Australians set to waste money on batteries

[Sylvia Else]

<http://www.abc.net.au/news/2015-05-21/powerwall-solar-batteries-to-transform-electricity-industry/6488230>

http://www.teslamotors.com/en_AU/powerwall

At $5500 (is that including GST?) for a 7kWh model, with a ten year
life, and allowing for interest, that comes in at about 28 cents per
kWh, and that's before the cost of the solar panels and the inverter
(not included with the battery), and installation, is included. It's
also based on the questionable (i.e. certainly false) assumption that
they can be recharged from solar everyday. The reality is that they
won't be, and the cost per kWh will be accordingly higher.

The limit of 2kW continuous and 3.3kW peak should also be noted. It
isn't clear how long one can draw 3.3kW for, but 2kW is less than is
required to run an ordinary domestic kettle. A typical household might
have trouble using the entire capacity, pushing up the effective cost
per kWh.

The good thing about these is that they may finally force a change to
the way electricity is charged for, with much greater emphasis placed on
the cost of making it available versus the cost of supplying it when
it's required. People who treat the grid as a backup will then pay
something closer to the true cost of using it that way.

Either way, I'll have to look at that the economics of charging these on
overnight off-peak power (generated by coal fired power stations) for
use during the evening peak when the much more expensive power would
otherwise be generated using less polluting natural gas, or even hydro.

Sylvia.

 

[Trevor Wilson]

On 22/05/2015 12:12 PM, Sylvia Else wrote:

http://www.abc.net.au/news/2015-05-21/powerwall-solar-batteries-to-transform-electricity-industry/6488230


http://www.teslamotors.com/en_AU/powerwall

At $5500 (is that including GST?) for a 7kWh model, with a ten year
life, and allowing for interest, that comes in at about 28 cents per
kWh, and that's before the cost of the solar panels and the inverter
(not included with the battery), and installation, is included. It's
also based on the questionable (i.e. certainly false) assumption that
they can be recharged from solar everyday. The reality is that they
won't be, and the cost per kWh will be accordingly higher.

The limit of 2kW continuous and 3.3kW peak should also be noted. It
isn't clear how long one can draw 3.3kW for, but 2kW is less than is
required to run an ordinary domestic kettle. A typical household might
have trouble using the entire capacity, pushing up the effective cost
per kWh.

The good thing about these is that they may finally force a change to
the way electricity is charged for, with much greater emphasis placed on
the cost of making it available versus the cost of supplying it when
it's required. People who treat the grid as a backup will then pay
something closer to the true cost of using it that way.

Either way, I'll have to look at that the economics of charging these on
overnight off-peak power (generated by coal fired power stations) for
use during the evening peak when the much more expensive power would
otherwise be generated using less polluting natural gas, or even hydro.

Sylvia.

**A couple of points and questions:

* How do you arrive at 28c/kWh? Please show your calculations.
* A 7kWh model is way too small for most households, except for
emergency situations.
* Li-Ion batteries are close to being wiped out by new developments in
aluminium battery technology. Such technology is likely to be:

* Significantly cheaper.
* Capable of many more charge/discharge cycles.
* Much safer.
* Somewhat more energy dense.

http://news.stanford.edu/news/2015/march/aluminum-ion-battery-033115.html

http://www.nature.com/nature/journal/v520/n7547/full/nature14340.html



--
Trevor Wilson
www.rageaudio.com.au

---
This email has been checked for viruses by Avast antivirus software.
http://www.avast.com

 

[Sylvia Else]

On 22/05/2015 2:24 PM, Trevor Wilson wrote:

On 22/05/2015 12:12 PM, Sylvia Else wrote:
http://www.abc.net.au/news/2015-05-21/powerwall-solar-batteries-to-transform-electricity-industry/6488230



http://www.teslamotors.com/en_AU/powerwall

At $5500 (is that including GST?) for a 7kWh model, with a ten year
life, and allowing for interest, that comes in at about 28 cents per
kWh, and that's before the cost of the solar panels and the inverter
(not included with the battery), and installation, is included. It's
also based on the questionable (i.e. certainly false) assumption that
they can be recharged from solar everyday. The reality is that they
won't be, and the cost per kWh will be accordingly higher.

