10kWh LifePO4 DIY Battery Addition..... Here is my write up.

johnbk · 01-01-2023 8:12pm

This is a video I hadn’t seen. It is exactly what I am doing. His experience is very similar too. I need to get bigger cable to speed up the test part. Interestingly the cells look identical but mines are 280 ah.

I paid €1950. I hope I don’t have to go down the road of what he had to do with AE. Will update in the morning when the first cell is complete.

johnbk · 01-01-2023 8:15pm

It sure is a tedious and time consuming process, just to let anyone reading this in the future know.

Should be able to get one cell complete per day - 2 weeks in total.

unkel · 01-01-2023 9:16pm

@johnbk - I thought it was best practice to have the fuse on the positive terminal of the battery? That's what I always do anyway.

Have you a link to where you bought that battery tester? I had one very much like that, never even opened it and sold it on. Must buy one again and keep it this time 😁 Mind it is simply too time consuming to capacity test a 200Ah cell with one of those...

johnbk · 01-01-2023 11:42pm

€ 40,37 15％ Off | 150W DC Electronic Load Tester USB Adjustable Testing Module Power Meter load charger 18650 battery Tools 200V 20A

https://a.aliexpress.com/_mroHszC

unkel · 02-01-2023 12:26am

Cheers, @johnbk. Bought. Can't go far wrong for €39 including VAT and free shipping😁

johnbk · 02-01-2023 2:40pm

Went out to see progress half an hour before test was due to finish. Caught the moment it cut out. 238.85amp hour. Allowing for errors that are bound to be present in this cheap little tester (and my leads that are away too long) - have to say I am delighted.

Have doubled up the leads and testing the next one at 20 amp. Have a heater and cover to keep all around 20c.

johnbk · 02-01-2023 8:06pm

Just realised I ordered 280ah cells not 240ah. :-(

unkel · 02-01-2023 8:14pm

https://www.boards.ie/discussion/comment/120057043#Comment_120057043

Which shop did you buy from? I've heard numerous times that many of those EVE type cells do not have the capacity they are rated for. Still 240Ah is not that bad, that's 86% of the full rating. Also consider you probably had losses discharging it (heat in batteries / cables)

johnbk · 02-01-2023 9:00pm

PWOD store.

Will go flat out now to test remaining cells. Should get 2 a day done now at 20 amp - well within the AE 15 day limit. Will then decide what to do next with regards a dispute or not.

I paid €1950 or €122 per cell that are 240 ah and not 280ah as advertised. If I order 280ah cells from nkon.nl they cost €180. PWOD still are cheaper per amp hour.

Just wonder why do these Chinese companies have to misrepresent the amp hours?

championc · 02-01-2023 9:58pm

The likely outcome will be that you will be offered a full refund ...... if you return them !!!

Personally, I'd just start using them.

unkel · 03-01-2023 12:11am

I guess you didn't wait for any sale? Paid €1360 (€85 per cell) before Christmas and also similar in November for 16 * CALB 200Ah from PWOD official store.

johnbk · 03-01-2023 12:10pm

Going for cells at this price at around 43c per amp hour is one way around the risk of below capacity cells from AE. Being priced so low compensates for any issue with capacity.

If I had got the 280 ah then I paid 44c per amp hour. PWOD delivered in a quick 7 weeks in my case. Also packaged really well. Cells are pristine with only one cell with a slight bulge. Only problem is the capacity.

I have another 14 cells to test (second one is also 239ah) before I decide what I will do on AE. I have used the dispute before and it works really well in my experience. There will be many possible outcomes from a dispute.

At the end of the day, I want to make a DIY lifepo4 battery. At this capacity, a 12kwh battery is still on the cards for less than €2,500.

IMO it is safer to assume that cells on AE are not grade A new cells but rather grade B. What I feel is important here on Boards is that those following this thread can consider my experience and purchase with this in mind.

johnbk · 03-01-2023 12:41pm

Changing subject slightly, can these cells be built on their side? What I was thinking was to arrange them the normal 8 side by side but to have them on their side with the poles facing out. I want to mount them in a unit directly onto the wall beside the inverter. This way the final battery will be much closer to the wall.

championc · 03-01-2023 12:45pm

You could do. You'll need good brackets and anchors as 16 cells would be quite heavy

johnbk · 03-01-2023 1:27pm

Definitely need good fixings. My gut says no to being on their side as the vent is on top between the poles. Another option would to have 8 over 8 standing up with a cable connecting cell 8 to 9 instead of a bus bar. This cable would need to be pretty big to avoid voltage drop or resistance.

