Battery comparison for energy storage. What bat to include?

[electrodacus]

Hi I'm working on a new youtube video where I will be comparing Lead Acid with Lithium (different chemistry) for energy storage.
I will put an accent on the price / energy stored during battery life.
Most only compare price / battery capacity and that is not the right approach.
Price divided by energy that a battery can store during the life time of the battery is a much better number even if is a bit more complicated to get to.

I live offgrid and the house is powered by solar and wind. My main battery is a GBS 8s cell 100Ah and I have a smaller backup battery that is made of 8s cell A123 System 20Ah

One example for the A123 System will be like this
I payed 30$ for one A123 System cell (China Alibaba not sure about the cell provenience but looks genuine or a very good copy then again it my be a reject but is still quite good)
In theory has a 20Ah x 3.2V = 64Wh capacity most just divide the price by this number and compare battery price in this case 30$/64Wh = 0.47$/Wh but this is not good in any sort of comparison unless is just for an UPS that may never be used and then this number + the shelf life of the battery may be sufficient.

Else you will need more info to make this calculation (ex A123 System 20Ah cell)
(20Ah x 3.2V x 3000 cycles x DOD x charge discharge efficiency ) the charge discharge efficiency will depend on the application and discharge rate but is way better on any lithium than it is on a Lead Acid. Then there are other aspects that can be considered like the capacity degradation in this case it seems to be linear and the A123 still have about 90% of the initial capacity after 3000cyclse of 100% DOD
http://www.raceyard.de/tl_files/Newsletter/Dateien/A123-AMP20-M1HD-A-1-Data-Sheet.pdf

So 30$/ (20Ah x 3.2V x 3000 x 100% x 0.95) = 30$ / 182.4kWh = 16.5cent /kWh stored during the life time of the battery.
Let me know what you thing about this and what battery I should include in this comparison.
The battery needs to have a spec where at least this few parameter are provided.
Degradation chart with the number of cycles and degradation in percentage or Ah and the conditions this test was performed like the DOD and charge/discharge rate, similar to the last graph in the A123 20Ah spec.

It has been two years since I made the research for my batteries not sure how much has changed since then what new batteries are available.
I know that for mobile applications things are different compared to stationary where energy density is not important.
I can use Li-ion (LiCoO2) charged at 3.9V and make it last 8x more with 60% of the original capacity thus making that battery 5x less expensive in stationary application where weight of the battery is not an issue.
I'm also working on a fully programmable BMS is open source but only support 8 cells so not sure how much interest is in here for something like that it can be modified to work with double that 16 cells but I will not need something like that so I will not design one.

 

[Hillhater]

There is a lot of buzz about using reclaimed EV packs for solar/wind storage, so comparison data using those would be useful.
IE:-..
16kWhr Volt pack
24kWhr Leaf pack
85kWhr Tesla pack
But getting reliable and accurate data for cycle life , cost, etc ..may be tricky, though much of it is scattered around various forums.
And obviously as a base line data from using traditional deep cycle Lead Acid packs should also be included.

 

[electrodacus]

There is a lot of buzz about using reclaimed EV packs for solar/wind storage, so comparison data using those would be useful.
IE:-..
16kWhr Volt pack
24kWhr Leaf pack
85kWhr Tesla pack
But getting reliable and accurate data for cycle life , cost, etc ..may be tricky, though much of it is scattered around various forums.
And obviously as a base line data from using traditional deep cycle Lead Acid packs should also be included.

Thanks for the feedback.
Yes I've seen the buzz around this battery packs but there is no way of getting them unless from a crash car.
As for data about cycle life I prefer data sheets from manufacturer.
Is funny I was just checking a data-sheet from Surrette or Rolls battery as they are called now and all the graphs in that PDF where great resolution except for the one with life-cycle that was completely unreadable hope to find that graph somewhere. And the Trojan another popular battery dose not give good data just show a cycle life vs DOD but seems like a linear one not possible and also no word on what is the renaming capacity after this nr of cycles (probably 50%) also nothing about the charge, discharge rate used for this life cycle test.
As for lithium is almost impossible to get an official price for this batteries and most are just small 18650 cells from large manufacturers.
At least you can find a bit more detailed data about the life cycle tests.
I will not be able to use data from individual DIY tests not made by the manufacturer since there will be a lot of comments about the validity of those tests.

 

[Hillhater]

Finding "certified" data for any cells is difficult,..especially for life cycle tests.
And there does not seem to be any real standards that these people follow for much of the tests anyway.
The car packs do have a "life expectancy" often quoted by the sales guys, but that is hardly scientific or reliable.
The Tesla , (18650 cell) type packs do have much more data available , and may well be a good format to focus on as Tesla are openly selling into the Solar storage market already.
http://qz.com/151801/why-solarcity-and-tesla-are-going-to-replace-your-utility/
One problem i see is again around the "life expectancy" estimates, which you are basing on the tested "Cycle life" data.
Theoretically, based on typical tests, Lead Acid has poor cycle life, suggesting just a few hundred cycles at best.
But its obvious in practice that "normal usage" means that most LA batteries last years in daily use. I know one guy who has a large bank of DCLA cell on a solar set up that is over 10 years old and showing no signs of deterioration !
So, i suspect "real world" life expectancy is heavily dependent on actual usage patterns, depth of discharge, rate of charge, etc, etc, ..which makes me wonder if you can actually draw any real conclusions based on any available cycle life data ?

Incidentally, i assume you have seen there is an "alternative Energy" forum on this site.
You may get more input there.