The limit of 2kW continuous and 3.3kW peak should also be noted. It
isn't clear how long one can draw 3.3kW for, but 2kW is less than is
required to run an ordinary domestic kettle. A typical household might
have trouble using the entire capacity, pushing up the effective cost
per kWh.

The good thing about these is that they may finally force a change to
the way electricity is charged for, with much greater emphasis placed on
the cost of making it available versus the cost of supplying it when
it's required. People who treat the grid as a backup will then pay
something closer to the true cost of using it that way.

Either way, I'll have to look at that the economics of charging these on
overnight off-peak power (generated by coal fired power stations) for
use during the evening peak when the much more expensive power would
otherwise be generated using less polluting natural gas, or even hydro.

Sylvia.


**A couple of points and questions:

* How do you arrive at 28c/kWh? Please show your calculations.

$5500 over 10 years is $1.50 per day.

3% interest on $5500 is $0.45 per day.

So total of $1.95 per day, for 7kWh, is 28 cents per kWh.

This isn't a full discounted cash-flow analysis, but I doubt it's that
far off.

* A 7kWh model is way too small for most households, except for
emergency situations.

I think the intent is that it be used only during the evening, with
daytime power provided directly by solar.

In terms of capacity, it's perhaps not quite big enough, but from an
economic perspective, and while the grid is available as a backup, it's
better to go too small than too big.

Sylvia.

 

[news13]

On Fri, 22 May 2015 12:12:27 +1000, Sylvia Else wrote:

Either way, I'll have to look at that the economics of charging these on
overnight off-peak power (generated by coal fired power stations) for
use during the evening peak when the much more expensive power would
otherwise be generated using less polluting natural gas, or even hydro.

Maybe in ten years time they might be economical. Lead acid still has the
rest beaten. The problem really is the cost to you of building suck a
system.

Thew other issue is whether your mains supplier will let you do it.

 

[Sylvia Else]

On 22/05/2015 3:43 PM, snafu wrote:

On 22-May-15 1:03 PM, Sylvia Else wrote:
On 22/05/2015 2:24 PM, Trevor Wilson wrote:
On 22/05/2015 12:12 PM, Sylvia Else wrote:
http://www.abc.net.au/news/2015-05-21/powerwall-solar-batteries-to-transform-electricity-industry/6488230





http://www.teslamotors.com/en_AU/powerwall

At $5500 (is that including GST?) for a 7kWh model, with a ten year
life, and allowing for interest, that comes in at about 28 cents per
kWh, and that's before the cost of the solar panels and the inverter
(not included with the battery), and installation, is included. It's
also based on the questionable (i.e. certainly false) assumption that
they can be recharged from solar everyday. The reality is that they
won't be, and the cost per kWh will be accordingly higher.

The limit of 2kW continuous and 3.3kW peak should also be noted. It
isn't clear how long one can draw 3.3kW for, but 2kW is less than is
required to run an ordinary domestic kettle. A typical household might
have trouble using the entire capacity, pushing up the effective cost
per kWh.

The good thing about these is that they may finally force a change to
the way electricity is charged for, with much greater emphasis
placed on
the cost of making it available versus the cost of supplying it when
it's required. People who treat the grid as a backup will then pay
something closer to the true cost of using it that way.

Either way, I'll have to look at that the economics of charging
these on
overnight off-peak power (generated by coal fired power stations) for
use during the evening peak when the much more expensive power would
otherwise be generated using less polluting natural gas, or even hydro.

Sylvia.


**A couple of points and questions:

* How do you arrive at 28c/kWh? Please show your calculations.

$5500 over 10 years is $1.50 per day.

3% interest on $5500 is $0.45 per day.

Lose a DP maybe?

