn off the TV to run the kettle. Or maybe they unplug the
refrigerator?

When we lived in Japan it was the same. A kettle was a thermally
insulated vessel that kept water near ready to use temperature and
consumed energy 24/7 to keep it that way. It took forever to get hot
boiling water after refilling it with just 500W peak consumption. You
gave it a boost to go from 90+C to boiling prior to use.

Having aircon, immersion heater and washing machine on at the same time
would take out the MCB for overload. We found that out the hard way.

ISTR In Europe Spain, Greece and Italy have rather feeble domestic supply.

UK mains is traditionally something like 40A (1950\'s build) increasing
by about 20A for every few decades since. My house fuse is 60A I tried
to sweet talk the engineer into putting in an electric car ready 100A
fuse when he replaced the meter recently but they aren\'t allowed to.

No technical reason why not - electric company charges for the upgrade
to 100A whereas meter replacement is free.

> Where exactly is \"here\"?

Spain or Italy at a guess. Greece is (was?) similar.

--
Regards,
Martin Brown

 

[Martin Brown]

On 17/11/2022 19:12, Ricky wrote:

On Thursday, November 17, 2022 at 2:04:22 PM UTC-5, Fred Bloggs wrote:
On Thursday, November 17, 2022 at 11:59:31 AM UTC-5, Joe Gwinn wrote:
On Thu, 17 Nov 2022 13:39:36 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 17/11/2022 13:19, Commander Kinsey wrote:
On Thu, 17 Nov 2022 09:54:42 -0000, alan_m <ju...@admac.myzen.co.uk> wrote:

On 17/11/2022 09:27, Commander Kinsey wrote:
If an EV has an output power of say 80kW to drive the motors when
driving, why is the backup power (to power your house in a power outage)
only about 10kW? It\'s the same battery!

The average usage of electricity per day for a UK household is less than
10kWh so a 10kWh backup battery will supply power for a day or more in
the event of a power cut.

No, 10kW. I did not type an h.

10kW is a fairly reasonable figure for powering a home. Over engineering
it to do 20kW or 40kW continuous would not be good value for money.
In the UK, perhaps. In the US, lots of homes have gone to 100-amp 220
Vac split phase, or 22 KW. Some have twice that.

My house has 100 amp service. But we have a gas stove and water
heater, and oil heat. No electric heat. My shop runs off 220 Vac,
but the big machines are only used intermittently, but will need a lot
of power when doing something heavy.

Most appliances (including air conditioners) are 120 Vac and 15 or 20
amps. Things like clothes dryers are 220 Vac. Many people have
electric water heaters. also 220 Vac.
This table is pretty close, except for some things like their ridiculously low estimate of an electric range. Go down the list and add them up. Some things need to be permanently shut off/ not used in backup mode.

https://unboundsolar.com/solar-information/power-table

Some of their values seem rather high to me but otherwise mostly OK.

> They don\'t list an electric range.

Typically 6-8kW if all the halogen rings are on at once from cold.

About 2kW per ring when they are actively heating. Once each one is hot
they pulse on and off. I expect induction ones to be a bit less but near
continuous whereas halogen hobs are very bang bang regulation.

Obviously it has to be wired to cope with the worst case scenario. Ovens
by comparison have become so well insulated now that 1kW suffices (and
once it is up to temperature the average is even lower).

The kitchen supply for the electric cooker got its own dedicated thicker
cable in most installations. It is a bit overkill now that ovens have
become so much more thermally efficient.

--
Regards,
Martin Brown

 

[Carlos E.R.]

On 2022-11-18 02:23, Ricky wrote:

On Thursday, November 17, 2022 at 8:00:13 PM UTC-5, Carlos E.R. wrote:
On 2022-11-18 01:20, Ricky wrote:
On Thursday, November 17, 2022 at 4:36:12 PM UTC-5, Carlos E.R. wrote:
On 2022-11-17 21:34, Ricky wrote:
On Thursday, November 17, 2022 at 2:44:13 PM UTC-5, Carlos E.R. wrote:
On 2022-11-17 20:18, Ricky wrote:
On Thursday, November 17, 2022 at 2:12:13 PM UTC-5, Carlos E.R. wrote:
On 2022-11-17 17:12, Ricky wrote:
On Thursday, November 17, 2022 at 8:39:52 AM UTC-5, Martin Brown wrote:
...
And why do people say it costs thousands of dollars to fit something to
do this? Surely a 10kW invertor doesn\'t cost much, just something to
make 400VDC into 240VAC. I\'d say more like 500 dollars.

Yep, a couple of quid for the battery, a few more quid for the casing,
employ some untrained monkey on minimum wage to fit it to the grid with
bell wire, a small inverter and a suicide lead to plug it back into a
convenient 3 pin socket when the backup is needed.

What battery? The battery is already in the car. All you need is a
convertor from 400VDC to 240VAC, and if you want it automated, a big
contactor to switch to the car and back.
A Tesla powerwall battery ~14kWh intended for home use has an inverter
that can only output about 7kW peak and 5kW continuous.

https://electrek.co/2021/04/22/tesla-increasing-powerwall-power-capacity/

Yeah, they are a bit limited too. Try using one as your primary backup. When it kicks in, your electric use is suddenly limited.
Mine would be more than doubled.
A typical home here has 3.6 or 4.8 KW max.

3.6 kW is only 15A at 240V. I\'m told that in the UK, when an important football game is on, there\'s a power surge from the 9 amp kettles going on during commercials.
I heard :-D
I guess where you live, they have to turn off the TV to run the kettle. Or maybe they unplug the refrigerator?
Nope. Why? A coffee maker is about 1 KW tops. The TV a hundred or two,
depending on size. Mine is maybe fifty.

Where exactly is \"here\"?
My address says \"Spain\".

\"Only\" 1 kW? That\'s more than a quarter of the entire feed! I\'ve been lead to believe a kettle is 9 amps on 240V circuits so it heats quicker (getting them back to the game I suppose).
https://www.nespresso.com/shared_res/manuals/inissia/inissia_D_delonghi.pdf

Page 8.

220-240 v, 50-60 Hz, 1150-1260 W

It gets ready to make the first coffee in twenty seconds, IIRC.

That\'s not a kettle. I guess that something you are not familiar with. Still, when you only have 6 kW available, you have to count everything you plug in at one time.
I am familiar with kettles, but people here prefer coffee. Tea they
usually would make in the microwave

I do have a kettle, though. Some 800 W, I think it is.
In the US devices mostly max out at 12 amps, so 1.44 kW. I guess in Spain they are not in such a hurry. No air conditioning either?
Yes, we have AC when we want it. Me, only one room, less than 1 KW.
Other people, may do the entire flat. And pay more.

Yes, that\'s how most people live in Puerto Rico. They also don\'t put their used used toilet paper in the toilet, I discovered. You are free to live how you want. I expect not everyone in Spain lives alone, in their bedroom.
Nor everybody lives alone in a house fit for 6 people.
That and heat pump heating are the top of the list for power draw. Even without those, my small family house built in the early \'60s had 100 amp service. I can\'t imagine all the juggling I\'d have to do to keep under 15 amps at all times. Heck, my hot water heater draws something like 17-18 amps, which is churning away at the moment because I just got out of a hot shower.
My 50l hot water tank is 1KW (actually, I put a diode in series to lower
it by half). A 300 litres unit, for eight people, takes 3 KW. If you
have such a big house, normally you would contract for more electricity.

Yes, that is my point. Your 3.6 kW house is a bit of an outlier.
On the contrary, 3.6 is typical, on flats (the majority of the people
here live in flats). Mine is just 2.4.

I\'m sorry, 2.4 kW is just 10 amps at 240V. Now you really are in Green Acres territory. I never realized Spain was this way.

