dodgey Cell in new Headway 16s 38120?

[Kabbage]

Hi - I have just finished building a new battery using 16S Headway 38120 flat-tab cells for my first build commuter https://endless-sphere.com/forums/viewtopic.php?f=6&t=39940.

Bought the Cells from EVAssemble (http://www.evassemble.com/index.php?main_page=product_info&cPath=2&products_id=19), along with one of their bleeding balancing BMS (http://www.evassemble.com/index.php?main_page=product_info&cPath=6&products_id=211).

On my first test ride - I got about 15 minutes in and lost power - I suspected the BMS shut things down.

So I charged up and tried again - went fine for about 15 minutes and then stopped again.

Checked the individual cell voltages at the BMS connections. Hot off the charger, they were all 3.36V - Except Cell 11 which was 3.28V. Oh-ohh.

After the ride, when it had shut down, they were all 3.31V, except cell 11 which was 2.48V (I guess it's lagging under load to the 2.1V discharge protection voltage of the BMS??)

So, now what do I do? - do I have any choice but to pull the battery apart and replace cell 11 with a new one? Is there any way to resurrect it? What a palarver!

Any help appreciated!

Cheers = Kabbage

 

[amberwolf]

When you first got the cells, were they balanced or in their present state?

If the latter, did you try ensuring they were all charged to the same state before assembling the pack?

If not, you should try that first.

If you do not have a single-cell charger or other way to bring up one low cell at a time, then you can simply leave the charger hooked up until the BMS eventually balances the pack (which could take hours, days or weeks depending on how badly out of balance the cell is, and how much current the BMS can balance out at a time).

 

[Kabbage]

Thanks Amberwolf - I sort of checked them, and they seemed ok. Perhaps I should have checked them better - live and learn I guess.

I do not have a single cell charger - so that's going to be difficult.

I have left it on charge for a while now, several days at least, and I'm not convinced that the charger/BMS is capable of getting this one back. I think the charger decides to turn itself off after a while, and won't begin 'topping up' again to keep doing the bad cell.

It's going to be a hell of a job to pull that one cell out of the pack, but I don't see any other option at this time. Is it possible that the cell is just bad - and that it would be better in the long run (for the sake of a $20 cell in a $200 pack) that I should just replace it and be done with it? (depending on how hard it is to get one of these cells in Australia! It was a real issue getting them from HK from EVAssemble due to the Lithium battery transport restrictions...)

Is there some 'hack' I can use to charge just this one cell while it is still in the pack? And what would I use to charge it, considering all I've got is a dedicated 16S charger?

cheers - kabbage

 

[999zip999]

New battery I would sit and watch while I have a single cell charger on that one cell do you have access to the negative and positive end ?

 

[999zip999]

Never charge over 3.65 volt Never. Never. G opp uSit there right there and watch it. Sit there.
Please don't walk away and piss at 3.45 volts. That's alll most alll full. 3.6 volts is a srcond away. Get it.

 

[999zip999]

Wow trans bass sound sound breakdown. Wow worth wow words the time. Sad third time printed third time. This has been done for 25 minutes text to Todd or text to talk
Hello disease allies of this paragraph to me 25 minutes

 

[999zip999]

Yo

 

[999zip999]

Bugs.

 

[999zip999]

Wolf Administration you mean invaded