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bitrex
Guest

Wed Jan 09, 2019 8:45 pm   



On 01/09/2019 06:46 AM, Clive Arthur wrote:
Quote:
On 09/01/2019 00:45, bitrex wrote:
On 01/08/2019 07:02 PM, jurb6006_at_gmail.com wrote:
"You can pick up 48V 45 ampere/hour surplus individual pack modules off
eBay relatively cheap, tho (it takes about eight of these to make a full
pack for the car) "

We are still in the figuring out the need stage. Part of it can be
changed, like a DC fridge is alot more expensive and usually too
small, but a bigger invertor and a bit more battery ? Might be worth it.

Those individual pack modules, from what ? Tesla or something else ?


a salvage Chevrolet Volt, a la:

https://d2t6ms4cjod3h9.cloudfront.net/wp-content/uploads/2014/12/CRASH2a.jpg


"It will buff out"

https://www.youtube.com/watch?v=Z4fBbhyzE9A

Cheers


Looking at the Volt wreck I would say....Ah! You're low on windshield
wiper fluid there's your problem


Guest

Wed Jan 09, 2019 9:45 pm   



On Wednesday, January 9, 2019 at 4:31:43 AM UTC-5, Martin Brown wrote:
Quote:
On 09/01/2019 07:20, Jeff Liebermann wrote:
On Tue, 8 Jan 2019 16:30:10 -0800 (PST), jurb6006_at_gmail.com wrote:

"Forget that idea. Assuming you mean the Tesla PowerWall 1, 2, or 3, these were not designed to power anything."

I had to look that up. No, what he was considering is using actual Tesla car batteries.

Where is he going to put the battery? They were designed to fit in a
car, not a house.
https://www.google.com/search?q=tesla+battery&tbm=isch

Are the car batteries and Powerwall internals the same chemistry 18650
AA cells? ISTR Powerwalls are allegedly happy down to around -10C which
means they would be OK in an outside building in the UK. TBH I would not
want one inside my house. I know just how well lithium metal burns.


I don't think the power wall would be "happy" down to -10°C. In the car they restrict charge/discharge rate when they get cold. Even 45°F (around 10°C) they start to be limited in rate and the capacity also drops off. Of course the power wall won't need anything like the rates you see in a car battery.

If you don't like LiIon you might want to dump your phone and nearly every other battery appliance you own.


Quote:
Would it hurt to charge too slowly ?

I'm not sure, but I think it's ok. However, you won't get more life
out of the battery by trickle charging it.
"Want lithium-ion batteries to last? Slow charging may not be the
answer"
https://www.pcworld.com/article/2683012/want-lithiumion-batteries-to-last-slow-charging-may-not-be-the-answer.html

What really hurts is to over charge them or over discharge them. The
latter potentially destroying the battery and making it dangerous. The
cutouts in laptop battery packs defend against such abuses.


You simply don't want to design your own charger and none of that becomes and issue. But it is worse than that. You don't want to 100% charge them or discharge to 0% and let them sit. When not in use they should be kept between 20% and 80% for maximum life. 10/90 is not so bad, but 0/100 is definitely a problem.


Quote:
The only reason to even think about designing a charger it because
it may be that the normal charger cannot be run on too low a current,
or voltage depending... Perhaps the usual charger with a bypass
to get it to a certain point where it will rune ? Something like that.

What's a "normal" charger? Most EV chargers try to charge at very
high charge rates as limited by what the AC power line can provide.

If you are trying to pump the maximum in as quickly as possible then
yes. I don't know about you but my instinct is that if you are getting
the pack seriously hot when charging then lifetime is probably reduced.


No AC charger for Tesla batteries comes even close to maxing out the charge rate. Fastest AC charger is 80 amps or about 20 kW. Fast DC chargers are up to 120 kW.


Quote:
This is new to me, but I don't scare easily.

You scare me. I'm worried that you might actually build what you're
suggesting which would then either explode or catch fire.

The OP would do well to watch some of the videos of what happens to the
really tiny lithium batteries in vaping units when the charging regime
is not correctly followed. ISTR Royal Institution Christmas lectures did
it to a decent sized battery pack a couple of years back (on the roof).

https://youtu.be/03AYPddTv8w


Better to watch some videos of what others are doing with Tesla batteries.


Quote:
My main concern is the life of the batteries, after the power
demands are met.

My main concern is the life of the builder and owner.

Darwin Award would seem to be imminent.

He would be much better off using deep discharge lead acid since they
are much less likely to catch fire when abused (as seems inevitable).


No reason to abuse them. With nearly half a million cars in the world an no reports of batteries catching fire from charging.


Quote:
Permit me to offer a different way to look at this. If you design a
home power system, the way to make the battery last as long as
possible is to not use the battery. Yep, just charge it up, leave it
up, and don't pull any power from it. It's the charge and discharge
cycles that tend to kill batteries. Reduce their frequency and depth
of discharge, and your battery will last longer.

I'm less certain of that. If you don't cycle it every now and then they
seem to lose capacity. My laptop batteries tend to die after about 5
years because they spend too much time on mains power.


The problem there is sitting at 100% charge all the time. Most laptops will warn you of that. Unfortunately they aren't smart enough to not charge them to 100% or to give you a way of controlling this. They only let you know it is a problem without giving you a solution.


Quote:
There's a reason that everyone isn't rushing out to replace their
lead-acid and nickel-iron solar battery storage systems with LiIon.
Read about the relative merits and disadvantages of the common battery
chemistry choices:
https://www.homepower.com/articles/solar-electricity/equipment-products/battery-chemistry?v=print

Lead acid and nickel-iron will take a lot of abuse and still work.


And weigh a ton or three. Remember, while this is not going to move the vehicle, it is going in one.


Quote:
UK MOD made a horrendous mess by applying an old power top up SOP to
newly introduced NiCads back in the 1980's destroying a great many big
expensive wet cell batteries in the process. Being cycled between 80%
charge and full many times left them unable to provide full capacity.
NiFe by comparison would put up with almost any amount of abuse.


Don't know what MOD or SOP are. Since when are NiCads wet cells?


Quote:
Can I run away while I'm still sane?

+1

--
Regards,
Martin Brown


Rick C.

