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

bullit_dodger · 04-04-2023 6:28pm

The test at 10min in was more like 200 watts test unkel (turned out to be 70A at 2.7V), which really isn't that unusual. 16cell x 200 watts each = 3200 watts which is what you'd expect most battery banks to be able to deliver, and deliver regularly. If you had a few dodgy cells with that kind of voltage drop, that could trigger issues.

Sure dragging down 250A, I can't see anyone ever wanting (or needing) that. But 200watts from a cell - yeah, definetely I could see that, and suspect that your own batteries do that everyday. No?

The point here though (and I'd be conscious that you've a lot of expierence in this space) is that it's often difficult to discern the actual truth. Off grid garage saying that you can ignore A/B, Sun Kits saying that it does matter. These guys test stuff regularly. Hard for me to call who's right and even the truth maybe somewhere in between. For us end users trying to get a handle on things, it's often a sample size of 1. You order a batch from PWOD and they are good = excellent supplier. Order another batch and they are bad = terrible supplier "avoid like the plague". Hard to generate (correct) opinions from our side.

Again (as before) I'm not suggesting Grade A are the way to go - infact in my own case I think I'd order 17-18 Grade B, so I'd have 1-2 spares then for the "bad kid in the class", but perhaps capacity isn't the only thing that should be evaluated?

unkel · 04-04-2023 6:52pm

Ah I'm not denying he clearly had a bad cell there. But 200W is not nothing either, like you say it's 3.2kW and that's more than i.e. a ME3000SP can deliver. And a voltage drop is not a problem as long as the cell doesn't go below 2.5V or whatever you've set as the minimum for the BMS to cut off. And that cell isn't typical, it's knackered.

I don't disagree with anything the guy was saying, but in my book he doesn't really make a good business case for buying grade A / automotive cells for a 16S home power wall. It's simply a waste of money not giving you any better return (presuming capacity is the same as Andreas tested to be the case). For a 4S campervan system with a high power inverter attached to it, maybe.

munsterfan2 · 04-04-2023 7:51pm

https://www.boards.ie/discussion/comment/120439607#Comment_120439607

I have a neey active balancer also... I think if you can get the CALB at a good price and a reasonable capacity they are a great option, unfortunately not my experience.

unkel · 04-04-2023 8:25pm

I had never heard about this Oyear shop on Aliexpress. Perhaps a dodgy outfit. I guess you either didn't see the usual recommendations for PWOD / OYE in this forum or you just went for the cheapest or both? A few of these recent reports on boards like yours about the CALBS (even from PWOD) has us lazy owners question what the capacity of our cells is!

Sorry for your troubles with the batteries anyway, I guess there is always something good coming out of these things and you know a helluvalot more about batteries than you did last year 😁

graememk · 04-04-2023 9:09pm

https://www.boards.ie/discussion/comment/120441075#Comment_120441075

I think it was a misspelling of oye store or auto correct 😂

unkel · 04-04-2023 10:01pm

Ah get ya 😁

I think someone here found out recently that OYE is the same company as PWOD, and they obviously sold sub-par cells, so that is worrying.

johnbk · 04-04-2023 10:07pm

Great discussion. It’s what I like about Boards the most.

Anyone following this that spends the time and reads the entire thread throughout on going a diy battery route should have all the information to make an informed choice on where to buy cells.

As for myself I feel I still have to see more evidence on people’s experiences with non-Chinese suppliers before I make up my mind for the next purchase and whether the premium is worth it and that this premium guarantees the capacity.

johndoe11 · 06-04-2023 7:53am

That's a great job. Just wondering which BMS is the Seplos BMS 150A with LCD and Bluetooth in the AE Minerals store? I don't see the Seplos brand mentioned.

johnbk · 06-04-2023 7:36pm

Here’s the link. Be careful with selecting and adding to cart as they have all the options here inc Bluetooth

I see the one you want is €248.96

€ 128,01 48％ Off | Seplos Smart BMS 8S 13S 14S 15S 16S 50A 100A 150A 200A 48V CAN/RS485 With Bluetooth LiFePO4 Lithium Battery Protection Board

https://a.aliexpress.com/_ms6o8W0

munsterfan2 · 07-04-2023 8:33am

Ran the capacity test with same equipment and at 20a (when this got poor results I was asked to test at 10a, asked about wires, testing equipment, whether batter should be vertical or horizontal temperature etc, basically any excuse.)