You are getting it wrong. It is not Spain, it is this house.

https://i.etsystatic.com/15342879/r/il/aa8ee7/3950142638/il_1588xN.3950142638_gsdx.jpg

I have no doubt that 99% of the population has much larger feeds than you do.


https://www.leroymerlin.es/productos/marcas/equation/termos-electricos-equation/termo-electrico-equation-eq2-300l-82005360.html

Heating here is normally done with gas. In fact, I don\'t use the hot
water tank (electric), but a butane flash heater. Much cheaper.


We simply do not connect all appliances simultaneously.

And that has been my point. You *can\'t* use your appliances simultaneously. You have to be careful about what you plug in.
Certainly. Cheaper, more environmentally conscious.

LOL. It has nothing to do with electrical use or being environmentally conscious. A kWh is a kWh, whether you run the refrigerator all day, or if you have to unplug it to make toast.

Certainly.

It is still cheaper here to have a 20 A fuse to the house than a 40 A
fuse, even if you use the same amount of kwh per day.

https://www.youtube.com/watch?v=WGPMadwqPKQ


Here, we pay a monthly fee for the size of the electricity \"pipe\", and
it is expensive. So people optimize the maximum current they contract
from the electricity supplier. If you want the AC at the same time you
put the oven and the dishwasher, you have to pay for the pipe plus the
actual electricity you use.

It is as simple as that.

Yes, we do the same, but it doesn\'t dominate the bill. So we size the feed to suit our needs, which is typically 200A or more in larger houses. I suppose there are 100A feeds in very small houses. Stoves mostly run at peak time in the US, a time when you want the air conditioning. Being prevented from running both is something I would hate to be faced with.

But it would be silly for a utility to price the feed size to discourage users from using as much electricity. Normally they want to maximize their profits, which means, encouraging more appliances. I think I mentioned elsewhere in this thread that in the 70s, the US electric companies were actively promoting electrical appliances to the point people would install electrical radiant heat. Then the price of electricity started going up and it got real expensive.
Well, it suits better to them to maximize profits without having to
install the generation capacity, nor using that fuel. A capacity that a
lot of the time would be idle, just to contemplate everybody making tea
the same minute.

You clearly don\'t understand the grid. Your bottleneck controls how much power you can use at the same time, not how much energy you can use. The grid will still need to provide the same energy to make your toast and power the refrigerator, even if you have to unplug one to run the other. You only reduce the energy supplied by the grid if you give up on the idea of making toast because it\'s too big a PITA. When you average over everyone unplugging their refrigerators to make toast, the same load is on the grid.

It is you who doesn\'t understand.

Having the grid capacity so that everyone is guaranteed to be able to
draw 100 A at the same time (that is the legal meaning here, as
everybody would have a contract to do just that) means the grid needs
that capacity, which is expensive - even if they sit at 1 A the rest of
the day.

What is stupid is refusing to understand that the world doesn\'t follow
the same customs and ways as your country. There are different ways out
there, and getting angry when someone simply tells you of the differences.

I\'ve had enough of this silly conversation. You can have the last comment.

--
Cheers, Carlos.

 

[Martin Brown]

On 17/11/2022 19:00, Ricky wrote:

On Thursday, November 17, 2022 at 11:59:31 AM UTC-5, Joe Gwinn
wrote:
On Thu, 17 Nov 2022 13:39:36 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

10kW is a fairly reasonable figure for powering a home. Over
engineering it to do 20kW or 40kW continuous would not be good
value for money.
In the UK, perhaps. In the US, lots of homes have gone to 100-amp
220 Vac split phase, or 22 KW. Some have twice that.

No home in the US have gone to 100-amp, 220VAC split phase. The
nominal voltage in the US is 240V. I expect very few homes in the US
have been built with 100 amp service in the last 50 years. In the
70s, there was a big push to use more electric appliances, including
electric radiant heat! You aren\'t getting that with 100 amp
service.

Since US domestic power is nominal 110v I\'d have thought that 100A per
live feed was about right (bordering on the low side). OTOH high power
devices like aircon are run phase to phase on 220v.

My feed is 60A @ 230v ~ 14kW modern build here would be 100A ~ 23kW

Base load 24/7 is 70W typical daytime load ~300W peak maybe 6kW.

My house has 100 amp service. But we have a gas stove and water
heater, and oil heat. No electric heat. My shop runs off 220 Vac,
but the big machines are only used intermittently, but will need a
lot of power when doing something heavy.

Do you have a 240V to 220V transformer? If not, you have excessive
voltage drop coming to your house and should ask the power company to
fix that.

UK says it has 240v but in reality all of Europe uses a ~230v nominal
voltage with an asymmetric tolerance band see for example:

www.spenergynetworks.co.uk/pages/voltage_changes.aspx#:~:text=declared,216.2%20volts%20to%20253.0%20volts.

Most appliances (including air conditioners) are 120 Vac and 15 or
20 amps. Things like clothes dryers are 220 Vac. Many people have
electric water heaters. also 220 Vac.

If you have 120V on the low voltage outlets, how do you get 220V on
the high voltage circuits? Is your line not balanced with one at
120V and the other at 100V?

It is likely that as in the UK confusion reigns about actual mains
voltage - so few consumers ever measure it and think they have 240v. It
could in reality be as low as 216 or high as 253 and still (just) in spec.

In most of Europe it is likely to be 230v nominal 115v-0-115v balanced
or it could be full three phase supply to industrial premises.

--
Regards,
Martin Brown

 

[Ricky]

On Friday, November 18, 2022 at 5:36:14 AM UTC-5, Carlos E.R. wrote:

On 2022-11-18 02:23, Ricky wrote:
On Thursday, November 17, 2022 at 8:00:13 PM UTC-5, Carlos E.R. wrote:
On 2022-11-18 01:20, Ricky wrote:
On Thursday, November 17, 2022 at 4:36:12 PM UTC-5, Carlos E.R. wrote:
On 2022-11-17 21:34, Ricky wrote:
On Thursday, November 17, 2022 at 2:44:13 PM UTC-5, Carlos E.R. wrote:
On 2022-11-17 20:18, Ricky wrote:
On Thursday, November 17, 2022 at 2:12:13 PM UTC-5, Carlos E.R. wrote:
On 2022-11-17 17:12, Ricky wrote:
On Thursday, November 17, 2022 at 8:39:52 AM UTC-5, Martin Brown wrote:
...
And why do people say it costs thousands of dollars to fit something to
do this? Surely a 10kW invertor doesn\'t cost much, just something to
make 400VDC into 240VAC. I\'d say more like 500 dollars.

Yep, a couple of quid for the battery, a few more quid for the casing,
employ some untrained monkey on minimum wage to fit it to the grid with
bell wire, a small inverter and a suicide lead to plug it back into a
convenient 3 pin socket when the backup is needed.

What battery? The battery is already in the car. All you need is a
convertor from 400VDC to 240VAC, and if you want it automated, a big
contactor to switch to the car and back.
A Tesla powerwall battery ~14kWh intended for home use has an inverter
that can only output about 7kW peak and 5kW continuous.

https://electrek.co/2021/04/22/tesla-increasing-powerwall-power-capacity/

Yeah, they are a bit limited too. Try using one as your primary backup. When it kicks in, your electric use is suddenly limited.
Mine would be more than doubled.
A typical home here has 3.6 or 4.8 KW max.

3.6 kW is only 15A at 240V. I\'m told that in the UK, when an important football game is on, there\'s a power surge from the 9 amp kettles going on during commercials.
I heard :-D
I guess where you live, they have to turn off the TV to run the kettle. Or maybe they unplug the refrigerator?
Nope. Why? A coffee maker is about 1 KW tops. The TV a hundred or two,
depending on size. Mine is maybe fifty.