-- Get 6 months of free supercharging
-- Tesla referral code - https://ts.la/richard11209


Guest

Wed Jan 09, 2019 9:45 pm   



On Wednesday, January 9, 2019 at 4:08:09 AM UTC-5, Martin Brown wrote:
Quote:
On 09/01/2019 07:45, Jeff Liebermann wrote:
On Tue, 8 Jan 2019 08:50:22 +0000, Martin Brown
'''newspam'''@nezumi.demon.co.uk> wrote:

On 08/01/2019 06:32, Jeff Liebermann wrote:
On Mon, 7 Jan 2019 12:28:49 -0800 (PST), jurb6006_at_gmail.com wrote:

Going off the grid (not me not now but...) we are looking at Tesla batteries for energy storage.

Forget that idea. Assuming you mean the Tesla PowerWall 1, 2, or 3,
these were not designed to power anything. They were designed to
reduce your peak power usage (time of use load shifting) thus saving
you money on your electric utility bill.

You have me interested now. I thought in the USA peak power load was
typically in mid afternoon when aircon was at full stretch and by
implication solar panels also at peak output.

http://www.caiso.com/TodaysOutlook/Pages/default.aspx
Note that solar and wind system, as well as off-grid systems, that
provide their own power, don't appear on the graph. Only those system
that draw power from the grid appear. As such, we have peaks at about
7 AM and 5:30 PM. The trough at noon is when solar power is at
maximum, which reduces the maximum demand.

Interesting quite how different UK and USA demand profiles are at this
time of year. UK comes up to a level plateau at 0800 until 1600 for the
working day and then peaks in the early evening around 1800 as people
return home to start cooking and using heating and lighting.

https://gridwatch.templar.co.uk/


In the US we have a morning peak and a late afternoon peak. Both peaks are due to the overlap of business and residential usage. In the summer months the morning peak becomes insignificant to the afternoon peak because of the AC. Of course this varies somewhat with region. It is a large and varied country.


Quote:
It is actually very mild for winter at the moment around 8-10C so that
there is comparatively little heating demand. It spikes more when there
is a cold snap to -10C (possibly by enough to bring the grid down).
Successive governments have prevaricated for so long over new build
nuclear that things are very borderline now for peak load vs capacity.
They had to pay some heavy industrial users to drop off grid last winter
(people like the electrolytic metals refiners - ultimate sink load).


You mean during peak times, right? It would make no sense to have them shut down. Just let them work other than at peak. Most factories like that work multiple shifts anyway.


Quote:
Surely the purpose of a
Tesla power wall *is* to store any excess solar power to use later in
the evening when the sun has gone down (rather than dumping it into the
hot water immersion heater - as is common in the UK).

That's exactly what it's for. You charge up your PowerWall late at
night, when electricity is cheap, and discharge it during the early
morning and evening, when electricity is more expensive. No solar
involved as everything is powered by the grid.

In the UK such battery packs are being sold in combination with solar
arrays. Although we do have some cheap overnight electricity tariffs
they have largely fallen out of favour - daytime is a rip-off. They are
mostly a hangover of the "nuclear electricity to cheap to meter" era.


Not sure what that means. What does nuclear have to do with peak rates?


Quote:
Government is presently rolling out dumb-as-hell cryptographically
insecure "smart" meters to aid roll out of dynamic pricing. Snag is they
don't work at all where I live - no mobile coverage inside the house. We
can expect interesting times ahead when hackers try to damage UK power
network infrastructure by switching domestic loads on and off the net in
large chunks. My meter is prehistoric with counter rotating dials
numbered 0-9 it confuses the hell out of younger meter readers.


That's what I had until recently when they installed a digital meter. Oh well.


Quote:
There are second generation meters now but they continue to install the
dud ones because they have them and also have a crazy deadline to miss.

https://www.moneysavingexpert.com/news/2018/11/smart-meters-tech-problem-delay/

You couldn't make it up!

A quirk of the
feed-in-tariff is that you get paid a premium rate for half of what you
generate no matter what you do with it (insane).

That's a different animal. That's using solar or wind power to
generate electricity, which is then sent to the grid for "storage" or
to be consumed by someone else. In theory, you're saving the local
utility the cost of gas and oil needed to generate that electricity.
Of course that assumes that there's someone available to consume the
electricity you generate, or that the utility or grid have a way of
storing it. It's conceivable that on a really sunny day, residential
solar power could generate more power than users could consume.

But if you are not at home during the day to use it then storing it in a
battery means you get paid for (not) "delivering it to the grid" and
then get to use it later when you come home. This is part of the reason
why solar hot water is a non-starter in the UK. The feed in tariff makes
it more cost effective to generate PV electricity and dump it into your
hot water tank immersion heater since you get paid to do that!


I don't understand what you mean by "paid for not delivering it to the grid"???


Quote:
ISTR they come in 12kWhr blocks and are notable for being able to
withstand being installed outside in the cold (UK never below -15C).

That's the industrial Tesla PowerPack. They come in different shapes
and sizes:
https://www.tesla.com/powerpack
https://electrek.co/2018/07/16/tesla-powerwalls-new-virtual-power-plant-australia/

Locally, Tesla and PG&E are working at installing a PowerPack at the
Moss Landing power plant:
https://electrek.co/2018/06/29/tesla-pge-giant-1-gwh-powerpack-battery-system/
The justification is that it is cheaper to install these giant battery
packs to deal with the demand peaks, than it is to increase generation
capacity to handle the demand peaks.

We have a lot of gas turbine systems (and pumped storage) for demand
peaks. It is a problem that most generation occurs in the north whereas
the bulk of the consumption is in the south around London and SE.

What is the peak discharge rate that they can cope with in practice?

Which one? The home PowerWall or the utility PowerPack system? I
once found and posted in this group the web site that monitors the
PowerPack, which provided numbers for what was going in and out.
However, I can't find it again. I'll try again tomorrow or day after.

It was the 12kW (or above) system that I was interested in. That would
provide enough capacity to buffer a respectable amount of energy. I am
thinking here of solar 4kW array with battery storage for my home.


12 kW is four times my typical peak usage. Much of the day when the heat or AC is not running my consumption is around 1 kW... peak.