 

[electrodacus]

Finding "certified" data for any cells is difficult,..especially for life cycle tests.
And there does not seem to be any real standards that these people follow for much of the tests anyway.
The car packs do have a "life expectancy" often quoted by the sales guys, but that is hardly scientific or reliable.
The Tesla , (18650 cell) type packs do have much more data available , and may well be a good format to focus on as Tesla are openly selling into the Solar storage market already.
http://qz.com/151801/why-solarcity-and-tesla-are-going-to-replace-your-utility/
One problem i see is again around the "life expectancy" estimates, which you are basing on the tested "Cycle life" data.
Theoretically, based on typical tests, Lead Acid has poor cycle life, suggesting just a few hundred cycles at best.
But its obvious in practice that "normal usage" means that most LA batteries last years in daily use. I know one guy who has a large bank of DCLA cell on a solar set up that is over 10 years old and showing no signs of deterioration !
So, i suspect "real world" life expectancy is heavily dependent on actual usage patterns, depth of discharge, rate of charge, etc, etc, ..which makes me wonder if you can actually draw any real conclusions based on any available cycle life data ?

Incidentally, i assume you have seen there is an "alternative Energy" forum on this site.
You may get more input there.

Most build over sized Lead Acid battery banks for many reasons. One they do not like high discharge rates under 0.2C usually then they do not like high DOD usually much less than half the available capacity. So with a good deep discharge Lead Acid battery that can do 500 cycles at 50% DOD and is most of the time discharged only 20 to 30% will make this last for maybe 5 to 7 years in an off-grid application. But none of that is important what is important is at the end of the life how much energy you got out of that battery and what was the initial investment so that you get the price/kWh stored.
If you make the same initial investment you can get a lithium battery that will last at least 2x to 3x longer so that the price / KWh stored will be smaller.
Most people think Lithium batteries are much more expensive then Lead Acid when the reverse is true that is because they use the wrong data when they compare them.
There are some other advantages one of them is that they (Lithium) can be stored inside with no venting to the outside like Lead Acid. If you have your Lead Acid outside in the winter you can get at best 60% of they rated capacity and the life will also be affected. If you have them inside and vent them you will louse a lot of heat from the house not an option that heat can cost more than the battery.

 

[dnmun]

i don't understand why you feel a need to vent the batteries. seems like they can live in the house too.

but the cost of lead in the future is gonna continue to increase and the cost of lithium is gonna continue to decrease.

you don't need to spend up on A123 since you can buy reasonably high quality 2C lifepo4 pretty cheap already.

i have told people to jump on this, down to 3 left now:

http://www.ebay.com/itm/181148272576?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

you can split it into two 8S sections and use your fancy BMS on it.

 

[major]

Let me know what you thing about this and what battery I should include in this comparison.
The battery needs to have a spec where at least this few parameter are provided.
Degradation chart with the number of cycles and degradation in percentage or Ah and the conditions this test was performed like the DOD and charge/discharge rate, similar to the last graph in the A123 20Ah spec.

Take a look at the EnerDel product. Here is a place to find the charts you want. http://www.enerdel.com/wp-content/uploads/downloads/2012/10/CE175-360-Moxie-Prismatic-Cell_ENERGYSTORAGE_Final.pdf I happen to have some new cells for $0.31/Wh. There are also EV parts dealers offering these cells for a bit higher.

 

[electrodacus]

i don't understand why you feel a need to vent the batteries. seems like they can live in the house too.

but the cost of lead in the future is gonna continue to increase and the cost of lithium is gonna continue to decrease.

you don't need to spend up on A123 since you can buy reasonably high quality 2C lifepo4 pretty cheap already.

i have told people to jump on this, down to 3 left now:

http://www.ebay.com/itm/181148272576?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

you can split it into two 8S sections and use your fancy BMS on it.

Lead Acid will vent Hydrogen even the sealed ones so it not legal or safe to have them without venting in a house.
Actually the price of the ones in your link is the same as what I have payed two years ago on my A123 20Ah cells you just get the charger that is of no value to me and I'm guessing those cells are far from the A123 System in quality.
Do they have a datasheet? I do not think is worth buying a battery with no datasheet at any price.

 

[electrodacus]

Let me know what you thing about this and what battery I should include in this comparison.
The battery needs to have a spec where at least this few parameter are provided.
Degradation chart with the number of cycles and degradation in percentage or Ah and the conditions this test was performed like the DOD and charge/discharge rate, similar to the last graph in the A123 20Ah spec.

Take a look at the EnerDel product. Here is a place to find the charts you want. http://www.enerdel.com/wp-content/uploads/downloads/2012/10/CE175-360-Moxie-Prismatic-Cell_ENERGYSTORAGE_Final.pdf I happen to have some new cells for $0.31/Wh. There are also EV parts dealers offering these cells for a bit higher.

Thanks for this. I did not know about this guys.
Where can you get this cells?

 

[major]

Thanks for this. I did not know about this guys.
Where can you get this cells?

http://endless-sphere.com/forums/viewtopic.php?f=31&t=50535
I believe the link to evolve is in that FS thread. Here it is: http://www.evolveelectrics.com/Enerdel.html

 

[electrodacus]

Thanks for this. I did not know about this guys.
Where can you get this cells?

http://endless-sphere.com/forums/viewtopic.php?f=31&t=50535
I believe the link to evolve is in that FS thread. Here it is: http://www.evolveelectrics.com/Enerdel.html

Shipping seems to be a real problem with Lithium.
I got my A123 cells form China delivered by Canada Post. The large 100Ah 8 cell GBS where from a small company in Canada delivered with Canada Post in a heavy wood box.
I think each city should have his own battery manufacturing plant same for solar PV panels