Li-Ion cells are nominally at 3.6V per cell and are typically charged to
either 4.1V or 4.2V depending on the manufacturer and your needs.  Yes,
the SO8 is indeed a battery superviser meant to stop any discharging
when the cell drops to around 3V among other things.  And by the looks
of it, the chip was made about the end of June 1999 (9926 = 26th week of
1999).  I would suspect that the battery itself was close to the same
age and is probally of little value due to the fact that  Li-Ion has a
typical life span of about 2-3 years and ages even without use.  The 6
pin IC is a Motorola part and is the power switch that disconnects the
battery when the voltage drops below 3V.

Charge rate on smaller Li-Ion batteries such as cell phone batteries can
be done at a 1C charge but would be better at about one third of that.

Josh Koffman wrote:

>Hi all. I picked up two cheap cell phone batteries today (for an
>Audiovox 3100), with the idea that I'll use them to power a new
>project. Lithium Ion batteries for $3, I love surplus!
>
>However, now I have to charge them. Here I have problems, as I know
>LiON cells can be picky. I popped one of the cases open to take a
>look. Inside is small PCB with two chips, which I'm guessing are the
>battery supervisors. However, I can't seem to find anything about them
>with google. The larger one (an SO8) is marked like this:
>9926
>("S" logo with possibly arrowheads at the tips or a line through it)
>BM (triangle symbol)
>(small circle) W06C
>
>The second chip, a six pin affair (possibly 6 pin SO23?) is marked like this:
>MBOR
>(dot) (M logo, most closely like this: .\\, except the . is a small line)
>
>Any help identifying these would be appreciated. I will try to get a picture.
>
>I've also been looking at some charging chips from Maxim, but I'm
>honestly not sure how many "cells" I have. It's a 3.6V 1100mAh pack,
>and on the inside is the little circuit board, and a flat rectangular
>pack about 1"7/8 x 1"3/8 x 5/16". It seems to be one solid piece, not
>smaller cells heatshrunk together. Is that considered one cell?
>
>Thanks!
>Josh
>--
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>fools.
>        -Douglas Adams
>
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