Quote:
My question pretty much amounts to can it support a 3kW discharge rate
or would I always have to take some electricity for peak loads even if
the battery was fully charged.


I haven't looked up the spec, but it would be a pretty crappy battery if it couldn't deliver 3 kW. That's about 30 amps at 120 VAC or 15 amps at 240 VAC.

Rick C.

-+ Get 6 months of free supercharging
-+ Tesla referral code - https://ts.la/richard11209

Lasse Langwadt Christense
Guest

Wed Jan 09, 2019 9:45 pm   



onsdag den 9. januar 2019 kl. 21.07.56 UTC+1 skrev gnuarm.del...@gmail.com:
Quote:
On Wednesday, January 9, 2019 at 4:31:43 AM UTC-5, Martin Brown wrote:
On 09/01/2019 07:20, Jeff Liebermann wrote:
On Tue, 8 Jan 2019 16:30:10 -0800 (PST), jurb6006_at_gmail.com wrote:

"Forget that idea. Assuming you mean the Tesla PowerWall 1, 2, or 3, these were not designed to power anything."

I had to look that up. No, what he was considering is using actual Tesla car batteries.

Where is he going to put the battery? They were designed to fit in a
car, not a house.
https://www.google.com/search?q=tesla+battery&tbm=isch

Are the car batteries and Powerwall internals the same chemistry 18650
AA cells? ISTR Powerwalls are allegedly happy down to around -10C which
means they would be OK in an outside building in the UK. TBH I would not
want one inside my house. I know just how well lithium metal burns.

I don't think the power wall would be "happy" down to -10°C. In the car they restrict charge/discharge rate when they get cold. Even 45°F (around 10°C) they start to be limited in rate and the capacity also drops off. Of course the power wall won't need anything like the rates you see in a car battery.

If you don't like LiIon you might want to dump your phone and nearly every other battery appliance you own.


Would it hurt to charge too slowly ?

I'm not sure, but I think it's ok. However, you won't get more life
out of the battery by trickle charging it.
"Want lithium-ion batteries to last? Slow charging may not be the
answer"
https://www.pcworld.com/article/2683012/want-lithiumion-batteries-to-last-slow-charging-may-not-be-the-answer.html

What really hurts is to over charge them or over discharge them. The
latter potentially destroying the battery and making it dangerous. The
cutouts in laptop battery packs defend against such abuses.

You simply don't want to design your own charger and none of that becomes and issue. But it is worse than that. You don't want to 100% charge them or discharge to 0% and let them sit. When not in use they should be kept between 20% and 80% for maximum life. 10/90 is not so bad, but 0/100 is definitely a problem.


The only reason to even think about designing a charger it because
it may be that the normal charger cannot be run on too low a current,
or voltage depending... Perhaps the usual charger with a bypass
to get it to a certain point where it will rune ? Something like that.

What's a "normal" charger? Most EV chargers try to charge at very
high charge rates as limited by what the AC power line can provide.

If you are trying to pump the maximum in as quickly as possible then
yes. I don't know about you but my instinct is that if you are getting
the pack seriously hot when charging then lifetime is probably reduced.

No AC charger for Tesla batteries comes even close to maxing out the charge rate. Fastest AC charger is 80 amps or about 20 kW. Fast DC chargers are up to 120 kW.


This is new to me, but I don't scare easily.

You scare me. I'm worried that you might actually build what you're
suggesting which would then either explode or catch fire.

The OP would do well to watch some of the videos of what happens to the
really tiny lithium batteries in vaping units when the charging regime
is not correctly followed. ISTR Royal Institution Christmas lectures did
it to a decent sized battery pack a couple of years back (on the roof).

https://youtu.be/03AYPddTv8w

Better to watch some videos of what others are doing with Tesla batteries..


My main concern is the life of the batteries, after the power
demands are met.

My main concern is the life of the builder and owner.

Darwin Award would seem to be imminent.

He would be much better off using deep discharge lead acid since they
are much less likely to catch fire when abused (as seems inevitable).

No reason to abuse them. With nearly half a million cars in the world an no reports of batteries catching fire from charging.


Permit me to offer a different way to look at this. If you design a
home power system, the way to make the battery last as long as
possible is to not use the battery. Yep, just charge it up, leave it
up, and don't pull any power from it. It's the charge and discharge
cycles that tend to kill batteries. Reduce their frequency and depth
of discharge, and your battery will last longer.

I'm less certain of that. If you don't cycle it every now and then they
seem to lose capacity. My laptop batteries tend to die after about 5
years because they spend too much time on mains power.

The problem there is sitting at 100% charge all the time. Most laptops will warn you of that. Unfortunately they aren't smart enough to not charge them to 100% or to give you a way of controlling this. They only let you know it is a problem without giving you a solution.


lenovo does

https://filestore.community.support.microsoft.com/api/images/8cf0499c-6227-4155-9d36-79fa99015866?upload=true


Guest

Thu Jan 10, 2019 12:45 am   



On Wednesday, January 9, 2019 at 3:26:46 PM UTC-5, Lasse Langwadt Christensen wrote:
Quote:
onsdag den 9. januar 2019 kl. 21.07.56 UTC+1 skrev gnuarm.del...@gmail.com:
On Wednesday, January 9, 2019 at 4:31:43 AM UTC-5, Martin Brown wrote:

I'm less certain of that. If you don't cycle it every now and then they
seem to lose capacity. My laptop batteries tend to die after about 5
years because they spend too much time on mains power.

The problem there is sitting at 100% charge all the time. Most laptops will warn you of that. Unfortunately they aren't smart enough to not charge them to 100% or to give you a way of controlling this. They only let you know it is a problem without giving you a solution.


lenovo does

https://filestore.community.support.microsoft.com/api/images/8cf0499c-6227-4155-9d36-79fa99015866?upload=true


Wow! I'm amazed. Lenovo actually did something right! My Lenovo wouldn't even let me run it on a charger if it wasn't an exact match to the expensive one that came with the laptop. It was without a doubt the worst computer I've ever had including the single board Technico 9900 I still have in the basement somewhere, but it doesn't have a USB port.

Rick C.

