I recently salvaged this small (30 x 9.5 x 3.5 mm) LiPo single cell battery from an old device that lied broken for at least 3 years.
Therefore I expected it to be garbage ready for recycling, but when I measured its voltage it read 2.8V, so it seems to be in good shape. Hence I decided to keep it in my junk bin for experimentation purposes.
The problem is that I couldn't find any datasheet or info on the Internet, so estimating its capacity is a problem. In particular, I'm well aware of the LiPo charging technique that requires a constant-current phase followed by a constant-voltage phase, as this TI application notes explains. Excerpts:
At present, the major Li-Ion cell manufacturer recommends 4.200 +/- 50 mV as the ideal set point voltage, and 1c (a charging current rate equal to the A-hr rating of the cell) as the maximum charging current that can be used.
Since I never played a lot with LiPo batteries, I'm clueless at guessing its capacity (for what I know it could be anything between 100mAh and a couple of Ah).
Can anyone suggest me, if possible, a reasonable and safe estimate for its capacity or C rating, so that I won't be risking to overcharge it in the CC phase?
EDIT (to incorporate some more info, as prompted by comments)
the cell weighs approximately 1g (something between 1g and 2g)
it was embedded in an old (6-7 years) Bluetooth receiver for indoor usage (one of those small boxes that can be connected to the headphone jack of an amplifier to send the PC audio to your Hi-Fi system or whatever)
as far as can be seen by close visual examination, it doesn't embed any protection circuitry