Solar PV battery options

DrPhilG

Also there's this notice:

With OYE they stated that the cells were shipped from Poland and all duty was included. This seems to indicate that I'll be liable for the vat on import.

DrPhilG

I wonder if a Northern Ireland delivery would be any cheaper or easier re tax.

graememk

https://www.boards.ie/discussion/comment/120045237#Comment_120045237

NI Is technically EU customs wise.

The Cells i got in April & Nov both had the VAT reduced at checkout, but landed without issue, the ones that were got on 11/11 seem to be landing fine.

Keep a watch on the prices, I did see 1400 last week for 16. (at checkout)

unkel

I paid €1364 on the 23rd. That's with the VAT taken off, but hopefully not charged upon delivery - like all my other CALB deliveries from PWOD before 😁

noelocon

Anybody have any advice on what off the shelf 10Kw battery system to get if I already have a Sofar Me3000. I HAD a diy setup (16s 200Ah) until recently but alas something shorted when I was wiring the bms and the entire thing sparked up and a number of cells caught fire. My better half has (rightly) put her foot down and now wants something non-diy for storage.

unkel

https://www.boards.ie/discussion/comment/120050152#Comment_120050152

😮

Did you not have your spanner taped up? Glad you're ok and I can see where she is coming from. Sorry, have no advice on pre made packs.

DrPhilG

Bloody hell.

What kind of cells did you have? I thought LiFePo4 was damn near unburnable?

noelocon

Yea I got them from Ali last year. No idea what happened tbh as I had just turned around and it started sparking and then boom. No tools or anything near them at the time except for the bms cables that I was wiring. I'd just top balanced them but there was still .3 of an amp to go before they were full. What's even stranger is that three of the cells went up and then the fire damaged a few more. It was all over in seconds but no idea what the root cause is.

Update: actually from looking at the burn marks I wonder if the bus bars were the cause.

graememk

https://www.boards.ie/discussion/comment/120051843#Comment_120051843

Dead short.

The copper bus bar burnt out, stopping the short. (1000A slow blow :P)

edit:

Also Id say you didnt have the busbars tightened down fully, hence the arcing and sparking.

That last bus bar joining the two sides on the the bms side shoudnt have been there. that was your mistake.

That is where your +ve and -ve to the inverter was meant to go.

cells didnt burn beacuse of over current, they burned because of the heat/arcing of the bus bars on the terminals.

championc

https://www.boards.ie/discussion/comment/120051843#Comment_120051843

You should only have used 15 of the busbars. You have one linking the two sides together at EACH end. So you made one big loop.

So in fact, it just shows ultimately how safe these cells are.

Geeyfds53573

Gosh yep you have joined up the main + and - - can the batteries not be salvaged

graememk

This was the video was looking for.

The amount of current a bus bar can carry depends on how tight the bolts are.

This is not a dead short though, but a full and empty cell:

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

noelocon

https://www.boards.ie/discussion/comment/120052016#Comment_120052016

Shite....I was so focued on gettin the BMS wired that I must have put on that busbar by mistake knowing that the BMS leads were supposed to go there.

thanks @graememk it's good to know what caused it.

the question now is how do I determine if the batteries are worth salvaging

graememk

https://www.boards.ie/discussion/comment/120052078#Comment_120052078

You'll not make that mistake again!

Depends on if any of the bolts are welded in, Id say it looks worse than it is.

Look at the short circuit tests from gwl :

https://youtu.be/Qzt9RZ0FQyM?t=183

LFP just vent, yours didnt get near that,

What voltage are they sitting at now? Possibly some reduction in capacity due to the v high current but if are all reading the same voltage id say they would be fine, Id give them a wipe though!

noelocon

Yea they're all sitting at 3.31-2 volts. No swelling but 4 of them are heavily damaged.

I can get 4 new ones from Ali arriving in March. Is it possible to setup the existing 12 and use them or will the voltage not be enough.

championc

You'll really need 16 tbh, to also use and have the safety of the Seplos.

Get a brass brush or emery paper and clean up the terminals. Will a bolt screw into those connections ? Is the one with a bolt there welded into place ?

buzz11

https://www.boards.ie/discussion/comment/120051843#Comment_120051843

The jerry can & gas cylinder were ready for the mega BBQ !!

graememk

https://www.boards.ie/discussion/comment/120052359#Comment_120052359

Even a file to take the worst off it off.

If you can clean them up, I'd say they are useable.

15s is usually as low as you can go voltage wise but not sure if the seplos supports it.

Maybe some wd40 to clean off the soot.

championc

The plastic scorching could be purely cosmetic. The rugged plastic casing is possibly one of the main reasons as to why we have promoted the used of these 200ah cells over the other aluminum cased 280ah cells

slave1

https://www.boards.ie/discussion/comment/120052078#Comment_120052078

Thanks for sharing your misfortune, it’s a great learning for the community as a whole and you now realise what your mistake was. Stay with it and let’s see this pack rebuilt🔗

noelocon

So I spent some time going through the 4 most damaged cells and other than a few welded screws they seem ok. The concern I have is the state of the terminals as they're now not even and I wonder if that'll cause any issues as there's still melted metal on them.

All the threads seem fine though.

championc

Get a dremell or emery paper and smooth them off. They'll be grand 👍

DrPhilG

Lads we're missing the real issue here...

His missus laid the law down and told him no more DIY!

unkel

https://www.boards.ie/discussion/comment/120053614#Comment_120053614

His job to change her mind so :-)

Nelbert

Is it still DIY at this point? He's help from the experts here.....

Loopholes.....

graememk

https://www.boards.ie/discussion/comment/120053662#Comment_120053662

"learning experience"

Ive fried 1, maybe 2 balance boards.. thankfully they were cheap, so when it came to the bms.. the leads are triple checked. and checked again.

unkel

Nearly fried a cheap Daly BMS once. Balance connector started to smoke, pulled it out quickly. Got lucky. Indeed double and triple check the voltages now before I connect.

championc

https://www.boards.ie/discussion/comment/120053614#Comment_120053614

That was when he had no idea as to how it happened. But now he has the answer to that question.

But it also shows how safe the rugged casing of the CALB cells are.

ELM327

https://www.boards.ie/discussion/comment/120053816#Comment_120053816

Yes I think we all do that. I'm still learning (and have a lot to go!) but earlier in the process I blew up a cheap inverter. That was how I learned that VOC is different to the voltage under load.

slave1

When I was building my 32cell pack I made a real life sized template on a 2.4m length of wood, helped me get the BMS wires extended correctly and avoid accidently "mis-busbarring"