+- Get 6 months of free supercharging
+- Tesla referral code - https://ts.la/richard11209


Guest

Thu Jan 10, 2019 8:45 am   



On Wed, 9 Jan 2019 09:07:56 +0000, Martin Brown
<'''newspam'''@nezumi.demon.co.uk> wrote:

Quote:
Locally, Tesla and PG&E are working at installing a PowerPack at the
Moss Landing power plant:
https://electrek.co/2018/06/29/tesla-pge-giant-1-gwh-powerpack-battery-system/
The justification is that it is cheaper to install these giant battery
packs to deal with the demand peaks, than it is to increase generation
capacity to handle the demand peaks.


Simple gas turbines are cheap, but the fuel cost may be significant,
if you have to run them at more than a few hundred hours each year.

The great advantage of battery packs is that it can immediately react
to loss of production capacity of rapid increase in demand. Thus 15-30
minute storage capacity is enough so that you can get gas turbines
started. This also reduces the need for spinning reserve in
continuously running power plants.

Quote:
We have a lot of gas turbine systems (and pumped storage) for demand
peaks. It is a problem that most generation occurs in the north whereas
the bulk of the consumption is in the south around London and SE.


While pumping storage is possible only in Scotland, but gas turbines
could be installed everywhere as long as there are nearby pipelines.
The North Sea oil and gas fields feeds these pipelines.


Guest

Thu Jan 10, 2019 9:45 am   



On Wednesday, 9 January 2019 19:54:01 UTC, gnuarm.del...@gmail.com wrote:
Quote:
On Wednesday, January 9, 2019 at 4:08:09 AM UTC-5, Martin Brown wrote:
On 09/01/2019 07:45, Jeff Liebermann wrote:
On Tue, 8 Jan 2019 08:50:22 +0000, Martin Brown


Quote:
It is actually very mild for winter at the moment around 8-10C so that
there is comparatively little heating demand. It spikes more when there
is a cold snap to -10C (possibly by enough to bring the grid down).
Successive governments have prevaricated for so long over new build
nuclear that things are very borderline now for peak load vs capacity.
They had to pay some heavy industrial users to drop off grid last winter
(people like the electrolytic metals refiners - ultimate sink load).

You mean during peak times, right? It would make no sense to have them shut down. Just let them work other than at peak. Most factories like that work multiple shifts anyway.


so you don't know how that setup works


Quote:
In the UK such battery packs are being sold in combination with solar
arrays. Although we do have some cheap overnight electricity tariffs
they have largely fallen out of favour - daytime is a rip-off. They are
mostly a hangover of the "nuclear electricity to cheap to meter" era.

Not sure what that means. What does nuclear have to do with peak rates?


or that


Quote:
storing it. It's conceivable that on a really sunny day, residential
solar power could generate more power than users could consume.


rather unlikely

Quote:
But if you are not at home during the day to use it then storing it in a
battery means you get paid for (not) "delivering it to the grid" and
then get to use it later when you come home. This is part of the reason
why solar hot water is a non-starter in the UK. The feed in tariff makes
it more cost effective to generate PV electricity and dump it into your
hot water tank immersion heater since you get paid to do that!

I don't understand what you mean by "paid for not delivering it to the grid"???


why?

Quote:
ISTR they come in 12kWhr blocks and are notable for being able to
withstand being installed outside in the cold (UK never below -15C).

That's the industrial Tesla PowerPack. They come in different shapes
and sizes:
https://www.tesla.com/powerpack
https://electrek.co/2018/07/16/tesla-powerwalls-new-virtual-power-plant-australia/

Locally, Tesla and PG&E are working at installing a PowerPack at the
Moss Landing power plant:
https://electrek.co/2018/06/29/tesla-pge-giant-1-gwh-powerpack-battery-system/
The justification is that it is cheaper to install these giant battery
packs to deal with the demand peaks, than it is to increase generation
capacity to handle the demand peaks.

We have a lot of gas turbine systems (and pumped storage) for demand
peaks. It is a problem that most generation occurs in the north whereas
the bulk of the consumption is in the south around London and SE.

What is the peak discharge rate that they can cope with in practice?

Which one? The home PowerWall or the utility PowerPack system? I
once found and posted in this group the web site that monitors the
PowerPack, which provided numbers for what was going in and out.
However, I can't find it again. I'll try again tomorrow or day after.

It was the 12kW (or above) system that I was interested in. That would
provide enough capacity to buffer a respectable amount of energy. I am
thinking here of solar 4kW array with battery storage for my home.

12 kW is four times my typical peak usage. Much of the day when the heat or AC is not running my consumption is around 1 kW... peak.


Peak consumption of 3kW is possible but most unusual in the developed world.


Quote:
My question pretty much amounts to can it support a 3kW discharge rate
or would I always have to take some electricity for peak loads even if
the battery was fully charged.

I haven't looked up the spec, but it would be a pretty crappy battery if it couldn't deliver 3 kW. That's about 30 amps at 120 VAC or 15 amps at 240 VAC.


No it isn't.


NT


Guest

Thu Jan 10, 2019 9:45 am   



On Wednesday, 9 January 2019 20:07:56 UTC, gnuarm.del...@gmail.com wrote:
Quote:
On Wednesday, January 9, 2019 at 4:31:43 AM UTC-5, Martin Brown wrote:

UK MOD made a horrendous mess by applying an old power top up SOP to
newly introduced NiCads back in the 1980's destroying a great many big
expensive wet cell batteries in the process. Being cycled between 80%
charge and full many times left them unable to provide full capacity.
NiFe by comparison would put up with almost any amount of abuse.

Don't know what MOD or SOP are. Since when are NiCads wet cells?


ministry of defence. standard operating practice. 1899.

Martin Brown
Guest

Thu Jan 10, 2019 10:45 am   



On 09/01/2019 19:53, gnuarm.deletethisbit_at_gmail.com wrote:
Quote:
On Wednesday, January 9, 2019 at 4:08:09 AM UTC-5, Martin Brown
wrote:
On 09/01/2019 07:45, Jeff Liebermann wrote:
On Tue, 8 Jan 2019 08:50:22 +0000, Martin Brown
'''newspam'''@nezumi.demon.co.uk> wrote:

On 08/01/2019 06:32, Jeff Liebermann wrote:
On Mon, 7 Jan 2019 12:28:49 -0800 (PST), jurb6006_at_gmail.com
wrote:

Going off the grid (not me not now but...) we are looking
at Tesla batteries for energy storage.

