#Battery1.0 Capacity Test on 4 year old EVE 'A-Grade' battery. Normal or bad?

We finally have a closer look at the capacity of the Battery 1.0 which I bought 2 years ago (but we found out it was already two years old at this point). I managed to test 9 out of 16 cells over the last week and present the result here in this video.
So, the question is: Is the result normal or bad?

All results are in this spreadsheet here. I will continue adding data over time when I have more results:

ZKE-Tech EBC-A40L Battery Tester with 40A charge/discharge and full PC connection for curves and data logging:

EVE LiFePO4 cells certified and storage grade cells:

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[OffGridBasement]

I'm sure everyone is saying it, but cold vs warm test is definitely required to see true test between cells at different temps! Thanks for the videos! I can't tell you how much I've learned from you and this channel! Thanks Andy!

[millycarrington]

What about taking cell 6 and the tester into the house, let them warm up to room temperature and repeat the test, that should show if temperature is a contributing factor.

[struc]

Very insightful video Andy. Congrats on topping 35, 000 subscribers!

My thoughts... For the extra amount you would pay for top tier A+ batteries, you can buy a 2nd (and probably 1/2 of a 3rd) set of storage grade batteries. You're doing it the right way. The capacity, for the money, will always be 2x that of A+ grade batteries.

[upnorthandpersonal]

Instead of just randomly speculating, let's do some math. For one, the EVE datasheet states to expect a cycle life of >=2500 without fixture ('compression', yes, I know...) and >=3500 with. So we already increase our normal degradation by 28% by not having the cells in a fixture. Secondly, find some temperature discharge curves for LiFePO4 for example from Nordkyn et al. You should expect at least a drop of 2% at your current temperatures. Finally, a couple percent calendar aging. This also depends on temperature: the higher the temperature your batteries sit at, the faster the degradation - since you're in sunny hot Australia.... The literature has several models on this, but there are numerous variables I can't account for, but a couple percent is not out of the ordinary over the 4 year life since manufacturing. Based on all of this, 5%, or even 8%, doesn't sound bad at all. It would be good to do a capacity test again at 25C to at least remove that variable...

[edwardvanhazendonk]

Thanks for testing and commenting why it happens. Good luck with the other tests and videos, always happy to watch them.

[Aan]

It is hard to say if the are bad.
This is seen from the standpoint of View, I purchased 44 Lifepo4 cells Thunder Sky in 2011 160 Ah.
When they were new they had about 180 Ah.
Today it has 155 Ah.
These cells has been mistreated in many ways.
Thanks for your open and honest videos. 👍

[solarchumboacido]

Thank you so much for taking this test and showing the results after years of use.

[gannas]

I appreciate your transparent and objective approach. It would be interesting to see if this changes during the summer. Although that rate of degradation isn't necessarily alarming given how much time has passed, in my opinion. Still far better than other battery systems I have used.
Edit: imagine getting these results if you had paid that 50-70% premium for the "real" A-grade batteries! Ooof!

[harrycrawford]

Warm test required I think, even if it’s just one cell to see what difference temperature plays.

[loganv]

Excellent tests. Excellent thoughts. Excellent conclusions.
Please keep up the good work.

[onthelake]

I think your results are great considering the COLD temperature, I would expect at least 5 % loss from the cold, more actually . But you made a good point, we need to document the temperature of the cells when taking data points for the spread sheet . Thanks for reminding me.

[krg]

Great testing. Fortunately I started as you with a spread sheet. With top equipment now, , As I get batteries completed I'm going to start a cell swapout/testing. Keeps me busy and batteries in top condition. Older cells will be matched and put together in a battery. No hurry using the ebc-a20. One cell purchase as needed I consider maintenance costs.

[loucinci]

You could always sell these batteries as "Used grade B". Lesson here is have a good way to test the batteries you purchase and ALWAYS test capacity when you purchase. I just noticed your hard drive magnets holding your pliers on the bench wall - LOL. Love it. Perhaps, use a heater to warm one battery to "summer time" temps and re-test? I wonder if the capacity would increase. These may be summer-time-only batteries. Thanks for sharing

[IanNature]

Thx so much you‘re so great, everything i ‚ve learned about battery technix in that short time is because of you doing that 🐬

[MrEroshan]

My CALB lifepo are 6 years old in my full time RV compressed. My bank is 8 cells 180 amp/hr ea. for a bank of 360 amp/hr at 13.2 volts. I tested mine 2 months ago. They are always within 10 millivolts at full charge. They have lost 3 percent in 6 years. I love CALB because of the robust case and the large terminal connections. My EVE battery has already stripped out 2 connections and runs almost 80 millivolts delta after only one year, they are compressed BTW.

[madsskov_dk]

Excellent video. You are a goldmine of information!
Please heat up a couple of cells and simulate a “summer” test.
Also, if you can put them back into service, more valuable lessons will come from it.
Thanks for sharing your efforts!!

[luispendragon]

I really beleive the deviation on your results respect standart conditions is noticeable but not abnormal. 11°C is starting to be quite cool for the batteries. So wirhout another CRAZY week of testing would accept those results as within the normal degradation values. Thank you for such a Crazy testing!! Again...;-)

[aliceromanova]

Thank you Andy!😚 I hope we will can see new test this batteries soon

[imag]

Thanks for the video.
I'm capacity testing lifepo4 batteries everyday and using different testers. These results helps me understand how critical the environment conditions and testers are.

[Wrenchen-with-Darren]

I agree with your numbers, not bad at all. Given the temps, your use, as well testing at home and the expense of cells. I think your.... right on.