0.03 x $5500 = $165

$165 / 10yr x 365days = $0.045 / day

No, the $165 is incurred each year, so you don't divide it by 10.

$1.545 / 7kWh = $0.22 / kWh

 

[Sylvia Else]

On 22/05/2015 3:38 PM, news13 wrote:

On Fri, 22 May 2015 12:12:27 +1000, Sylvia Else wrote:


Either way, I'll have to look at that the economics of charging these on
overnight off-peak power (generated by coal fired power stations) for
use during the evening peak when the much more expensive power would
otherwise be generated using less polluting natural gas, or even hydro.

Maybe in ten years time they might be economical. Lead acid still has the
rest beaten. The problem really is the cost to you of building suck a
system.

Though I don't know of a lead-acid battery that will survive a daily
deep cycle for ten years.

Thew other issue is whether your mains supplier will let you do it.

I don't know that they have a legal basis for objecting.

Sylvia.

 

[snafu]

On 22-May-15 5:11 PM, Sylvia Else wrote:

On 22/05/2015 3:43 PM, snafu wrote:
On 22-May-15 1:03 PM, Sylvia Else wrote:
On 22/05/2015 2:24 PM, Trevor Wilson wrote:
On 22/05/2015 12:12 PM, Sylvia Else wrote:
http://www.abc.net.au/news/2015-05-21/powerwall-solar-batteries-to-transform-electricity-industry/6488230






http://www.teslamotors.com/en_AU/powerwall

At $5500 (is that including GST?) for a 7kWh model, with a ten year
life, and allowing for interest, that comes in at about 28 cents per
kWh, and that's before the cost of the solar panels and the inverter
(not included with the battery), and installation, is included. It's
also based on the questionable (i.e. certainly false) assumption that
they can be recharged from solar everyday. The reality is that they
won't be, and the cost per kWh will be accordingly higher.

The limit of 2kW continuous and 3.3kW peak should also be noted. It
isn't clear how long one can draw 3.3kW for, but 2kW is less than is
required to run an ordinary domestic kettle. A typical household might
have trouble using the entire capacity, pushing up the effective cost
per kWh.

The good thing about these is that they may finally force a change to
the way electricity is charged for, with much greater emphasis
placed on
the cost of making it available versus the cost of supplying it when
it's required. People who treat the grid as a backup will then pay
something closer to the true cost of using it that way.

Either way, I'll have to look at that the economics of charging
these on
overnight off-peak power (generated by coal fired power stations) for
use during the evening peak when the much more expensive power would
otherwise be generated using less polluting natural gas, or even
hydro.

Sylvia.


**A couple of points and questions:

* How do you arrive at 28c/kWh? Please show your calculations.

$5500 over 10 years is $1.50 per day.

3% interest on $5500 is $0.45 per day.

Lose a DP maybe?

0.03 x $5500 = $165

$165 / 10yr x 365days = $0.045 / day

No, the $165 is incurred each year, so you don't divide it by 10.

Yes, of course!

$1.545 / 7kWh = $0.22 / kWh

 

[Trevor Wilson]

On 22/05/2015 7:31 PM, Sylvia Else wrote:

On 22/05/2015 3:38 PM, news13 wrote:
On Fri, 22 May 2015 12:12:27 +1000, Sylvia Else wrote:


Either way, I'll have to look at that the economics of charging these on
overnight off-peak power (generated by coal fired power stations) for
use during the evening peak when the much more expensive power would
otherwise be generated using less polluting natural gas, or even hydro.

Maybe in ten years time they might be economical. Lead acid still has the
rest beaten. The problem really is the cost to you of building suck a
system.

Though I don't know of a lead-acid battery that will survive a daily
deep cycle for ten years.

**They exist. Back when I worked for OTC, the battery rooms most of the
stations contained row upon row of huge, Pyrex™, lead/acid batteries.
They were designed to run an international telephone exchange several
hours, but preferably just long enough for the Diesel generators to
power up. In the Paddington exchange, the battery room had a 2 Tonne
fire door and half dozen 2 Metre high cylinders of CO2. In the event of
excessive H2, or a fire, the door would close automatically and the room
was flooded with CO2. Anyway, the batteries were not only designed to
last a very long time, but, in the event that a cell failed, it could be
relatively easily repaired. Of course, back then, OTC was awash with
cash and the hugely expensive batteries could be justified.