Where exactly is \"here\"?
My address says \"Spain\".

\"Only\" 1 kW? That\'s more than a quarter of the entire feed! I\'ve been lead to believe a kettle is 9 amps on 240V circuits so it heats quicker (getting them back to the game I suppose).
https://www.nespresso.com/shared_res/manuals/inissia/inissia_D_delonghi.pdf

Page 8.

220-240 v, 50-60 Hz, 1150-1260 W

It gets ready to make the first coffee in twenty seconds, IIRC.

That\'s not a kettle. I guess that something you are not familiar with.. Still, when you only have 6 kW available, you have to count everything you plug in at one time.
I am familiar with kettles, but people here prefer coffee. Tea they
usually would make in the microwave

I do have a kettle, though. Some 800 W, I think it is.
In the US devices mostly max out at 12 amps, so 1.44 kW. I guess in Spain they are not in such a hurry. No air conditioning either?
Yes, we have AC when we want it. Me, only one room, less than 1 KW.
Other people, may do the entire flat. And pay more.

Yes, that\'s how most people live in Puerto Rico. They also don\'t put their used used toilet paper in the toilet, I discovered. You are free to live how you want. I expect not everyone in Spain lives alone, in their bedroom.
Nor everybody lives alone in a house fit for 6 people.
That and heat pump heating are the top of the list for power draw. Even without those, my small family house built in the early \'60s had 100 amp service. I can\'t imagine all the juggling I\'d have to do to keep under 15 amps at all times. Heck, my hot water heater draws something like 17-18 amps, which is churning away at the moment because I just got out of a hot shower.
My 50l hot water tank is 1KW (actually, I put a diode in series to lower
it by half). A 300 litres unit, for eight people, takes 3 KW. If you
have such a big house, normally you would contract for more electricity.

Yes, that is my point. Your 3.6 kW house is a bit of an outlier.
On the contrary, 3.6 is typical, on flats (the majority of the people
here live in flats). Mine is just 2.4.

I\'m sorry, 2.4 kW is just 10 amps at 240V. Now you really are in Green Acres territory. I never realized Spain was this way.
You are getting it wrong. It is not Spain, it is this house.

You seem to be inconsistent. I say you are an outlier, and you say, no, this is common. Now you say it\'s just this house.

I\'ve reached the point of not caring. You don\'t have a point to make. You just want to talk in circles.

https://i.etsystatic.com/15342879/r/il/aa8ee7/3950142638/il_1588xN.3950142638_gsdx.jpg

I have no doubt that 99% of the population has much larger feeds than you do.


https://www.leroymerlin.es/productos/marcas/equation/termos-electricos-equation/termo-electrico-equation-eq2-300l-82005360.html

Heating here is normally done with gas. In fact, I don\'t use the hot
water tank (electric), but a butane flash heater. Much cheaper.


We simply do not connect all appliances simultaneously.

And that has been my point. You *can\'t* use your appliances simultaneously. You have to be careful about what you plug in.
Certainly. Cheaper, more environmentally conscious.

LOL. It has nothing to do with electrical use or being environmentally conscious. A kWh is a kWh, whether you run the refrigerator all day, or if you have to unplug it to make toast.
Certainly.

It is still cheaper here to have a 20 A fuse to the house than a 40 A
fuse, even if you use the same amount of kwh per day.

But nothing to do with the environment. It\'s only cheaper because of your local utility emphasizing a high cost for a larger feed, which is not very typical in the grand scheme of things. Given your wandering thoughts, I would not be surprised to find out the cost difference is very small and you are just exaggerating it.

https://www.youtube.com/watch?v=WGPMadwqPKQ


Here, we pay a monthly fee for the size of the electricity \"pipe\", and
it is expensive. So people optimize the maximum current they contract
from the electricity supplier. If you want the AC at the same time you
put the oven and the dishwasher, you have to pay for the pipe plus the
actual electricity you use.

It is as simple as that.

Yes, we do the same, but it doesn\'t dominate the bill. So we size the feed to suit our needs, which is typically 200A or more in larger houses. I suppose there are 100A feeds in very small houses. Stoves mostly run at peak time in the US, a time when you want the air conditioning. Being prevented from running both is something I would hate to be faced with.

But it would be silly for a utility to price the feed size to discourage users from using as much electricity. Normally they want to maximize their profits, which means, encouraging more appliances. I think I mentioned elsewhere in this thread that in the 70s, the US electric companies were actively promoting electrical appliances to the point people would install electrical radiant heat. Then the price of electricity started going up and it got real expensive.
Well, it suits better to them to maximize profits without having to
install the generation capacity, nor using that fuel. A capacity that a
lot of the time would be idle, just to contemplate everybody making tea
the same minute.

You clearly don\'t understand the grid. Your bottleneck controls how much power you can use at the same time, not how much energy you can use. The grid will still need to provide the same energy to make your toast and power the refrigerator, even if you have to unplug one to run the other. You only reduce the energy supplied by the grid if you give up on the idea of making toast because it\'s too big a PITA. When you average over everyone unplugging their refrigerators to make toast, the same load is on the grid.
It is you who doesn\'t understand.

Having the grid capacity so that everyone is guaranteed to be able to
draw 100 A at the same time (that is the legal meaning here, as
everybody would have a contract to do just that) means the grid needs
that capacity, which is expensive - even if they sit at 1 A the rest of
the day.

No one with any intelligence designs a grid like that. Here, we have a transformer shared by two to four houses. They don\'t even size that to allow all the houses sharing the transformer to run full tilt continuously. They understand the statistical nature of energy usage... other than a commercials in a football game.

What is stupid is refusing to understand that the world doesn\'t follow
the same customs and ways as your country. There are different ways out
there, and getting angry when someone simply tells you of the differences..

No one is angry. I\'m just pointing out that much of what you write is inconsistent and clearly erroneous. If you don\'t understand your grid, I don\'t expect you to be able to explain it.

--

Rick C.

---- Get 1,000 miles of free Supercharging
---- Tesla referral code - https://ts.la/richard11209

 

[Ricky]

On Friday, November 18, 2022 at 5:37:56 AM UTC-5, Martin Brown wrote:

On 17/11/2022 19:00, Ricky wrote:
On Thursday, November 17, 2022 at 11:59:31 AM UTC-5, Joe Gwinn
wrote:
On Thu, 17 Nov 2022 13:39:36 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

10kW is a fairly reasonable figure for powering a home. Over
engineering it to do 20kW or 40kW continuous would not be good
value for money.
In the UK, perhaps. In the US, lots of homes have gone to 100-amp
220 Vac split phase, or 22 KW. Some have twice that.

No home in the US have gone to 100-amp, 220VAC split phase. The
nominal voltage in the US is 240V. I expect very few homes in the US
have been built with 100 amp service in the last 50 years. In the
70s, there was a big push to use more electric appliances, including
electric radiant heat! You aren\'t getting that with 100 amp
service.

Since US domestic power is nominal 110v I\'d have thought that 100A per
live feed was about right (bordering on the low side). OTOH high power
devices like aircon are run phase to phase on 220v.

You don\'t even have the voltage right, so why would you understand the power?

My feed is 60A @ 230v ~ 14kW modern build here would be 100A ~ 23kW

Base load 24/7 is 70W typical daytime load ~300W peak maybe 6kW.
My house has 100 amp service. But we have a gas stove and water
heater, and oil heat. No electric heat. My shop runs off 220 Vac,
but the big machines are only used intermittently, but will need a
lot of power when doing something heavy.

Do you have a 240V to 220V transformer? If not, you have excessive
voltage drop coming to your house and should ask the power company to
fix that.
UK says it has 240v but in reality all of Europe uses a ~230v nominal
voltage with an asymmetric tolerance band see for example:

www.spenergynetworks.co.uk/pages/voltage_changes.aspx#:~:text=declared,216.2%20volts%20to%20253.0%20volts.