Need to recharge to approx 100ah so it is similar to what it arrived at and then build and let the neey take care of top balancing :-)

bullit_dodger · 07-04-2023 9:28am

https://www.boards.ie/discussion/comment/120450470#Comment_120450470

Not sure if I'm reading this right, but from the picture is that not saying it's capacity is 306Ah?

What are you expecting? It's good, no?

unkel · 07-04-2023 12:10pm

https://www.boards.ie/discussion/comment/120450636#Comment_120450636

It's good with the EVE cell which gave him full capacity even though he is using a flimsy cheap tester, his cables aren't thick enough for 20A (10A per cable) the position and temp of the battery mightn't have been perfect either. Still all good with the EVE cell

Where as the sellers of the CALB cell he had were using all of the above as excuses for why he got poor test results...

I liked your sarcastic post, @munsterfan2 😁

munsterfan2 · 07-04-2023 12:47pm

https://www.boards.ie/discussion/comment/120450636#Comment_120450636

Yup, delighted with 306a for 300a cells.

bullit_dodger · 07-04-2023 2:23pm

Ahh right, gotcha :-) That was lost on me - although I also did get a chuckle out of the battery orientation. Turn around three times, touch your nose etc.

Although to be fair, I'd be pulling 50-60A as a test. Lets assume a ME3000 so you'd be limited to 3kw. Each cell of the 16 cells would need to be delivering 180w or so at 3v ~ 62A to give you that 3kw. Those tests of 10A that they ask people to do are fairly benign and not a "real world" scenario if you ask me.

Sure, they'll "prove" capacity......but is that the only comeback that people have with them? (I ask not knowing)

munsterfan2 · 07-04-2023 9:18pm

https://www.boards.ie/discussion/comment/120451616#Comment_120451616

Yup, after the 20a tests were only 150ah ( for the 200ah CALB) they asked me to repeat at 10a, then (same result) so they asked for temperature, then said both of my testers must be faulty and then said the said the cell needed to be upright :-) Also complained as during one test after the 2.5v cutoff the cell read 2.4x for a few readings before rising up again to about 2.8v and said this invalidated the warranty. I got a partial refund on those 4, but on the OYE cells it had gone past the dispute date.

unkel · 07-04-2023 9:52pm

https://www.boards.ie/discussion/comment/120452831#Comment_120452831

Out of interest, what refund did you get on the CALB cells (from PWOD?) that tested at 150Ah?

munsterfan2 · 08-04-2023 7:26am

https://www.boards.ie/discussion/comment/120452979#Comment_120452979

€48 - original order €378

S' · 13-04-2023 1:18pm

Any reason why battery charge is limited to 2.6kW charge? Never goes above this, exports to grid when cylinder is heated.

20kWh pack with Seplos 200A BMS

championc · 13-04-2023 1:36pm

Must be limited by the inverter ??

S' · 13-04-2023 1:50pm

I can see on the inverter that the charge limit is 50A but when I change this setting higher the inverter overwrites back to 50A.

Is it not the BMS that controls charge/discharge rate?

SD_DRACULA · 13-04-2023 2:16pm

Known Solis issue, I had to get them to manually push it back up to 100a remotely or if you can push it via modbus it might stick.

poker--addict · 20-04-2023 8:38pm

My capacity tester has arrived.

for the newbies like myself, a guide;

https://youtu.be/3dmWqHR7b9w

https://youtu.be/TQ17yu5zhZ0 (Off grid garage)

BuzzFish · 21-04-2023 5:54am

How long are PWOD orders taking to deliver these days? Ordered on 17th March.

championc · 21-04-2023 6:12am

Always been approx 10 - 12 weeks

BuzzFish · 21-04-2023 9:09am

Just for anyone else ordering from PWOD they gave me the best tracking site to use for Lines/DPD carrier and I can see the status of the ship my batteries are on now....

http://hst56.kingtrans.cn/WebTrack?action=list