Thew other issue is whether your mains supplier will let you do it.


I don't know that they have a legal basis for objecting.

**Of course not. There is no reason why such a system could not be employed.


--
Trevor Wilson
www.rageaudio.com.au

---
This email has been checked for viruses by Avast antivirus software.
http://www.avast.com

 

[Sylvia Else]

On 23/05/2015 7:26 AM, Trevor Wilson wrote:

On 22/05/2015 7:31 PM, Sylvia Else wrote:
On 22/05/2015 3:38 PM, news13 wrote:
On Fri, 22 May 2015 12:12:27 +1000, Sylvia Else wrote:


Either way, I'll have to look at that the economics of charging
these on
overnight off-peak power (generated by coal fired power stations) for
use during the evening peak when the much more expensive power would
otherwise be generated using less polluting natural gas, or even hydro.

Maybe in ten years time they might be economical. Lead acid still has
the
rest beaten. The problem really is the cost to you of building suck a
system.

Though I don't know of a lead-acid battery that will survive a daily
deep cycle for ten years.

**They exist. Back when I worked for OTC, the battery rooms most of the
stations contained row upon row of huge, Pyrex™, lead/acid batteries.
They were designed to run an international telephone exchange several
hours, but preferably just long enough for the Diesel generators to
power up. In the Paddington exchange, the battery room had a 2 Tonne
fire door and half dozen 2 Metre high cylinders of CO2. In the event of
excessive H2, or a fire, the door would close automatically and the room
was flooded with CO2. Anyway, the batteries were not only designed to
last a very long time, but, in the event that a cell failed, it could be
relatively easily repaired. Of course, back then, OTC was awash with
cash and the hugely expensive batteries could be justified.

Sounds like the requirement was for batteries that that could left fully
charged almost all of the time, and only cycled infrequently, which is
rather different from the situation under discussion.

Sylvia.

 

[news13]

On Fri, 22 May 2015 19:31:51 +1000, Sylvia Else wrote:

On 22/05/2015 3:38 PM, news13 wrote:
On Fri, 22 May 2015 12:12:27 +1000, Sylvia Else wrote:


Either way, I'll have to look at that the economics of charging these
on overnight off-peak power (generated by coal fired power stations)
for use during the evening peak when the much more expensive power
would otherwise be generated using less polluting natural gas, or even
hydro.

Maybe in ten years time they might be economical. Lead acid still has
the rest beaten. The problem really is the cost to you of building suck
a system.

Though I don't know of a lead-acid battery that will survive a daily
deep cycle for ten years.

Err, never heard of "Deep cycle lead acid battery"?
Twenty years is viable and often achieved.

Like all batteries, each type has % depth, rates and cycle trade offs,
not to mention relative cost.

ABC Science show?, I think, was discussing this "wall" and the guys in
the field just said NOPE, it is just a step on the road to the one we
need. Caveat electric cars.

H

Thew other issue is whether your mains supplier will let you do it.


I don't know that they have a legal basis for objecting.

as an electrician said "I can't do it legally, but there is nothing to
Atop you doing it". I wanted a circuit running off the OP to keep a few
emergency batteries topped up.

I suspect they have some legal say on what is connected to their network.

Sylvia.

 

[news13]

On Sat, 23 May 2015 12:58:28 +1000, Sylvia Else wrote:

On 23/05/2015 7:26 AM, Trevor Wilson wrote:
On 22/05/2015 7:31 PM, Sylvia Else wrote:
On 22/05/2015 3:38 PM, news13 wrote:
On Fri, 22 May 2015 12:12:27 +1000, Sylvia Else wrote:


Either way, I'll have to look at that the economics of charging
these on overnight off-peak power (generated by coal fired power
stations) for use during the evening peak when the much more
expensive power would otherwise be generated using less polluting
natural gas, or even hydro.

