Resolved (Ecoworthy Replaced all 4 of the batteries)

[Boron]

Does anyone know if you can actually buy pouch Lifepo cells as a private buyer? or have you got an MOQ of 1000+
AFAIK the view is that these are "potentially - at this moment" a better bet than cylindrical or prismatic cells because of the easy of rewrapping used cells and selling them off as fake new ones - grade A is something misleading as this is a term only used by the EV industry in partnership with the PRC.

It seems that pouch cells are used in EVs and are a supposed to be a robust technology and they dont lend themselves to the re-wrapping scams just yet (of course RC and drone guys YMMV)

There are some YT vids showing tear downs of these - eg Ecoworthy - that needs a separate topic.

 

[BarracudaBob]

Does anyone know if you can actually buy pouch Lifepo cells as a private buyer? or have you got an MOQ of 1000+
AFAIK the view is that these are "potentially - at this moment" a better bet than cylindrical or prismatic cells because of the easy of rewrapping used cells and selling them off as fake new ones - grade A is something misleading as this is a term only used by the EV industry in partnership with the PRC.

It seems that pouch cells are used in EVs and are a supposed to be a robust technology and they dont lend themselves to the re-wrapping scams just yet (of course RC and drone guys YMMV)

There are some YT vids showing tear downs of these - eg Ecoworthy - that needs a separate topic.

The 100ah 12V Eco-Worthy has a YT teardown with prismatic cells. I just cut 4 of mine open and they were all pouch cells. Zero issues but I wanted to put them on a 16S BMS instead of 4 in series. I didn't tear into the pouch cell cluster because I plan on using them. Quick search found on Alibaba and aliExpress but you need a PCB or something to interface to them.

 

[Boron]

. Quick search found on Alibaba and aliExpress but you need a PCB or something to interface to them.

Now I have seen something like that in my tears down see pic YKNY-CON61B-20230530 seems to have a scattering of little resistors across the board? maybe something to do with the passive balancer?

 

[BarracudaBob]

Now I have seen something like that in my tears down see pic YKNY-CON61B-20230530 seems to have a scattering of little resistors across the board?

The BMS has the resistors for passive balance. May be a slow self-discharge or a bunch of resistors from ground to each cell to B+ to stabilize each cell so it isn't a capacitance reading instead of a true reading. I used to use zero-ohm resistors to jump traces or act like a fuse link. Looks like we have a battery internals revile party going on (oh my)

 

[JoeHam]

I would email them. And let us know what they say

There has been no response at all

 

[Boron]

The BMS has the resistors for passive balance. May be a slow self-discharge or a bunch of resistors from ground to each cell to B+ to stabilize each cell so it isn't a capacitance reading instead of a true reading. I used to use zero-ohm resistors to jump traces or act like a fuse link. Looks like we have a battery internals revile party going on (oh my)

Scraped at the silicon putty careful not to trash the micro components that may be on the board, only to not discover any actual components installed at all on the board. I presume that the bare board was used as a convenient way to connect up the pouches. They are so tightly confined within the case I dont see any way to dissemble them other than slicing the case apart which seems a very perilous proposition at this stage. I will rather pursue attaching the JK BMS and hope it provides useful service. If that works then at least I will have obtained a means to obtain a source of genuine Lifepo cells
FWIW my chg/dischg on the other cell using the ZKE kit has shown a capacity of ca 30.5AH down to 11.00V - a good result.
Seems too good to be true given all the scam Cheap Charlie rubbish amongst the cylindrical/prismatic market. Reminds me of the era a few years back of humungous NiMH fake AA Eneloop cells - huge global embarrassment for Panasonic at the time

 

[Boron]

Someone posted this link recently but I lost the thread https://lynxpower.co.uk/product-tag/eve-lf280k/ They promise auto grade A cells
It was on my rant about not being able to get a reliable source of Lifepo cells in UK. I already contacted Fogstar - who have a big Web site grand standing their "uk based" manufacturing base (till I asked for photo evidence of their assy line). Well that went down like a lead balloon. Also they wouldnt come clean about what BMS they were using - given that this is a major concern for users faced with a black box. They stopped speaking to me but YMMV
See https://uk.trustpilot.com/review/fogstar.co.uk?stars=1 and be careful if you are a private customer its seems according to 7% glaring 1 star reviews. maybe they only want wholesale customers
This is the problem with black box gear - hence my push for DIY (if I can get reliable pouches

 

[wpns]

Now I have seen something like that in my tears down see pic YKNY-CON61B-20230530 seems to have a scattering of little resistors across the board? maybe something to do with the passive balancer?

View attachment 246718

Looks like most of those are unpopulated?

 

[astralography]

Prius Hybrid NiMH in steel - supposed to be a bomb proof chemistry. Can you say what caused the fire? External wiring fault?

Quite right a common mistake, thread some heat shrink on all of them

Something shorted out inside the battery. The wires coming out of the battery were all melted. The cabin filled with grey smoke, and I pulled over and got out of the car immediately. Drove the car for years before that happened. It was all good until it wasn't.

 

[rogerheflin]

Even if the batteries themselves don't have thermal run-away, shorting out some piece of a multi-kwh battery pack WILL heat-up/burn/plasma-cutter/weld any number of materials and even if said material should not burn until the power runs out.

It is making me like the idea of building a battery box out of flame-retardant 2x(4/6)'s simply because then most of the material of the box (that a wire could come in contact with) will not conduct and reduce the risks of shorts. I think I have sorted out how to build a rolling battery box (for 16x304ah) that is compact and under $100 for the rolling box itself and flame resistant and non-conductive.