Forget that idea. Assuming you mean the Tesla PowerWall 1,
2, or 3, these were not designed to power anything. They
were designed to reduce your peak power usage (time of use
load shifting) thus saving you money on your electric utility
bill.

You have me interested now. I thought in the USA peak power
load was typically in mid afternoon when aircon was at full
stretch and by implication solar panels also at peak output.

http://www.caiso.com/TodaysOutlook/Pages/default.aspx> Note that
solar and wind system, as well as off-grid systems, that provide
their own power, don't appear on the graph. Only those system
that draw power from the grid appear. As such, we have peaks at
about 7 AM and 5:30 PM. The trough at noon is when solar power
is at maximum, which reduces the maximum demand.

Interesting quite how different UK and USA demand profiles are at
this time of year. UK comes up to a level plateau at 0800 until
1600 for the working day and then peaks in the early evening around
1800 as people return home to start cooking and using heating and
lighting.

https://gridwatch.templar.co.uk/

In the US we have a morning peak and a late afternoon peak. Both
peaks are due to the overlap of business and residential usage. In
the summer months the morning peak becomes insignificant to the
afternoon peak because of the AC. Of course this varies somewhat
with region. It is a large and varied country.


I take this to imply that cooked breakfasts are more common in the USA then.

Quote:
It is actually very mild for winter at the moment around 8-10C so
that there is comparatively little heating demand. It spikes more
when there is a cold snap to -10C (possibly by enough to bring the
grid down). Successive governments have prevaricated for so long
over new build nuclear that things are very borderline now for peak
load vs capacity. They had to pay some heavy industrial users to
drop off grid last winter (people like the electrolytic metals
refiners - ultimate sink load).

You mean during peak times, right? It would make no sense to have
them shut down. Just let them work other than at peak. Most
factories like that work multiple shifts anyway.


No I mean that last year they had to pay heavy industrial users to drop
off the grid because gas availability and electricity generating
capacity were maxed out during "the beast from the East" weather - an
extended cold snap (which may happen again this year).

https://www.ft.com/content/30fa54b2-5e16-11e4-bc04-00144feabdc0

It has got worse since that 2014 article.

Quote:
Surely the purpose of a Tesla power wall *is* to store any
excess solar power to use later in the evening when the sun has
gone down (rather than dumping it into the hot water immersion
heater - as is common in the UK).

That's exactly what it's for. You charge up your PowerWall late
at night, when electricity is cheap, and discharge it during the
early morning and evening, when electricity is more expensive.
No solar involved as everything is powered by the grid.

In the UK such battery packs are being sold in combination with
solar arrays. Although we do have some cheap overnight electricity
tariffs they have largely fallen out of favour - daytime is a
rip-off. They are mostly a hangover of the "nuclear electricity to
cheap to meter" era.

Not sure what that means. What does nuclear have to do with peak
rates?


Nuclear needs a higher base load. In the 1960's when nuclear was all the
rage building the power plants it was said by the British government
spokesman that we would have "electricity too cheap to meter".

https://en.wikipedia.org/wiki/Too_cheap_to_meter

(a phrase apparently coined by Lewis Strauss of USAEC)

Economy 7 was a tariff intended to encourage people to use electric
storage heaters overnight on cheap electricity. They were utter crap.

Quote:
A quirk of the feed-in-tariff is that you get paid a premium
rate for half of what you generate no matter what you do with
it (insane).

That's a different animal. That's using solar or wind power to
generate electricity, which is then sent to the grid for
"storage" or to be consumed by someone else. In theory, you're
saving the local utility the cost of gas and oil needed to
generate that electricity. Of course that assumes that there's
someone available to consume the electricity you generate, or
that the utility or grid have a way of storing it. It's
conceivable that on a really sunny day, residential solar power
could generate more power than users could consume.

But if you are not at home during the day to use it then storing it
in a battery means you get paid for (not) "delivering it to the
grid" and then get to use it later when you come home. This is part
of the reason why solar hot water is a non-starter in the UK. The
feed in tariff makes it more cost effective to generate PV
electricity and dump it into your hot water tank immersion heater
since you get paid to do that!

I don't understand what you mean by "paid for not delivering it to
the grid"???


You get paid for exactly half of what your PV array produces
*irrespective* of what you actually do with it. Most people turn it into
copious hot water but if you are cunning you can store it in a battery
and use it later in the evening. Hence battery with PV combo sales are
more popular in the UK to avoid using grid electricity.

I think in the US they may well measure the amount of energy you deliver
to the grid and "bank" it or something.

Quote:
Which one? The home PowerWall or the utility PowerPack system?
I once found and posted in this group the web site that monitors
the PowerPack, which provided numbers for what was going in and
out. However, I can't find it again. I'll try again tomorrow or
day after.

It was the 12kW (or above) system that I was interested in. That
would provide enough capacity to buffer a respectable amount of
energy. I am thinking here of solar 4kW array with battery storage
for my home.

12 kW is four times my typical peak usage. Much of the day when the
heat or AC is not running my consumption is around 1 kW... peak.


I meant 12kWh battery capacity.

Quote:
My question pretty much amounts to can it support a 3kW discharge
rate or would I always have to take some electricity for peak loads
even if the battery was fully charged.

I haven't looked up the spec, but it would be a pretty crappy battery
if it couldn't deliver 3 kW. That's about 30 amps at 120 VAC or 15
amps at 240 VAC.


Regular discharge at C/4 is quite stressful for a battery. 3kW is a
typical peak load in the UK for kettles and electric fan heaters.

--
Regards,
Martin Brown

Martin Brown
Guest

Thu Jan 10, 2019 11:45 am   



On 10/01/2019 07:03, upsidedown_at_downunder.com wrote:
Quote:
On Wed, 9 Jan 2019 09:07:56 +0000, Martin Brown
'''newspam'''@nezumi.demon.co.uk> wrote:

Locally, Tesla and PG&E are working at installing a PowerPack at the
Moss Landing power plant:
https://electrek.co/2018/06/29/tesla-pge-giant-1-gwh-powerpack-battery-system/
The justification is that it is cheaper to install these giant battery
packs to deal with the demand peaks, than it is to increase generation
capacity to handle the demand peaks.