Maybe in ten years time they might be economical. Lead acid still has
the rest beaten. The problem really is the cost to you of building
suck a system.

Though I don't know of a lead-acid battery that will survive a daily
deep cycle for ten years.

**They exist. Back when I worked for OTC, the battery rooms most of the
stations contained row upon row of huge, Pyrex™, lead/acid batteries.
They were designed to run an international telephone exchange several
hours, but preferably just long enough for the Diesel generators to
power up. In the Paddington exchange, the battery room had a 2 Tonne
fire door and half dozen 2 Metre high cylinders of CO2. In the event of
excessive H2, or a fire, the door would close automatically and the
room was flooded with CO2. Anyway, the batteries were not only designed
to last a very long time, but, in the event that a cell failed, it
could be relatively easily repaired. Of course, back then, OTC was
awash with cash and the hugely expensive batteries could be justified.

Sounds like the requirement was for batteries that that could left fully
charged almost all of the time, and only cycled infrequently, which is
rather different from the situation under discussion.

Not really; the limitation is a factor of the discharge rates and depth
of discharge. That sort of system is designed to run a major computer
room for 15 minutes whilst thge backup generator is started, run up to
speed and sync'd properly.

Ther major requirment is to detect mains dropouts, cover them and swap
over without pulses on the power.

It is largely concerned with not running the batteries dry while they are
on trickle for month or years(what no testing?).

Unlike the consumer UPS, these systems are designed to do it over and
over again, but they can be fried if things go wrong.

No maintenance to save money, gennie comes in out of phase or runs out of
fuel after a short time and three of the reasons they can have major
problems.

 

[Trevor Wilson]

On 23/05/2015 12:58 PM, Sylvia Else wrote:

On 23/05/2015 7:26 AM, Trevor Wilson wrote:
On 22/05/2015 7:31 PM, Sylvia Else wrote:
On 22/05/2015 3:38 PM, news13 wrote:
On Fri, 22 May 2015 12:12:27 +1000, Sylvia Else wrote:


Either way, I'll have to look at that the economics of charging
these on
overnight off-peak power (generated by coal fired power stations) for
use during the evening peak when the much more expensive power would
otherwise be generated using less polluting natural gas, or even
hydro.

Maybe in ten years time they might be economical. Lead acid still has
the
rest beaten. The problem really is the cost to you of building suck a
system.

Though I don't know of a lead-acid battery that will survive a daily
deep cycle for ten years.

**They exist. Back when I worked for OTC, the battery rooms most of the
stations contained row upon row of huge, Pyrex™, lead/acid batteries.
They were designed to run an international telephone exchange several
hours, but preferably just long enough for the Diesel generators to
power up. In the Paddington exchange, the battery room had a 2 Tonne
fire door and half dozen 2 Metre high cylinders of CO2. In the event of
excessive H2, or a fire, the door would close automatically and the room
was flooded with CO2. Anyway, the batteries were not only designed to
last a very long time, but, in the event that a cell failed, it could be
relatively easily repaired. Of course, back then, OTC was awash with
cash and the hugely expensive batteries could be justified.

Sounds like the requirement was for batteries that that could left fully
charged almost all of the time, and only cycled infrequently, which is
rather different from the situation under discussion.

**Sort of. Since the batteries (and, indeed, the entire operation) were
mission-critical items (ALL of Australia's telecommunications with the
outside world), regular testing of all back-up systems was performed. At
least monthly, as I recall, the stations and exchanges were operated on
battery power only then on Diesel generators.

