I've read that the most typical approach to charging, is to provide as much current as you'd like (lower current causing less loss of capacity over time), and to stop when the cell reaches 3.6V. The cell should then come to a resting voltage around 3.3V.
My problem is that my car alternator may only be able to provide 13.6V, or even less.
If I charge a cell at 3.4V, or 3.3V for that matter, obviously the charge current won't be as high, which is acceptable. But how do I know when to stop charging?
One guy did some tests and charged to different voltages, and stopped only after leaving the current was down to 30mA (C/100), and found that charging at 3.4V was still able to charge until 99% of capacity.
But is C/100 the correct current level to stop at?