Most appliances (including air conditioners) are 120 Vac and 15 or
20 amps. Things like clothes dryers are 220 Vac. Many people have
electric water heaters. also 220 Vac.

If you have 120V on the low voltage outlets, how do you get 220V on
the high voltage circuits? Is your line not balanced with one at
120V and the other at 100V?
It is likely that as in the UK confusion reigns about actual mains
voltage - so few consumers ever measure it and think they have 240v. It
could in reality be as low as 216 or high as 253 and still (just) in spec.

In most of Europe it is likely to be 230v nominal 115v-0-115v balanced
or it could be full three phase supply to industrial premises.

I seldom have any idea why you say the things you say. Doesn\'t matter much.

--

Rick C.

---+ Get 1,000 miles of free Supercharging
---+ Tesla referral code - https://ts.la/richard11209

 

[Martin Brown]

On 18/11/2022 01:36, Ed Lee wrote:

On Thursday, November 17, 2022 at 5:30:44 PM UTC-8, Ricky wrote:
On Thursday, November 17, 2022 at 8:18:50 PM UTC-5, Ed Lee wrote:
On Thursday, November 17, 2022 at 5:00:38 PM UTC-8, Fred Bloggs wrote:
On Thursday, November 17, 2022 at 3:58:36 PM UTC-5, John Larkin wrote:
On Thu, 17 Nov 2022 10:32:33 -0800 (PST), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

On Thursday, November 17, 2022 at 10:30:31 AM UTC-5, John Larkin wrote:
On Thu, 17 Nov 2022 05:03:57 -0800 (PST), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

On Thursday, November 17, 2022 at 4:27:46 AM UTC-5, Commander Kinsey wrote:
If an EV has an output power of say 80kW to drive the motors when driving, why is the backup power (to power your house in a power outage) only about 10kW? It\'s the same battery!

And why do people say it costs thousands of dollars to fit something to do this? Surely a 10kW invertor doesn\'t cost much, just something to make 400VDC into 240VAC. I\'d say more like 500 dollars.

You need to learn the difference between energy and power. The 80kW is really 80kWh(hours), a measure of energy stored in the battery. The 10kW is a measure of power which is the rate of energy extraction from the battery, usually specified in kW, kilo-watts, thousands of Watts. There is no logical connection between the two ratings. The engineering requirements of the battery EV application determines that.

He clearly said that the battery can deliver 80 KW of power. No 80 KWH
car is going to be limited to 10 KW into the motors. Ecars are all
about acceleration.

That 80kW is quoted quite often as the battery capacity when they mean 80kWh of course. Without that as his fundamental misunderstanding, the question is senseless.
The misunderstanding was yours. The nastiness too.
I have no misunderstanding. The manufacturers don\'t specify the \"drive power\" of the batteries in their EV. Why would the consumer need to know that? They do specify battery capacity of their EV because it gives the consumer an idea of expected range.
3 miles per kwhr is a good rule of thumb. So, if you need to drive 60MPH, then you need around 20kW drive power. I don\'t know why people need 150kW, unless they are driving 450MPH.
3 miles per kWh is a good number for an electron guzzler like my X. The less bloated cars like the 3 and Y get more like 4 miles per kWh and I\'d lump the Nissan Leaf into 4 miles per kWh group from everything I\'ve heard.

So, 150kW drive power can get up to 600MPH.

Air resistance causes drag forces which robs power as the cube of
velocity becomes distinctly non-negligible from 60mph upwards so you are
being rather over optimistic there.

https://en.wikipedia.org/wiki/Drag_(physics)

The 80kW or 150kW is so they can claim 100Hp or 180Hp and have 0-60
times that are in the supercar league. It tends to wear the tyres out if
you spend too much time going from 0 to 60mph in the shortest time.


--
Regards,
Martin Brown

 

[Ed Lee]

On Friday, November 18, 2022 at 3:17:18 AM UTC-8, Martin Brown wrote:

On 18/11/2022 01:36, Ed Lee wrote:
On Thursday, November 17, 2022 at 5:30:44 PM UTC-8, Ricky wrote:
On Thursday, November 17, 2022 at 8:18:50 PM UTC-5, Ed Lee wrote:
On Thursday, November 17, 2022 at 5:00:38 PM UTC-8, Fred Bloggs wrote:
On Thursday, November 17, 2022 at 3:58:36 PM UTC-5, John Larkin wrote:
On Thu, 17 Nov 2022 10:32:33 -0800 (PST), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

On Thursday, November 17, 2022 at 10:30:31 AM UTC-5, John Larkin wrote:
On Thu, 17 Nov 2022 05:03:57 -0800 (PST), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

On Thursday, November 17, 2022 at 4:27:46 AM UTC-5, Commander Kinsey wrote:
If an EV has an output power of say 80kW to drive the motors when driving, why is the backup power (to power your house in a power outage) only about 10kW? It\'s the same battery!

And why do people say it costs thousands of dollars to fit something to do this? Surely a 10kW invertor doesn\'t cost much, just something to make 400VDC into 240VAC. I\'d say more like 500 dollars.

You need to learn the difference between energy and power. The 80kW is really 80kWh(hours), a measure of energy stored in the battery. The 10kW is a measure of power which is the rate of energy extraction from the battery, usually specified in kW, kilo-watts, thousands of Watts. There is no logical connection between the two ratings. The engineering requirements of the battery EV application determines that.

He clearly said that the battery can deliver 80 KW of power. No 80 KWH
car is going to be limited to 10 KW into the motors. Ecars are all
about acceleration.

That 80kW is quoted quite often as the battery capacity when they mean 80kWh of course. Without that as his fundamental misunderstanding, the question is senseless.
The misunderstanding was yours. The nastiness too.
I have no misunderstanding. The manufacturers don\'t specify the \"drive power\" of the batteries in their EV. Why would the consumer need to know that? They do specify battery capacity of their EV because it gives the consumer an idea of expected range.
3 miles per kwhr is a good rule of thumb. So, if you need to drive 60MPH, then you need around 20kW drive power. I don\'t know why people need 150kW, unless they are driving 450MPH.
3 miles per kWh is a good number for an electron guzzler like my X. The less bloated cars like the 3 and Y get more like 4 miles per kWh and I\'d lump the Nissan Leaf into 4 miles per kWh group from everything I\'ve heard.

So, 150kW drive power can get up to 600MPH.
Air resistance causes drag forces which robs power as the cube of
velocity becomes distinctly non-negligible from 60mph upwards so you are
being rather over optimistic there.

https://en.wikipedia.org/wiki/Drag_(physics)

The 80kW or 150kW is so they can claim 100Hp or 180Hp and have 0-60
times that are in the supercar league. It tends to wear the tyres out if
you spend too much time going from 0 to 60mph in the shortest time.

That\'s my point exactly. Anything over 50kW drive (motor) is just theoretical (marketing).

 

[Martin Brown]

On 18/11/2022 11:08, Ricky wrote:

On Friday, November 18, 2022 at 5:36:14 AM UTC-5, Carlos E.R. wrote:
On 2022-11-18 02:23, Ricky wrote:
On Thursday, November 17, 2022 at 8:00:13 PM UTC-5, Carlos E.R.
wrote:
On 2022-11-18 01:20, Ricky wrote:
On Thursday, November 17, 2022 at 4:36:12 PM UTC-5, Carlos
E.R. wrote:
On 2022-11-17 21:34, Ricky wrote:
That and heat pump heating are the top of the list for
power draw. Even without those, my small family house
built in the early \'60s had 100 amp service. I can\'t
imagine all the juggling I\'d have to do to keep under 15
amps at all times. Heck, my hot water heater draws
something like 17-18 amps, which is churning away at the
moment because I just got out of a hot shower.