Make no mistake: The batteries used (they're probably still used today,
though most operations have been taken over by Telstra) are still
probably in place today. They were the very highest quality batteries
available. Price was never an issue for OTC. Way back in 1972 I saw my
first ink jet printer. It reputedly cost $2,500.00 was nonsensically
slow and print quality was laughable. My recollection is that the
platten, where the paper sits, was charged to a couple of thousand
Volts, thus attracting the ink to the paper. Saw my first computer (and
my first computer - took up the entire floor of the Paddington exchange)
drum drive too. 1.5 Metres long and a couple of hundred mm in diameter.
Hundreds of heads and fantastically fast access. The amount of money OTC
spent was mind-boggling, since anything left over went into government
coffers. They pretty much spent everything that was earned, lest the
government spend it on roads or some such nonsense.

I have no doubt that the batteries used could withstand all the cycling
required for decades of service.


--
Trevor Wilson
www.rageaudio.com.au

---
This email has been checked for viruses by Avast antivirus software.
http://www.avast.com

 

[Sylvia Else]

On 23/05/2015 9:35 PM, news13 wrote:

On Fri, 22 May 2015 19:31:51 +1000, Sylvia Else wrote:

On 22/05/2015 3:38 PM, news13 wrote:
On Fri, 22 May 2015 12:12:27 +1000, Sylvia Else wrote:


Either way, I'll have to look at that the economics of charging these
on overnight off-peak power (generated by coal fired power stations)
for use during the evening peak when the much more expensive power
would otherwise be generated using less polluting natural gas, or even
hydro.

Maybe in ten years time they might be economical. Lead acid still has
the rest beaten. The problem really is the cost to you of building suck
a system.

Though I don't know of a lead-acid battery that will survive a daily
deep cycle for ten years.

Err, never heard of "Deep cycle lead acid battery"?
Twenty years is viable and often achieved.


Like all batteries, each type has % depth, rates and cycle trade offs,
not to mention relative cost.

The rule of thumb seems to be 50% discharge gives the best economics.

Are you aware of a lead acid deep cycle battery whose manufacturer
states that it will last in excess of 3600 cycles at 50% discharge?

I don't know that they have a legal basis for objecting.

as an electrician said "I can't do it legally, but there is nothing to
Atop you doing it". I wanted a circuit running off the OP to keep a few
emergency batteries topped up.

I suspect they have some legal say on what is connected to their network.

It's just a battery that gets charged. People do it all the time. OK,
this one's a big battery, but where's the regulation that puts a limit
on the size of batteries being recharged?

We don't know that the electrician actually knew of a regulation.
Perhaps he heard it in the pub, or just didn't want to carry the
commercial risk of such an installation.

Sylvia.

 

[Colin Horsley]

On 23/05/2015 19:53, Trevor Wilson wrote:

**They exist. Back when I worked for OTC, the battery rooms most of the
stations contained row upon row of huge, Pyrex™, lead/acid batteries.
They were designed to run an international telephone exchange several
hours, but preferably just long enough for the Diesel generators to
power up. In the Paddington exchange, the battery room had a 2 Tonne
fire door and half dozen 2 Metre high cylinders of CO2.

Trevor,
Do you know where you can get the Pyrex™, lead/acid batteries?
I have a client who is looking for one or more. Size is not important.

Thanks

Colin

---
This email has been checked for viruses by Avast antivirus software.
http://www.avast.com

 

[Trevor Wilson]

On 24/05/2015 1:18 PM, Colin Horsley wrote:

On 23/05/2015 19:53, Trevor Wilson wrote:

**They exist. Back when I worked for OTC, the battery rooms most of the
stations contained row upon row of huge, Pyrex™, lead/acid batteries.
They were designed to run an international telephone exchange several
hours, but preferably just long enough for the Diesel generators to
power up. In the Paddington exchange, the battery room had a 2 Tonne
fire door and half dozen 2 Metre high cylinders of CO2.

Trevor,
Do you know where you can get the Pyrex™, lead/acid batteries?
I have a client who is looking for one or more. Size is not important.

**No idea. It has been almost 40 years since I set foot through an OTC
doorway. I can ask my local battery guy though. They seem to know a bot
about such things.


