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I picked up a bunch of Chinese-made 2S BMS / Balance boards. As is the norm with inexpensive Chinese boards, they came with essentially NO documentation aside from how to hook the board to the batteries and load.

I've identified all of the devices on the board except for the chip that controls the BMS function. This is a SOT23-6 with the letters "PAYG" on top.

I'm hoping that someone can identify this chip and point me towards a datasheet for same.

enter image description here Full Board

Dwayne Reid
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  • Is this bms working for you as expected? I am connecting two 18650 batteries to appropriate ports, can measure 4.1v and 8.2v on appropriate panel terminals, but the output just 4.64v. I can measure 3.1v between battery 0v terminal and the negative output terminal and 8.2v between battery 0v and the positive output terminal... – cly Nov 13 '21 at 16:18
  • I have used only a few of these so far. They appear to work as promised. – Dwayne Reid Nov 14 '21 at 18:11
  • I connected it to a charger device with 8.4v output. After few seconds I disconnected the charger and measured again. The output port became 8.2v. So it looks only the initial state was "bad". Good to know. Thx – cly Nov 15 '21 at 10:36

1 Answers1

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PAY is Seiko S-8242AAY-M6T2GZ battery protection IC. The last letter G is related to lot number.

Here is PDF (see table on page 23 for part code): http://img.hqew.com/file/Others/1090000-1099999/1098111/Electronic/201251816354378771.pdf

And there is the list of codes, which contains PAY: http://www.dl7avf.info/charts/smdcode/cpa.html#TOC

VillageTech
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