With regards the frame, for holding the cells, I’m more of a steel person than a wood person. There is a lovely wood example that is current on diysolar forum. I like how the Seplos is mounted in particular. https://diysolarforum.com/threads/48v-280ah-diy-battery.52600/

Opinions greatly appreciated.

slave1 · 03-01-2023 3:17pm

They are fine on their side, just not upside down with these cells, I have 32 of the 200Ah cells in a vertical row on a 2.4m shelf no problem and it will take the weight of another 16 if I ever reposition them sideways. You just have to make the shelf out of sturdy material and over anchor the crap out of it.

unkel · 03-01-2023 3:26pm

I'd be with @championc - just start using the cells. I've had many disputes on AE and every single one of them I won and got a full refund. But disputing very cheap grade B cells at near enough 90% of their rated capacity is a bit over the top imho. Up to you though of course, you could well get a refund if you decided to to that route.

slave1 · 03-01-2023 4:17pm

You'll likely find your recourse stipulates you are responsible for return of goods, this alone is endgame and something you took on the chin when ordering (consciously or not)

unkel · 03-01-2023 4:31pm

https://www.boards.ie/discussion/comment/120060274#Comment_120060274

I've never had to return a single thing for all the refunds I got from AliExpress. Sometimes a white lie helps stating that it is illegal to post something (like batteries) out of the country. Even if the product doesn't have a battery in it 😁

slave1 · 03-01-2023 4:56pm

Neither have I because all my purchases were "returns not required", you just can't get any seller doing this with the CALB batteries though unless some scammer pops up a shop

munsterfan2 · 04-01-2023 8:35pm

My order arrived today ( 4 x CALB 200ah). Charging one with bench charger, will connect to discharge tester and update

slave1 · 04-01-2023 8:55pm

Lots of deliveries last day or so, great to hear

BuzzFish · 05-01-2023 9:04am

OP here. Capacity if my pack is firmly 5.5kwh but lots of testing has let me to two duff cells so 4 new ones on the way (from PWOD this time). Ordered on Dec 28. Label received already. I'll update in delivery times fyi.

munsterfan2 · 05-01-2023 7:45pm

1st PWOD Cell tested, 146ah capacity. Will test next one and open a dispute

championc · 05-01-2023 8:24pm

Well annotate images, so the viewer / adjudicator is clearly seeing what you are claiming

johnbk · 05-01-2023 9:22pm

https://www.boards.ie/discussion/comment/120070522#Comment_120070522

I can’t see what amps you tested at. If you did at 20 amp, there is a possibility you would have heat loss through your blue cables (even though you have them nice and short), and enough voltage drop on the cables to make the tester stop early.

They could be heavier. Any decent electrical wholesaler will have 6, 10, 16, 20 mm on a roll and will sell even a few inches. Although not very flexible, will work just as well as automotive cable.

One way to check for any voltage drop when all is hooked up and before you start is to check voltage at battery terminals and at the tester terminals. Then do it again when you have the tester running.

I have 6 cells tested now and so far they are all around 238/280 amp hour. I have another that I am going to retest before I make note of it. I would say PWOD are sorting batteries on internal resistance at 3.3v (about 80% charged) in my case and do not spend the time doing the full load test. So if my theory is correct, you should be hitting 170ah.

unkel · 05-01-2023 9:34pm

https://www.boards.ie/discussion/comment/120070522#Comment_120070522

What was your starting voltage? Was it really and truly fully charged? As in hooked up to your charger providing 3.65V until it went all the way down to zero amps and was taking no more charge? Also discharge is to 2.5V, not 2.6V (not that it matters more than a fraction of a percent, but your proof needs to cover the full allowed voltage range as per the spec sheet)

And your cables look very skinny. How much (heat) losses went into them because of high resistance? Any of that would have taken away from the capacity your tester shows. This could well be 20%, depending on the amps you were discharging with. How many amps was that? This also has to match the C rating of the spec sheet, otherwise you don't have a leg to stand on.

And link to those cells on AliExpress. They are different from the blue ones that most of us have. Sinopoly is well known, but your cells look second hand?

johnbk · 05-01-2023 11:51pm

https://www.boards.ie/discussion/comment/120070925#Comment_120070925

Just notice the test length at 7 hours so you went with the 20 amps. I think you need to get down to less than 1% voltage drop on 0.2 meter length cable between the tester and the battery and you need 8mm2.

I know in my testing, I am trying to squeeze every last amp hour out of the cells as I really would prefer getting on with my project to the hassle of an AE dispute.

johnbk · 06-01-2023 12:01am

Also, you have the cut off at 2.6v. I initially did this too, buy the pwod sticker on the side of the battery clearly states 2.5v in my case so I made that change on the tester.

I have noticed virtually no difference by the way with this change.

munsterfan2 · 06-01-2023 12:55am

https://www.boards.ie/discussion/comment/120070977#Comment_120070977

Starting voltage was 3.65, bench charger down to .0xx amps, was discharging at 20amps, will drop to 10 for next one and get some thicker cables. https://www.aliexpress.com/item/1005004266343456.html?spm=a2g0o.order_list.order_list_main.5.591e1802i5TQvt was the link for the cells, just went for black to easier differentiate from existing 16 blue cells. Will adjust final voltage to 2.5 but at that stage of curve there is little / no capacity. 20a is .1c so should not be an issue, spec sheet lists .5C and 1C.

10kWh LifePO4 DIY Battery Addition..... Here is my write up.

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