--
Trevor Wilson
www.rageaudio.com.au

---
This email has been checked for viruses by Avast antivirus software.
http://www.avast.com

 

[news13]

On Sun, 24 May 2015 01:27:17 +1000, Sylvia Else wrote:

On 23/05/2015 9:35 PM, news13 wrote:
On Fri, 22 May 2015 19:31:51 +1000, Sylvia Else wrote:

On 22/05/2015 3:38 PM, news13 wrote:
On Fri, 22 May 2015 12:12:27 +1000, Sylvia Else wrote:


Either way, I'll have to look at that the economics of charging
these on overnight off-peak power (generated by coal fired power
stations) for use during the evening peak when the much more
expensive power would otherwise be generated using less polluting
natural gas, or even hydro.

Maybe in ten years time they might be economical. Lead acid still has
the rest beaten. The problem really is the cost to you of building
suck a system.

Though I don't know of a lead-acid battery that will survive a daily
deep cycle for ten years.

Err, never heard of "Deep cycle lead acid battery"?
Twenty years is viable and often achieved.


Like all batteries, each type has % depth, rates and cycle trade offs,
not to mention relative cost.

The rule of thumb seems to be 50% discharge gives the best economics.

What thumbless idiot came up with that?
Let me guess, it is from wikipedia?
That statement only makes sense in a specific context; perhaps motorised
wheel chairs?

I've never heard it anywhere before.

Are you aware of a lead acid deep cycle battery whose manufacturer
states that it will last in excess of 3600 cycles at 50% discharge?

If I wanted long -life, I'd be planning on 10-20% discharge per day for a
DCLA. Only 3600 cycles should be easily achieved for wet under those
conditions.

I don't know that they have a legal basis for objecting.

as an electrician said "I can't do it legally, but there is nothing to
Atop you doing it". I wanted a circuit running off the OP to keep a few
emergency batteries topped up.

I suspect they have some legal say on what is connected to their
network.

It's just a battery that gets charged. People do it all the time. OK,
this one's a big battery, but where's the regulation that puts a limit
on the size of batteries being recharged?

Nope, not the battery, but the source.
If you are old plan; aka direct circuits, then it is apparently a problem.
If you're on time of day, just plug here in and go.

Caveat, they do what bills for sudden consumption changes.


I supposed the real test will be the take up by the whacky bacca brigade
to try and hide the huge electricity bill.

We don't know that the electrician actually knew of a regulation.
Perhaps he heard it in the pub, or just didn't want to carry the
commercial risk of such an installation.

All he had to do was check socket in garage and wire it in at meter box.

 

[Sylvia Else]

On 24/05/2015 7:51 PM, news13 wrote:

On Sun, 24 May 2015 01:27:17 +1000, Sylvia Else wrote:

On 23/05/2015 9:35 PM, news13 wrote:
On Fri, 22 May 2015 19:31:51 +1000, Sylvia Else wrote:

On 22/05/2015 3:38 PM, news13 wrote:
On Fri, 22 May 2015 12:12:27 +1000, Sylvia Else wrote:


Either way, I'll have to look at that the economics of charging
these on overnight off-peak power (generated by coal fired power
stations) for use during the evening peak when the much more
expensive power would otherwise be generated using less polluting
natural gas, or even hydro.

Maybe in ten years time they might be economical. Lead acid still has
the rest beaten. The problem really is the cost to you of building
suck a system.

Though I don't know of a lead-acid battery that will survive a daily
deep cycle for ten years.

Err, never heard of "Deep cycle lead acid battery"?
Twenty years is viable and often achieved.


Like all batteries, each type has % depth, rates and cycle trade offs,
not to mention relative cost.

The rule of thumb seems to be 50% discharge gives the best economics.

What thumbless idiot came up with that?
Let me guess, it is from wikipedia?
That statement only makes sense in a specific context; perhaps motorised
wheel chairs?

I've never heard it anywhere before.



Are you aware of a lead acid deep cycle battery whose manufacturer
states that it will last in excess of 3600 cycles at 50% discharge?

If I wanted long -life, I'd be planning on 10-20% discharge per day for a
DCLA. Only 3600 cycles should be easily achieved for wet under those
conditions.