Simple gas turbines are cheap, but the fuel cost may be significant,
if you have to run them at more than a few hundred hours each year.


I thought fracking had made gas prices plummet. UK has certainly had a
"dash for gas" in the past couple of decades incredibly short termism.

https://en.wikipedia.org/wiki/Dash_for_Gas
Quote:

The great advantage of battery packs is that it can immediately react
to loss of production capacity of rapid increase in demand. Thus 15-30
minute storage capacity is enough so that you can get gas turbines
started. This also reduces the need for spinning reserve in
continuously running power plants.


I can see that adding a certain amount of this to the mix might save a
bit on spinning reserve wear and tear.
Quote:

We have a lot of gas turbine systems (and pumped storage) for demand
peaks. It is a problem that most generation occurs in the north whereas
the bulk of the consumption is in the south around London and SE.

While pumping storage is possible only in Scotland, but gas turbines
could be installed everywhere as long as there are nearby pipelines.
The North Sea oil and gas fields feeds these pipelines.


The UK's biggest pumped storage is actually in Wales. I knew one of the
engineers who worked on it. Dinorwig is a 1.7GW plant.

https://www.theengineer.co.uk/issues/march-2015-digi-issue/pumped-storage-a-new-project-for-wales/

It is thirty years old and only now are they thinking about adding more
despite having a far more volatile mix of renewables on the grid.

--
Regards,
Martin Brown


Guest

Thu Jan 10, 2019 2:45 pm   



On Thursday, January 10, 2019 at 6:03:45 PM UTC+11, upsid...@downunder.com wrote:
Quote:
On Wed, 9 Jan 2019 09:07:56 +0000, Martin Brown
'''newspam'''@nezumi.demon.co.uk> wrote:

Locally, Tesla and PG&E are working at installing a PowerPack at the
Moss Landing power plant:
https://electrek.co/2018/06/29/tesla-pge-giant-1-gwh-powerpack-battery-system/
The justification is that it is cheaper to install these giant battery
packs to deal with the demand peaks, than it is to increase generation
capacity to handle the demand peaks.

Simple gas turbines are cheap, but the fuel cost may be significant,
if you have to run them at more than a few hundred hours each year.

The great advantage of battery packs is that it can immediately react
to loss of production capacity of rapid increase in demand. Thus 15-30
minute storage capacity is enough so that you can get gas turbines
started. This also reduces the need for spinning reserve in
continuously running power plants.

We have a lot of gas turbine systems (and pumped storage) for demand
peaks. It is a problem that most generation occurs in the north whereas
the bulk of the consumption is in the south around London and SE.

While pumping storage is possible only in Scotland,


And Wales.

https://en.wikipedia.org/wiki/Dinorwig_Power_Station

> but gas turbines could be installed everywhere as long as there are nearby pipelines. The North Sea oil and gas fields feeds these pipelines.

And the UK is full of domestic gas-fired central-heating and hot-water system.

The country is covered by a natural gas distribution network.

You don't actually need mountains for pumped water storage, and pumped compressed air storage is even easier to accommodate.

--
Bill Sloman, Sydney


Guest

Fri Jan 11, 2019 1:45 am   



On Thursday, January 10, 2019 at 3:41:27 AM UTC-5, tabb...@gmail.com wrote:
Quote:
On Wednesday, 9 January 2019 19:54:01 UTC, gnuarm.del...@gmail.com wrote:
On Wednesday, January 9, 2019 at 4:08:09 AM UTC-5, Martin Brown wrote:
On 09/01/2019 07:45, Jeff Liebermann wrote:
On Tue, 8 Jan 2019 08:50:22 +0000, Martin Brown


It is actually very mild for winter at the moment around 8-10C so that
there is comparatively little heating demand. It spikes more when there
is a cold snap to -10C (possibly by enough to bring the grid down).
Successive governments have prevaricated for so long over new build
nuclear that things are very borderline now for peak load vs capacity.
They had to pay some heavy industrial users to drop off grid last winter
(people like the electrolytic metals refiners - ultimate sink load).

You mean during peak times, right? It would make no sense to have them shut down. Just let them work other than at peak. Most factories like that work multiple shifts anyway.

so you don't know how that setup works


In the UK such battery packs are being sold in combination with solar
arrays. Although we do have some cheap overnight electricity tariffs
they have largely fallen out of favour - daytime is a rip-off. They are
mostly a hangover of the "nuclear electricity to cheap to meter" era.

Not sure what that means. What does nuclear have to do with peak rates?

or that


storing it. It's conceivable that on a really sunny day, residential
solar power could generate more power than users could consume.

rather unlikely

But if you are not at home during the day to use it then storing it in a
battery means you get paid for (not) "delivering it to the grid" and
then get to use it later when you come home. This is part of the reason
why solar hot water is a non-starter in the UK. The feed in tariff makes
it more cost effective to generate PV electricity and dump it into your
hot water tank immersion heater since you get paid to do that!

I don't understand what you mean by "paid for not delivering it to the grid"???

why?

ISTR they come in 12kWhr blocks and are notable for being able to
withstand being installed outside in the cold (UK never below -15C).

That's the industrial Tesla PowerPack. They come in different shapes
and sizes:
https://www.tesla.com/powerpack
https://electrek.co/2018/07/16/tesla-powerwalls-new-virtual-power-plant-australia/

Locally, Tesla and PG&E are working at installing a PowerPack at the
Moss Landing power plant:
https://electrek.co/2018/06/29/tesla-pge-giant-1-gwh-powerpack-battery-system/
The justification is that it is cheaper to install these giant battery
packs to deal with the demand peaks, than it is to increase generation
capacity to handle the demand peaks.

We have a lot of gas turbine systems (and pumped storage) for demand
peaks. It is a problem that most generation occurs in the north whereas
the bulk of the consumption is in the south around London and SE.

What is the peak discharge rate that they can cope with in practice?

Which one? The home PowerWall or the utility PowerPack system? I
once found and posted in this group the web site that monitors the
PowerPack, which provided numbers for what was going in and out.
However, I can't find it again. I'll try again tomorrow or day after.