My 50l hot water tank is 1KW (actually, I put a diode in
series to lower it by half). A 300 litres unit, for eight
people, takes 3 KW. If you have such a big house, normally
you would contract for more electricity.

Yes, that is my point. Your 3.6 kW house is a bit of an
outlier.
On the contrary, 3.6 is typical, on flats (the majority of the
people here live in flats). Mine is just 2.4.

I\'m sorry, 2.4 kW is just 10 amps at 240V. Now you really are in
Green Acres territory. I never realized Spain was this way.

You are getting it wrong. It is not Spain, it is this house.

You seem to be inconsistent. I say you are an outlier, and you say,
no, this is common. Now you say it\'s just this house.

I\'ve reached the point of not caring. You don\'t have a point to
make. You just want to talk in circles.

I have no doubt that 99% of the population has much larger feeds than
you do.

I wouldn\'t be so sure of that. My recollection is that domestic power in
several European countries is very much lower than in the UK with a 20A
main fuse being common in rural areas. Same when I lived in Japan too.

Having the grid capacity so that everyone is guaranteed to be able
to draw 100 A at the same time (that is the legal meaning here, as
everybody would have a contract to do just that) means the grid
needs that capacity, which is expensive - even if they sit at 1 A
the rest of the day.

No one with any intelligence designs a grid like that. Here, we have
a transformer shared by two to four houses. They don\'t even size
that to allow all the houses sharing the transformer to run full tilt
continuously. They understand the statistical nature of energy
usage... other than a commercials in a football game.

They rely on diversity of use. An assumption that is broken around
evening meal times and especially at half time of major sporting events.
UK National Grid is offering people with smart meters an incentive not
to run heavy loads at peak times during this winter.

Unclear if it will work my electricity supplier isn\'t taking part

Fortunately peak load per household seldom exceeds 10A at the same time
so the distribution network is never under threat.

What is stupid is refusing to understand that the world doesn\'t
follow the same customs and ways as your country. There are
different ways out there, and getting angry when someone simply
tells you of the differences.

No one is angry. I\'m just pointing out that much of what you write
is inconsistent and clearly erroneous. If you don\'t understand your
grid, I don\'t expect you to be able to explain it.

He is describing the sort of mains power that is quite common in Spain,
Italy and a few other southern European countries and Japan too. Belgium
by comparison had about the same fusing as in the UK - in fact their
phone connectors also looked like they were rated for about 10A!

https://nl.forum.proximus.be/archieven-2010-2017-44/internet-valt-weg-bij-gebruik-vaste-telefoon-41593

For scale the round pins are ~3mm diameter the whole thing 2\" square.
They were mostly a sort of weird oval shape when I lived there.


--
Regards,
Martin Brown

 

[Carlos E.R.]

On 2022-11-18 12:46, Martin Brown wrote:

On 18/11/2022 11:08, Ricky wrote:
On Friday, November 18, 2022 at 5:36:14 AM UTC-5, Carlos E.R. wrote:
On 2022-11-18 02:23, Ricky wrote:
On Thursday, November 17, 2022 at 8:00:13 PM UTC-5, Carlos E.R.
wrote:
On 2022-11-18 01:20, Ricky wrote:
On Thursday, November 17, 2022 at 4:36:12 PM UTC-5, Carlos
E.R. wrote:
On 2022-11-17 21:34, Ricky wrote:
That and heat pump heating are the top of the list for
power draw. Even without those, my small family house
built in the early \'60s had 100 amp service. I can\'t
imagine all the juggling I\'d have to do to keep under 15
amps at all times. Heck, my hot water heater draws
something like 17-18 amps, which is churning away at the
moment because I just got out of a hot shower.

My 50l hot water tank is 1KW (actually, I put a diode in
series to lower it by half). A 300 litres unit, for eight
people, takes 3 KW. If you have such a big house, normally
you would contract for more electricity.

Yes, that is my point. Your 3.6 kW house is a bit of an
outlier.
On the contrary, 3.6 is typical, on flats (the majority of the
people here live in flats). Mine is just 2.4.

I\'m sorry, 2.4 kW is just 10 amps at 240V. Now you really are in
Green Acres territory. I never realized Spain was this way.

You are getting it wrong. It is not Spain, it is this house.

You seem to be inconsistent.  I say you are an outlier, and you say,
no, this is common.  Now you say it\'s just this house.

Or you (Ricky) have some reading problems.

I said the typical home here has a 3.6 KW contract and limit.

I also said that mine is just 2.4 KW contract and limit, and is not a
small house. It is significantly bigger than the average. You might ask
(politely) why I have such a small pipe, or not. But do not assume
things that you do not know.

I\'ve reached the point of not caring.   You don\'t have a point to
make.  You just want to talk in circles.

I have no doubt that 99% of the population has much larger feeds than
you do.

I wouldn\'t be so sure of that. My recollection is that domestic power in
several European countries is very much lower than in the UK with a 20A
main fuse being common in rural areas. Same when I lived in Japan too.

Spain is peculiar in that we have to pay for the size of that fuse. Not
an actual fuse, it is an electronic limiter inside the smart meter, and
can be configured remotely. The minimum currently is 2.3KW, and the
maximum is 15 KW, for a home. But you can contract thryphasic, and
triple that power. Commercial users have different rules.

Thus, people reduce the power capacity in their contract and
corresponding fuse, because it is not cheap.

Having the grid capacity so that everyone is guaranteed to be able
to draw 100 A at the same time (that is the legal meaning here, as
everybody would have a contract to do just that) means the grid
needs that capacity, which is expensive - even if they sit at 1 A
the rest of the day.

No one with any intelligence designs a grid like that.  Here, we have
a transformer shared by two to four houses.  They don\'t even size
that to allow all the houses sharing the transformer to run full tilt
continuously.  They understand the statistical nature of energy
usage... other than a commercials in a football game.

You (Ricky) can not judge if what others do is intelligent or not. They
have their reasons, different than yours.

I\'m simply trying to point out that not every country is like yours,
that there are many ways of doing things. You are probably living in a
privileged country where energy and energy capacity are cheap.

They rely on diversity of use. An assumption that is broken around
evening meal times and especially at half time of major sporting events.
UK National Grid is offering people with smart meters an incentive not
to run heavy loads at peak times during this winter.

Exactly.

What they are doing here is raise the price during peak hours.

Oh, I forgot: we now can contract different current limit during
peak/valley hours. Say limit to 15A during peak hours, 25A during valley
hours. The pricing is also different.

Unclear if it will work my electricity supplier isn\'t taking part

Fortunately peak load per household seldom exceeds 10A at the same time
so the distribution network is never under threat.
What is stupid is refusing to understand that the world doesn\'t
follow the same customs and ways as your country. There are
different ways out there, and getting angry when someone simply
tells you of the differences.

No one is angry.  I\'m  just pointing out that much of what you write
is inconsistent and clearly erroneous.   If you don\'t understand your
grid, I don\'t expect you to be able to explain it.

He is describing the sort of mains power that is quite common in Spain,
Italy and a few other southern European countries and Japan too.

Exactly.

Belgium
by comparison had about the same fusing as in the UK - in fact their
phone connectors also looked like they were rated for about 10A!

https://nl.forum.proximus.be/archieven-2010-2017-44/internet-valt-weg-bij-gebruik-vaste-telefoon-41593

Wow

For scale the round pins are ~3mm diameter the whole thing 2\" square.
They were mostly a sort of weird oval shape when I lived there.

--
Cheers, Carlos.

 

[Carlos E.R.]

