[ljracer]

I'm seeing the Nov 28 date on Amazon shippers too.. GB 1PC price is 4.24 for unprotected and the 4pc price is 5.60 each... Ordering 4x1 is cheaper....

I would order a bunch today if I knew they would ship; even waiting...

 

[bianchifan]

Nice & cheap BMS - 7A max.

Found in Novemberstart, ordered on world's selling day 11.11 for about 12 bucks:

5pcs 2S Protection Board w/Balancer, 7A max

Arrived yesterday, not tested yet still waiting for 4cell BP from Deals??.

 

[ledoman]

Good find. Looking forward for test results. Can you make more detailed picture of one PCM so all elements could be clearly seen.

 

[bianchifan]

Can you make more detailed picture of one PCM so all elements could be clearly seen

I's shure all elements are visible..nevertheless here we go

It seems forum's UL doesn't show the whole size


OK..there's something weired with the forum's SW..it's sqeezin' my pics and blowin' my thumbs

 

[ledoman]

Great, thanks. Will ask Archie to look the circuit and tell his opinion.

 

[bianchifan]

Q1/2 are AO MosFets, U2/3 3.2V refs with "auto discharge func".
U2 I couldn't identify.
PDFs can't be attached due to exeeding size

 

[tigris99]

I'll stick with adding balance leads and using my balance charger . Auto discharging some cells to balance out others.... Not sure I like that, but ill wait for Archie to chime in.

 

[ledoman]

Discharging is what the hobby chargers do to balance cells in series so this method is nothing unusual.

 

[-Archie-]

The board looks quite normal IMHO. As for U2 chip - it's a protection controller, most likely clone of Seiko S-8252, according to pins #1 and #2 connected to the gates of charge/discharge FETs...

 

[ledoman]

Thanks Archie. I might get one and maybe direct Kaidomain to try them out on their new packs. Do you think it is worth using it. From specifications on Ali web page it has parasitic drain of "Single use batteries (consumable) :4ua or less".

 

[-Archie-]

I don't trust Chinese descriptions found on the webshops unless I've verified/measured everything myself.

Maybe in some limited applications this board is handy, if the battery will be glued and not accessible for ordinary balancing routine. I'd prefer not to add any additional circuits beyond standard protection PCB and safety fuse, but YMMV...

 

[bianchifan]

As for U2 chip - it's a protection controller, most likely clone of Seiko S-8252...

That was clear IMHO.
But I miss my crystal ball for determing the exact switching points.