It was the 12kW (or above) system that I was interested in. That would
provide enough capacity to buffer a respectable amount of energy. I am
thinking here of solar 4kW array with battery storage for my home.

12 kW is four times my typical peak usage. Much of the day when the heat or AC is not running my consumption is around 1 kW... peak.

Peak consumption of 3kW is possible but most unusual in the developed world.


My question pretty much amounts to can it support a 3kW discharge rate
or would I always have to take some electricity for peak loads even if
the battery was fully charged.

I haven't looked up the spec, but it would be a pretty crappy battery if it couldn't deliver 3 kW. That's about 30 amps at 120 VAC or 15 amps at 240 VAC.

No it isn't.


You are an amazing conversationalist. Your entire post said nothing at all of substance. Glad you took the time to participate in the conversation... or not.

Rick C.

++ Get 6 months of free supercharging
++ Tesla referral code - https://ts.la/richard11209


Guest

Fri Jan 11, 2019 1:45 am   



On Thursday, January 10, 2019 at 3:44:50 AM UTC-5, tabb...@gmail.com wrote:
Quote:
On Wednesday, 9 January 2019 20:07:56 UTC, gnuarm.del...@gmail.com wrote:
On Wednesday, January 9, 2019 at 4:31:43 AM UTC-5, Martin Brown wrote:

UK MOD made a horrendous mess by applying an old power top up SOP to
newly introduced NiCads back in the 1980's destroying a great many big
expensive wet cell batteries in the process. Being cycled between 80%
charge and full many times left them unable to provide full capacity.
NiFe by comparison would put up with almost any amount of abuse.

Don't know what MOD or SOP are. Since when are NiCads wet cells?

ministry of defence. standard operating practice. 1899.


So care to explain your statements in English?

Rick C.

--- Get 6 months of free supercharging
--- Tesla referral code - https://ts.la/richard11209


Guest

Fri Jan 11, 2019 2:45 am   



On Thursday, January 10, 2019 at 4:29:23 AM UTC-5, Martin Brown wrote:
Quote:
On 09/01/2019 19:53, gnuarm.deletethisbit_at_gmail.com wrote:
On Wednesday, January 9, 2019 at 4:08:09 AM UTC-5, Martin Brown
wrote:
On 09/01/2019 07:45, Jeff Liebermann wrote:
On Tue, 8 Jan 2019 08:50:22 +0000, Martin Brown
'''newspam'''@nezumi.demon.co.uk> wrote:

On 08/01/2019 06:32, Jeff Liebermann wrote:
On Mon, 7 Jan 2019 12:28:49 -0800 (PST), jurb6006_at_gmail.com
wrote:

Going off the grid (not me not now but...) we are looking
at Tesla batteries for energy storage.

Forget that idea. Assuming you mean the Tesla PowerWall 1,
2, or 3, these were not designed to power anything. They
were designed to reduce your peak power usage (time of use
load shifting) thus saving you money on your electric utility
bill.

You have me interested now. I thought in the USA peak power
load was typically in mid afternoon when aircon was at full
stretch and by implication solar panels also at peak output.

http://www.caiso.com/TodaysOutlook/Pages/default.aspx> Note that
solar and wind system, as well as off-grid systems, that provide
their own power, don't appear on the graph. Only those system
that draw power from the grid appear. As such, we have peaks at
about 7 AM and 5:30 PM. The trough at noon is when solar power
is at maximum, which reduces the maximum demand.

Interesting quite how different UK and USA demand profiles are at
this time of year. UK comes up to a level plateau at 0800 until
1600 for the working day and then peaks in the early evening around
1800 as people return home to start cooking and using heating and
lighting.

https://gridwatch.templar.co.uk/

In the US we have a morning peak and a late afternoon peak. Both
peaks are due to the overlap of business and residential usage. In
the summer months the morning peak becomes insignificant to the
afternoon peak because of the AC. Of course this varies somewhat
with region. It is a large and varied country.

I take this to imply that cooked breakfasts are more common in the USA then.


Or maybe we take more baths/showers? In any event, we use more power at home in the morning which has overlap with business.


Quote:
It is actually very mild for winter at the moment around 8-10C so
that there is comparatively little heating demand. It spikes more
when there is a cold snap to -10C (possibly by enough to bring the
grid down). Successive governments have prevaricated for so long
over new build nuclear that things are very borderline now for peak
load vs capacity. They had to pay some heavy industrial users to
drop off grid last winter (people like the electrolytic metals
refiners - ultimate sink load).

You mean during peak times, right? It would make no sense to have
them shut down. Just let them work other than at peak. Most
factories like that work multiple shifts anyway.

No I mean that last year they had to pay heavy industrial users to drop
off the grid because gas availability and electricity generating
capacity were maxed out during "the beast from the East" weather - an
extended cold snap (which may happen again this year).

https://www.ft.com/content/30fa54b2-5e16-11e4-bc04-00144feabdc0

It has got worse since that 2014 article.


So winter time usage? Still, wouldn't that peak at night? Peak energy consumption is a time of day issue. Or are you saying the problem was not the generating capacity, but that there was not enough fuel supply to keep the generators running????

Perhaps you are not digging far enough into the issue to understand that the peak generation limitation generally only impacts certain times of the day. Isn't that clear? It would make no sense to ask heavy industry to shut down at other times.


Quote:
Surely the purpose of a Tesla power wall *is* to store any
excess solar power to use later in the evening when the sun has
gone down (rather than dumping it into the hot water immersion
heater - as is common in the UK).

That's exactly what it's for. You charge up your PowerWall late
at night, when electricity is cheap, and discharge it during the
early morning and evening, when electricity is more expensive.
No solar involved as everything is powered by the grid.

In the UK such battery packs are being sold in combination with
solar arrays. Although we do have some cheap overnight electricity
tariffs they have largely fallen out of favour - daytime is a
rip-off. They are mostly a hangover of the "nuclear electricity to
cheap to meter" era.

Not sure what that means. What does nuclear have to do with peak
rates?

Nuclear needs a higher base load. In the 1960's when nuclear was all the
rage building the power plants it was said by the British government
spokesman that we would have "electricity too cheap to meter".

https://en.wikipedia.org/wiki/Too_cheap_to_meter

(a phrase apparently coined by Lewis Strauss of USAEC)

Economy 7 was a tariff intended to encourage people to use electric
storage heaters overnight on cheap electricity. They were utter crap.