On 2022-11-18 11:23, Martin Brown wrote:

On 17/11/2022 19:18, Ricky wrote:
On Thursday, November 17, 2022 at 2:12:13 PM UTC-5, Carlos E.R.
wrote:
On 2022-11-17 17:12, Ricky wrote:
On Thursday, November 17, 2022 at 8:39:52 AM UTC-5, Martin Brown
wrote:
...
And why do people say it costs thousands of dollars to
fit something to do this? Surely a 10kW invertor doesn\'t
cost much, just something to make 400VDC into 240VAC. I\'d
say more like 500 dollars.

Yep, a couple of quid for the battery, a few more quid for
the casing, employ some untrained monkey on minimum wage to
fit it to the grid with bell wire, a small inverter and a
suicide lead to plug it back into a convenient 3 pin socket
when the backup is needed.

What battery? The battery is already in the car. All you need
is a convertor from 400VDC to 240VAC, and if you want it
automated, a big contactor to switch to the car and back.
A Tesla powerwall battery ~14kWh intended for home use has an
inverter that can only output about 7kW peak and 5kW
continuous.

https://electrek.co/2021/04/22/tesla-increasing-powerwall-power-capacity/



Yeah, they are a bit limited too. Try using one as your primary backup.
When it kicks in, your electric use is suddenly limited.
Mine would be more than doubled. A typical home here has 3.6 or 4.8
KW max.

3.6 kW is only 15A at 240V.  I\'m told that in the UK, when an
important football game is on, there\'s a power surge from the 9 amp
kettles going on during commercials.  I guess where you live, they

Half time at a major sporting event is a major coherent spike in grid
power usage and they need to be ready for it.

They are not 9A kettles either. The typical UK kettle now is 2.4kW/10A
although many older kettles like mine are 3kW/13A. The maximum load that
a nominal 13A socket can take continuously has been recently downgraded.

Too many cheap and nasty Chinese ones melted with continuous 13A loads.
Notably with increased use of 3kW fan heaters to heat a single room
(causing other problems as well in this energy crisis).

https://metro.co.uk/2022/11/15/cost-of-living-crisis-fire-safety-warning-over-electric-heaters-17753200/

Becoming a problem right now as rising energy prices mean people turn
off CH and heat just one room with an old electric fan heater to save
money. Older ones are invariably 3kW and the modern \"13A\" sockets are
made down to a price and not really up to it. Once they start to fail by
overheating the damage quickly becomes exponentially bad.

Warming up a room from cold with a solid 3kW 13A continuous load
stresses some sockets beyond the point where they become serious hot
after an hour or so.

Me, I refuse to run a heater at more than 1 KW. 2 KW if the room is very
cold and nothing big is using electricity at the same time. Yes, it will
take longer to warm up, but it gets there (not talking of my house).

But it is difficult to find a heater of less than 2 KW, which is weird
considering the typical max power of houses here. Perhaps it is a
conspiracy by manufacturers to make us contract more power and make the
grid owners rich

have to turn off the TV to run the kettle.  Or maybe they unplug the
refrigerator?

When we lived in Japan it was the same. A kettle was a thermally
insulated vessel that kept water near ready to use temperature and
consumed energy 24/7 to keep it that way. It took forever to get hot
boiling water after refilling it with just 500W peak consumption. You
gave it a boost to go from 90+C to boiling prior to use.

I have not seen those kettles here. Now that I think, I saw one in
Lancaster, long ago, at an YMCA place :-D

It was big and hooked on the wall, to make tea for many people and fast.

Me, I use a thick iron pot on the induction range to make tea. Quite
fast, I barely have time to prepare the strainer with the leaves.

https://images.app.goo.gl/TKS8FR2a26ezf53B9

Like that one, but cheaper.

Having aircon, immersion heater and washing machine on at the same time
would take out the MCB for overload. We found that out the hard way.

Indeed.

ISTR In Europe Spain, Greece and Italy have rather feeble domestic supply.

UK mains is traditionally something like 40A (1950\'s build) increasing
by about 20A for every few decades since. My house fuse is 60A I tried
to sweet talk the engineer into putting in an electric car ready 100A
fuse when he replaced the meter recently but they aren\'t allowed to.

No technical reason why not - electric company charges for the upgrade
to 100A whereas meter replacement is free.

Where exactly is \"here\"?

Spain or Italy at a guess. Greece is (was?) similar.

My address says Spain ;-)

>

--
Cheers, Carlos.

 

[Carlos E.R.]

On 2022-11-18 11:37, Martin Brown wrote:

On 17/11/2022 19:00, Ricky wrote:
On Thursday, November 17, 2022 at 11:59:31 AM UTC-5, Joe Gwinn
wrote:

....

My house has 100 amp service. But we have a gas stove and water
heater, and oil heat. No electric heat. My shop runs off 220 Vac, but
the big machines are only used intermittently, but will need a
lot of power when doing something heavy.

Do you have a 240V to 220V transformer?  If not, you have excessive
voltage drop coming to your house and should ask the power company to
fix that.

UK says it has 240v but in reality all of Europe uses a ~230v nominal
voltage with an asymmetric tolerance band see for example:

www.spenergynetworks.co.uk/pages/voltage_changes.aspx#:~:text=declared,216.2%20volts%20to%20253.0%20volts.

Yes, Spain silently changed from 220 to 230. They said nothing, but it
was in the fine print of the contract. I believe the EU standardized on 230.

--
Cheers, Carlos.

 

[John Larkin]

On Fri, 18 Nov 2022 10:37:40 +0000, Martin Brown
<\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 17/11/2022 19:00, Ricky wrote:
On Thursday, November 17, 2022 at 11:59:31 AM UTC-5, Joe Gwinn
wrote:
On Thu, 17 Nov 2022 13:39:36 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

10kW is a fairly reasonable figure for powering a home. Over
engineering it to do 20kW or 40kW continuous would not be good
value for money.
In the UK, perhaps. In the US, lots of homes have gone to 100-amp
220 Vac split phase, or 22 KW. Some have twice that.

No home in the US have gone to 100-amp, 220VAC split phase. The
nominal voltage in the US is 240V. I expect very few homes in the US
have been built with 100 amp service in the last 50 years. In the
70s, there was a big push to use more electric appliances, including
electric radiant heat! You aren\'t getting that with 100 amp
service.

Since US domestic power is nominal 110v I\'d have thought that 100A per
live feed was about right (bordering on the low side). OTOH high power
devices like aircon are run phase to phase on 220v.

I typically measure 122 at work or home.

Our house is 120-n-120 at 100 amps per phase. That\'s huge, since we
use gas for heat and cooking and we don\'t have a/c.

Only the clothes dryer uses 240.

 

[Lasse Langwadt Christensen]

fredag den 18. november 2022 kl. 11.37.56 UTC+1 skrev Martin Brown:

On 17/11/2022 19:00, Ricky wrote:
On Thursday, November 17, 2022 at 11:59:31 AM UTC-5, Joe Gwinn
wrote:
On Thu, 17 Nov 2022 13:39:36 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

10kW is a fairly reasonable figure for powering a home. Over
engineering it to do 20kW or 40kW continuous would not be good
value for money.
In the UK, perhaps. In the US, lots of homes have gone to 100-amp
220 Vac split phase, or 22 KW. Some have twice that.

No home in the US have gone to 100-amp, 220VAC split phase. The
nominal voltage in the US is 240V. I expect very few homes in the US
have been built with 100 amp service in the last 50 years. In the
70s, there was a big push to use more electric appliances, including
electric radiant heat! You aren\'t getting that with 100 amp
service.

Since US domestic power is nominal 110v I\'d have thought that 100A per
live feed was about right (bordering on the low side). OTOH high power
devices like aircon are run phase to phase on 220v.

