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

[Carlos E.R.]

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.

--
Cheers, Carlos.

 

[Ricky]

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

They don\'t list an electric range.

--

Rick C.

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

 

[Ricky]

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

Where exactly is \"here\"?

--

Rick C.

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

 

[Carlos E.R.]

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\".

>

--
Cheers, Carlos.

 

[Ralph Mowery]

In article <c4eadc5b-ff7c-4ffc-8fb4-1bdc2f976a70n@googlegroups.com>,
gnuarm.deletethisbit@gmail.com says...

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.


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?

--

He is probably like me. Says 110 and 120 or 220 and 240 at different
times when he talks about the low or higher voltage.

Over the years in the US the voltage went from 110/220 to 115/230 to
120/240. There was even some 117 volts. People as old as I am remember
their dads talking about 110/220 so sometimes they may say any of the
above.

Now most of the time my voltage is 125/250, sometimes even more. This
was measured with 2 different Fluke meters that had been calibrated at
a seperate test lab.

 

[Ricky]

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). 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? 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.

I\'ve noticed that in Puerto Rico the circuit breakers are all 20 amps. I don\'t know that they have the larger wire in the walls. But the only harm overheating can do is to the wiring itself, so maybe that\'s not an issue, concrete walls. I have not noticed that the outlets are 20 amps. But even there, they have a lot more than 3.6 kW to a house. Heck, one 20 amp circuit is 4.8 kW if run at the breaker limit.

--

Rick C.

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

 

[Ed Lee]

On Thursday, November 17, 2022 at 8:12:48 AM UTC-8, Ricky wrote:

On Thursday, November 17, 2022 at 8:39:52 AM UTC-5, Martin Brown 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.

It is enough for 2x 3kW fan heaters and a 3kW immersion heater with a
bit to spare for electric lighting and gadgets.
EVs require a larger battery because the owner can only drive 4 miles
for every kWh of battery (on a good day).
The other thing is that when an EV is moving at speed there is much
better cooling airflow around the vehicle and its batteries. Maximum
sustained power output will be reduced when the vehicle is stationary.
You might think that applies to charging as well, which is typically done with the car stationary. Yet charging is done at power levels much higher than the typical 15-20 kW a car uses. Even on steep upgrades or when passing it\'s seldom my car uses over 150 kW.

Even that is a lot.

If i drive at 60MPH for an hour, i burn 20kWhr. So, average is 20kW. My motor is 80kW, but usually 30 to 40kW to accelerate.

 

[Ricky]

On Thursday, November 17, 2022 at 3:26:27 PM UTC-5, Ralph Mowery wrote:

In article <c4eadc5b-ff7c-4ffc...@googlegroups.com>,
gnuarm.del...@gmail.com says...


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.


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?

--


He is probably like me. Says 110 and 120 or 220 and 240 at different
times when he talks about the low or higher voltage.

Over the years in the US the voltage went from 110/220 to 115/230 to
120/240. There was even some 117 volts. People as old as I am remember
their dads talking about 110/220 so sometimes they may say any of the
above.

Now most of the time my voltage is 125/250, sometimes even more. This
was measured with 2 different Fluke meters that had been calibrated at
a seperate test lab.

The only time I\'ve seen 117V was on appliance rating plates. As far back as I can remember (including my teenage years) the nominal household outlet voltage was 120V. I believe 120V was the official standard in 1967. That was a long time ago. I think it\'s time to forgive and forget!

--

Rick C.

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

 

[John Larkin]

On Thu, 17 Nov 2022 10:32:33 -0800 (PST), Fred Bloggs
<bloggs.fredbloggs.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.

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.

Battery cooling could be involved too, for a parked car.

 

[Carlos E.R.]

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.

> 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.

> 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.

<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.

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.

I\'ve noticed that in Puerto Rico the circuit breakers are all 20 amps. I don\'t know that they have the larger wire in the walls. But the only harm overheating can do is to the wiring itself, so maybe that\'s not an issue, concrete walls. I have not noticed that the outlets are 20 amps. But even there, they have a lot more than 3.6 kW to a house. Heck, one 20 amp circuit is 4.8 kW if run at the breaker limit.

--
Cheers, Carlos.

 

[Ricky]

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.

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..

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.

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.

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.

There\'s some irony that this was the time when nuclear was being built in mass, an energy source that was claimed to be \"too cheap to meter\". Yet it was the start of the rise of the cost of electricity, in the US anyway.

--

Rick C.

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

 

[Carlos E.R.]

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.

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.

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.

There\'s some irony that this was the time when nuclear was being built in mass, an energy source that was claimed to be \"too cheap to meter\". Yet it was the start of the rise of the cost of electricity, in the US anyway.

--
Cheers, Carlos.

 

[Fred Bloggs]

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?

 

[Ed Lee]

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.

 

[Ricky]

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.

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.

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.

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

--

Rick C.

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

 

[Ricky]

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.

--

Rick C.

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

 

[Ricky]

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.

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.

Your Leaf has no battery cooling, right?

--

Rick C.

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

 

[Ed Lee]

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.

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.
Your Leaf has no battery cooling, right?

Not for my #1 battery, but #2 and #3 are A/C cooled.

 

[Fred Bloggs]

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.

 

[Fred Bloggs]

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.

--

Rick C.

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