But now you need more batteries, which pushes the price up.

Sylvia.

 

[Gordon Levi]

Sylvia Else <sylvia@not.at.this.address> wrote:

http://www.abc.net.au/news/2015-05-21/powerwall-solar-batteries-to-transform-electricity-industry/6488230

http://www.teslamotors.com/en_AU/powerwall

At $5500 (is that including GST?) for a 7kWh model, with a ten year
life, and allowing for interest, that comes in at about 28 cents per
kWh, and that's before the cost of the solar panels and the inverter
(not included with the battery), and installation, is included. It's
also based on the questionable (i.e. certainly false) assumption that
they can be recharged from solar everyday. The reality is that they
won't be, and the cost per kWh will be accordingly higher.

The limit of 2kW continuous and 3.3kW peak should also be noted. It
isn't clear how long one can draw 3.3kW for, but 2kW is less than is
required to run an ordinary domestic kettle. A typical household might
have trouble using the entire capacity, pushing up the effective cost
per kWh.

Hopefully, we are all set to "waste money" on minimising Anthropogenic
Global Warming! Households that are installing battery backed solar or
wind are doing their best to lower their own carbon footprint.

If you doubt that AGW is a problem then any waste of money on
batteries is insignificant compared to the government's "waste of
money" Direct Action Plan and Renewable Energy Targets.

The good thing about these is that they may finally force a change to
the way electricity is charged for, with much greater emphasis placed on
the cost of making it available versus the cost of supplying it when
it's required. People who treat the grid as a backup will then pay
something closer to the true cost of using it that way.

Once again, you assume that the "true cost" does not include the cost
of AGW. If the aim is to minimise carbon emissions then it is
inevitable that we will pay more for electricity. The aim should be to
regard carbon emissions as a major cost and to tailor the supply to
maximise the use of renewables.

Either way, I'll have to look at that the economics of charging these on
overnight off-peak power (generated by coal fired power stations)

That must change. Base _load_ is often confused with the cheapest
_supply_. Coal and gas should only be used if renewables cannot meet
the current load.

for
use during the evening peak when the much more expensive power would
otherwise be generated using less polluting natural gas, or even hydro.

 

[news13]

On Mon, 25 May 2015 08:55:44 +1000, Adrian Jansen wrote:

Stanford uni has a very long history of producing papers on all sorts of
wonderful stuff which never make it to commercial production.

The fact that people have been working on Al batteries for about 20
years already with no success tells me it might be difficult.

My take on the Tesla announcement is that Elon Musk needs an outlet for
the batteries he is using for electric cars, now that sales for those
are way below the original forecasts.

Nope, just the logistics of battery production, plus these "new
entrepreneur's" way of doing business; wham, bam and thank you, or here
today and gone tomorrow.

If he can drive the production cost down by producing more, then he'll
carve a niche for his product. He is just trying to generate sales to the
gullible, just like just about every other product out there.

Certainly a 7KWh power pack is nowhere near enough for anything other
than emergency supply for a domestic house. Work out the capacity you
need for say 3-4 days without useful sunshine. Here in sunny Queensland
we have that regularly 2-3 times a year. No possible way you can go
off-grid.

And yes, I have a solar array, and make a good profit selling the excess
power back to the grid, but there is no way I could justify batteries
and go off grid.

Off grid no, but covering peak cost times is a different matter.

 

[news13]

On Sun, 24 May 2015 20:19:58 +1000, Sylvia Else wrote:

On 24/05/2015 7:51 PM, news13 wrote:

Are you aware of a lead acid deep cycle battery whose manufacturer
states that it will last in excess of 3600 cycles at 50% discharge?

If I wanted long -life, I'd be planning on 10-20% discharge per day for
a DCLA. Only 3600 cycles should be easily achieved for wet under those
conditions.

But now you need more batteries, which pushes the price up.

Rule one, if you see price as the limitation, then you'd better study
study investments 101 again and redo your figures.