My feed is 60A @ 230v ~ 14kW modern build here would be 100A ~ 23kW

I live in an apartment, I don\'t know what the feed is but in my panel is 4*10A fuses

Base load 24/7 is 70W typical daytime load ~300W peak maybe 6kW.
My house has 100 amp service. But we have a gas stove and water
heater, and oil heat. No electric heat. My shop runs off 220 Vac,
but the big machines are only used intermittently, but will need a
lot of power when doing something heavy.

Do you have a 240V to 220V transformer? If not, you have excessive
voltage drop coming to your house and should ask the power company to
fix that.
UK says it has 240v but in reality all of Europe uses a ~230v nominal
voltage with an asymmetric tolerance band see for example:

www.spenergynetworks.co.uk/pages/voltage_changes.aspx#:~:text=declared,216.2%20volts%20to%20253.0%20volts.

I believe it has been changed to a symmetric +/-10%

Most appliances (including air conditioners) are 120 Vac and 15 or
20 amps. Things like clothes dryers are 220 Vac. Many people have
electric water heaters. also 220 Vac.

If you have 120V on the low voltage outlets, how do you get 220V on
the high voltage circuits? Is your line not balanced with one at
120V and the other at 100V?
It is likely that as in the UK confusion reigns about actual mains
voltage - so few consumers ever measure it and think they have 240v. It
could in reality be as low as 216 or high as 253 and still (just) in spec.

In most of Europe it is likely to be 230v nominal 115v-0-115v balanced
or it could be full three phase supply to industrial premises.

here (Denmark) everyone has three phase

 

[Ricky]

On Friday, November 18, 2022 at 6:38:59 AM UTC-5, Ed Lee wrote:

On Friday, November 18, 2022 at 3:17:18 AM UTC-8, Martin Brown wrote:
On 18/11/2022 01:36, Ed Lee wrote:
On Thursday, November 17, 2022 at 5:30:44 PM UTC-8, Ricky wrote:
On Thursday, November 17, 2022 at 8:18:50 PM UTC-5, Ed Lee wrote:
On Thursday, November 17, 2022 at 5:00:38 PM UTC-8, Fred Bloggs wrote:
On Thursday, November 17, 2022 at 3:58:36 PM UTC-5, John Larkin wrote:
On Thu, 17 Nov 2022 10:32:33 -0800 (PST), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

On Thursday, November 17, 2022 at 10:30:31 AM UTC-5, John Larkin wrote:
On Thu, 17 Nov 2022 05:03:57 -0800 (PST), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

On Thursday, November 17, 2022 at 4:27:46 AM UTC-5, Commander Kinsey wrote:
If an EV has an output power of say 80kW to drive the motors when driving, why is the backup power (to power your house in a power outage) only about 10kW? It\'s the same battery!

And why do people say it costs thousands of dollars to fit something to do this? Surely a 10kW invertor doesn\'t cost much, just something to make 400VDC into 240VAC. I\'d say more like 500 dollars.

You need to learn the difference between energy and power. The 80kW is really 80kWh(hours), a measure of energy stored in the battery. The 10kW is a measure of power which is the rate of energy extraction from the battery, usually specified in kW, kilo-watts, thousands of Watts. There is no logical connection between the two ratings. The engineering requirements of the battery EV application determines that.

He clearly said that the battery can deliver 80 KW of power. No 80 KWH
car is going to be limited to 10 KW into the motors. Ecars are all
about acceleration.

That 80kW is quoted quite often as the battery capacity when they mean 80kWh of course. Without that as his fundamental misunderstanding, the question is senseless.
The misunderstanding was yours. The nastiness too.
I have no misunderstanding. The manufacturers don\'t specify the \"drive power\" of the batteries in their EV. Why would the consumer need to know that? They do specify battery capacity of their EV because it gives the consumer an idea of expected range.
3 miles per kwhr is a good rule of thumb. So, if you need to drive 60MPH, then you need around 20kW drive power. I don\'t know why people need 150kW, unless they are driving 450MPH.
3 miles per kWh is a good number for an electron guzzler like my X. The less bloated cars like the 3 and Y get more like 4 miles per kWh and I\'d lump the Nissan Leaf into 4 miles per kWh group from everything I\'ve heard.

So, 150kW drive power can get up to 600MPH.
Air resistance causes drag forces which robs power as the cube of
velocity becomes distinctly non-negligible from 60mph upwards so you are
being rather over optimistic there.

https://en.wikipedia.org/wiki/Drag_(physics)

The 80kW or 150kW is so they can claim 100Hp or 180Hp and have 0-60
times that are in the supercar league. It tends to wear the tyres out if
you spend too much time going from 0 to 60mph in the shortest time.
That\'s my point exactly. Anything over 50kW drive (motor) is just theoretical (marketing).

The carmakers put lots of power in a car, so they can pass on hills and such. It has been more than once I\'ve put my foot on the floor to pass a car.

--

Rick C.

--+- Get 1,000 miles of free Supercharging
--+- Tesla referral code - https://ts.la/richard11209

 

[Ricky]

On Friday, November 18, 2022 at 6:47:12 AM UTC-5, Martin Brown wrote:

On 18/11/2022 11:08, Ricky wrote:
On Friday, November 18, 2022 at 5:36:14 AM UTC-5, Carlos E.R. wrote:
On 2022-11-18 02:23, Ricky wrote:
On Thursday, November 17, 2022 at 8:00:13 PM UTC-5, Carlos E.R.
wrote:
On 2022-11-18 01:20, Ricky wrote:
On Thursday, November 17, 2022 at 4:36:12 PM UTC-5, Carlos
E.R. wrote:
On 2022-11-17 21:34, Ricky wrote:
That and heat pump heating are the top of the list for
power draw. Even without those, my small family house
built in the early \'60s had 100 amp service. I can\'t
imagine all the juggling I\'d have to do to keep under 15
amps at all times. Heck, my hot water heater draws
something like 17-18 amps, which is churning away at the
moment because I just got out of a hot shower.

My 50l hot water tank is 1KW (actually, I put a diode in
series to lower it by half). A 300 litres unit, for eight
people, takes 3 KW. If you have such a big house, normally
you would contract for more electricity.

Yes, that is my point. Your 3.6 kW house is a bit of an
outlier.
On the contrary, 3.6 is typical, on flats (the majority of the
people here live in flats). Mine is just 2.4.

I\'m sorry, 2.4 kW is just 10 amps at 240V. Now you really are in
Green Acres territory. I never realized Spain was this way.

You are getting it wrong. It is not Spain, it is this house.

You seem to be inconsistent. I say you are an outlier, and you say,
no, this is common. Now you say it\'s just this house.

I\'ve reached the point of not caring. You don\'t have a point to
make. You just want to talk in circles.

I have no doubt that 99% of the population has much larger feeds than
you do.
I wouldn\'t be so sure of that. My recollection is that domestic power in
several European countries is very much lower than in the UK with a 20A
main fuse being common in rural areas. Same when I lived in Japan too.

He has said both that these low home power connections are typical, then said \"It is not Spain, it is this house.\" Am I misunderstanding what he is saying?

I don\'t really care one way or the other. If a country wants to ration electrical power and play Green Acres with everyone\'s power connection, it has no impact on me and I have no impact on it.

Having the grid capacity so that everyone is guaranteed to be able
to draw 100 A at the same time (that is the legal meaning here, as
everybody would have a contract to do just that) means the grid
needs that capacity, which is expensive - even if they sit at 1 A
the rest of the day.

No one with any intelligence designs a grid like that. Here, we have
a transformer shared by two to four houses. They don\'t even size
that to allow all the houses sharing the transformer to run full tilt
continuously. They understand the statistical nature of energy
usage... other than a commercials in a football game.
They rely on diversity of use. An assumption that is broken around
evening meal times and especially at half time of major sporting events.
UK National Grid is offering people with smart meters an incentive not
to run heavy loads at peak times during this winter.