I don't know what an electric storage heater is. You mean they would make heat from electricity and store it in hot water or something similar? We've talked about that here and it takes a lot of water to store much heat. Phase change stores a lot more heat over a narrower temperature range.

I guess the above is a British thing that never made it over hear. I still don't get what any of this has to do with "daytime is a ripoff" or what you are trying to say about it.


Quote:
A quirk of the feed-in-tariff is that you get paid a premium
rate for half of what you generate no matter what you do with
it (insane).

That's a different animal. That's using solar or wind power to
generate electricity, which is then sent to the grid for
"storage" or to be consumed by someone else. In theory, you're
saving the local utility the cost of gas and oil needed to
generate that electricity. Of course that assumes that there's
someone available to consume the electricity you generate, or
that the utility or grid have a way of storing it. It's
conceivable that on a really sunny day, residential solar power
could generate more power than users could consume.

But if you are not at home during the day to use it then storing it
in a battery means you get paid for (not) "delivering it to the
grid" and then get to use it later when you come home. This is part
of the reason why solar hot water is a non-starter in the UK. The
feed in tariff makes it more cost effective to generate PV
electricity and dump it into your hot water tank immersion heater
since you get paid to do that!

I don't understand what you mean by "paid for not delivering it to
the grid"???

You get paid for exactly half of what your PV array produces
*irrespective* of what you actually do with it. Most people turn it into
copious hot water but if you are cunning you can store it in a battery
and use it later in the evening. Hence battery with PV combo sales are
more popular in the UK to avoid using grid electricity.

I think in the US they may well measure the amount of energy you deliver
to the grid and "bank" it or something.


If by "bank" you mean getting paid, then yes. Some states may limit your benefit to simply reducing your bill rather than getting cash, so that I suppose would be like "banking" it. Many places let you get cash, but only for the generation and transmission portion of the bill.


Quote:
Which one? The home PowerWall or the utility PowerPack system?
I once found and posted in this group the web site that monitors
the PowerPack, which provided numbers for what was going in and
out. However, I can't find it again. I'll try again tomorrow or
day after.

It was the 12kW (or above) system that I was interested in. That
would provide enough capacity to buffer a respectable amount of
energy. I am thinking here of solar 4kW array with battery storage
for my home.

12 kW is four times my typical peak usage. Much of the day when the
heat or AC is not running my consumption is around 1 kW... peak.

I meant 12kWh battery capacity.

My question pretty much amounts to can it support a 3kW discharge
rate or would I always have to take some electricity for peak loads
even if the battery was fully charged.

I haven't looked up the spec, but it would be a pretty crappy battery
if it couldn't deliver 3 kW. That's about 30 amps at 120 VAC or 15
amps at 240 VAC.

Regular discharge at C/4 is quite stressful for a battery. 3kW is a
typical peak load in the UK for kettles and electric fan heaters.


Not sure why you say that. Tesla car batteries are regularly charged at a full C if not a bit higher. They are tapered off to a lower rate over 50% charged. The max discharge rate is over 400 kW from my 100 kWh battery. Something like 515 HP, but of course that is sporadic, not remotely sustained.

I thought a standard outlet was 9 amps at 240 volts, that's more like a bit over 2 kW. Is it more like 13 amps? Here it is 1.44 kW, 12 amps at 120 volts (the current for continuous loads is derated to 80%).


Rick C.

--+ Get 6 months of free supercharging
--+ Tesla referral code - https://ts.la/richard11209


Guest

Fri Jan 11, 2019 2:45 am   



On Thursday, January 10, 2019 at 5:05:55 AM UTC-5, Martin Brown wrote:
Quote:
On 10/01/2019 07:03, upsidedown_at_downunder.com wrote:
On Wed, 9 Jan 2019 09:07:56 +0000, Martin Brown
'''newspam'''@nezumi.demon.co.uk> wrote:

Locally, Tesla and PG&E are working at installing a PowerPack at the
Moss Landing power plant:
https://electrek.co/2018/06/29/tesla-pge-giant-1-gwh-powerpack-battery-system/
The justification is that it is cheaper to install these giant battery
packs to deal with the demand peaks, than it is to increase generation
capacity to handle the demand peaks.

Simple gas turbines are cheap, but the fuel cost may be significant,
if you have to run them at more than a few hundred hours each year.

I thought fracking had made gas prices plummet. UK has certainly had a
"dash for gas" in the past couple of decades incredibly short termism.

https://en.wikipedia.org/wiki/Dash_for_Gas


"Cheap" is a relative term. Gas isn't a tenth the cost of other fuels. So the operation of a gas turbine is still dominated by the cost of the fuel when run significantly. Because of the peak demand issue they are often only run for a few hours a day if at all. Then the capital cost of the plant is the issue.


Quote:
The great advantage of battery packs is that it can immediately react
to loss of production capacity of rapid increase in demand. Thus 15-30
minute storage capacity is enough so that you can get gas turbines
started. This also reduces the need for spinning reserve in
continuously running power plants.

I can see that adding a certain amount of this to the mix might save a
bit on spinning reserve wear and tear.


Or completely eliminate the need for some number of peak generating plants.


Quote:
We have a lot of gas turbine systems (and pumped storage) for demand
peaks. It is a problem that most generation occurs in the north whereas
the bulk of the consumption is in the south around London and SE.

While pumping storage is possible only in Scotland, but gas turbines
could be installed everywhere as long as there are nearby pipelines.
The North Sea oil and gas fields feeds these pipelines.

The UK's biggest pumped storage is actually in Wales. I knew one of the
engineers who worked on it. Dinorwig is a 1.7GW plant.

https://www.theengineer.co.uk/issues/march-2015-digi-issue/pumped-storage-a-new-project-for-wales/

It is thirty years old and only now are they thinking about adding more
despite having a far more volatile mix of renewables on the grid.


I wonder about the cost compared to battery generation. Any idea? I expect it would be cheaper if you have the geography for it. But it can consume a lot of land depending on the elevation you have to work with.


Rick C.

-+- Get 6 months of free supercharging
-+- Tesla referral code - https://ts.la/richard11209

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