That\'s everywhere. All electrical grids have peak power usage each day. What he is talking about is not being able to cook when you want because the hot water heater and the A/C are both running. His entire home is on a 10 amp circuit!!!

Unclear if it will work my electricity supplier isn\'t taking part

Fortunately peak load per household seldom exceeds 10A at the same time
so the distribution network is never under threat.

He said they don\'t use electricity for heating and the A/C is just 1 kW for one room. So he is living like a third world country. That\'s how many places are in Puerto Rico. The last place I stayed had a low water use flapper valve on the toilet. It was so bad, the damn thing would not flush properly. They had to call a plumber to clean it out. Penny wise, pound foolish.

What is stupid is refusing to understand that the world doesn\'t
follow the same customs and ways as your country. There are
different ways out there, and getting angry when someone simply
tells you of the differences.

No one is angry. I\'m just pointing out that much of what you write
is inconsistent and clearly erroneous. If you don\'t understand your
grid, I don\'t expect you to be able to explain it.
He is describing the sort of mains power that is quite common in Spain,
Italy and a few other southern European countries and Japan too. Belgium
by comparison had about the same fusing as in the UK - in fact their
phone connectors also looked like they were rated for about 10A!

He is not being consistent in what he says.

The rest is just noise.

--

Rick C.

--++ Get 1,000 miles of free Supercharging
--++ Tesla referral code - https://ts.la/richard11209

 

[ke...@kjwdesigns.com]

On Thursday, 17 November 2022 at 01:27:46 UTC-8, Commander Kinsey wrote:

If an EV has an output power of say 80kW to drive the motors when driving, why is the backup power (to power your house in a power outage) only about 10kW? It\'s the same battery!

And why do people say it costs thousands of dollars to fit something to do this? Surely a 10kW invertor doesn\'t cost much, just something to make 400VDC into 240VAC. I\'d say more like 500 dollars.

Five hundred Dollars is rather optimistic - more like $2-5K for a 10kW inverter.

For example:

https://shopsolarkits.com/collections/solar-power-inverters?custom=Product%20Type

kw

 

[Ricky]

On Friday, November 18, 2022 at 7:36:13 AM UTC-5, Carlos E.R. wrote:

On 2022-11-18 12:46, Martin Brown wrote:
On 18/11/2022 11:08, Ricky wrote:
On Friday, November 18, 2022 at 5:36:14 AM UTC-5, Carlos E.R. wrote:
On 2022-11-18 02:23, Ricky wrote:
On Thursday, November 17, 2022 at 8:00:13 PM UTC-5, Carlos E.R.
wrote:
On 2022-11-18 01:20, Ricky wrote:
On Thursday, November 17, 2022 at 4:36:12 PM UTC-5, Carlos
E.R. wrote:
On 2022-11-17 21:34, Ricky wrote:
That and heat pump heating are the top of the list for
power draw. Even without those, my small family house
built in the early \'60s had 100 amp service. I can\'t
imagine all the juggling I\'d have to do to keep under 15
amps at all times. Heck, my hot water heater draws
something like 17-18 amps, which is churning away at the
moment because I just got out of a hot shower.

My 50l hot water tank is 1KW (actually, I put a diode in
series to lower it by half). A 300 litres unit, for eight
people, takes 3 KW. If you have such a big house, normally
you would contract for more electricity.

Yes, that is my point. Your 3.6 kW house is a bit of an
outlier.
On the contrary, 3.6 is typical, on flats (the majority of the
people here live in flats). Mine is just 2.4.

I\'m sorry, 2.4 kW is just 10 amps at 240V. Now you really are in
Green Acres territory. I never realized Spain was this way.

You are getting it wrong. It is not Spain, it is this house.

You seem to be inconsistent. I say you are an outlier, and you say,
no, this is common. Now you say it\'s just this house.
Or you (Ricky) have some reading problems.

I said the typical home here has a 3.6 KW contract and limit.

I also said that mine is just 2.4 KW contract and limit, and is not a
small house. It is significantly bigger than the average. You might ask
(politely) why I have such a small pipe, or not. But do not assume
things that you do not know.

You have had several opportunities to explain the matter, yet you go back and forth. I don\'t know how to get a straight answer from you. It doesn\'t matter. I have no interest in living like I\'m in a third world country. I see this sort of thing in Puerto Rico all the time. They get a mind set that electricity is expensive, so they freak out about leaving a light on, a light that has to be on for 400 hours to cost $1.00. People tend to not actually pay attention to the facts, they just shoot from the hip.

I\'ve reached the point of not caring. You don\'t have a point to
make. You just want to talk in circles.

I have no doubt that 99% of the population has much larger feeds than
you do.

I wouldn\'t be so sure of that. My recollection is that domestic power in
several European countries is very much lower than in the UK with a 20A
main fuse being common in rural areas. Same when I lived in Japan too.
Spain is peculiar in that we have to pay for the size of that fuse. Not
an actual fuse, it is an electronic limiter inside the smart meter, and
can be configured remotely. The minimum currently is 2.3KW, and the
maximum is 15 KW, for a home. But you can contract thryphasic, and
triple that power. Commercial users have different rules.

Thus, people reduce the power capacity in their contract and
corresponding fuse, because it is not cheap.

That\'s a problem of mindset. There is literally no reason for the power company to charge so much for even a tiny feed. You have acclimated and are happy living at Green Acres. Lisa also adapted, because she wanted to be with her husband. Great for you.

Having the grid capacity so that everyone is guaranteed to be able
to draw 100 A at the same time (that is the legal meaning here, as
everybody would have a contract to do just that) means the grid
needs that capacity, which is expensive - even if they sit at 1 A
the rest of the day.

No one with any intelligence designs a grid like that. Here, we have
a transformer shared by two to four houses. They don\'t even size
that to allow all the houses sharing the transformer to run full tilt
continuously. They understand the statistical nature of energy
usage... other than a commercials in a football game.
You (Ricky) can not judge if what others do is intelligent or not. They
have their reasons, different than yours.

And you are not able to explain any of it.

I\'m simply trying to point out that not every country is like yours,
that there are many ways of doing things. You are probably living in a
privileged country where energy and energy capacity are cheap.

Not sure what to make of that. The cost of building and operating power grids does not vary tremendously around the first world. The sort of miserly distribution of power you are talking about is not because of inherent costs. It is because of mindsets.

They rely on diversity of use. An assumption that is broken around
evening meal times and especially at half time of major sporting events..
UK National Grid is offering people with smart meters an incentive not
to run heavy loads at peak times during this winter.
Exactly.

What they are doing here is raise the price during peak hours.

That\'s common everywhere. It\'s also nothing like limiting the size of your \"pipe\".

Oh, I forgot: we now can contract different current limit during
peak/valley hours. Say limit to 15A during peak hours, 25A during valley
hours. The pricing is also different.

15A is 3.6 kW. I thought that was the larger pipe most people have all the time? So there is a need for a larger pipe for those same people, and the power company is willing to provide that at off peak times? Sounds like people being happy with 3.6 kW is bogus.

Unclear if it will work my electricity supplier isn\'t taking part

Fortunately peak load per household seldom exceeds 10A at the same time
so the distribution network is never under threat.
What is stupid is refusing to understand that the world doesn\'t
follow the same customs and ways as your country. There are
different ways out there, and getting angry when someone simply
tells you of the differences.

No one is angry. I\'m just pointing out that much of what you write
is inconsistent and clearly erroneous. If you don\'t understand your
grid, I don\'t expect you to be able to explain it.

He is describing the sort of mains power that is quite common in Spain,
Italy and a few other southern European countries and Japan too.
Exactly.

Except that you continue to change your story.

--

Rick C.

-+-- Get 1,000 miles of free Supercharging
-+-- Tesla referral code - https://ts.la/richard11209