I'm currently setting up a backup system whose output should be a constant 12v 1A. I plan to use several good 18560's I salvaged from a laptop battery and connect them in series-parallel to get the required voltage. Now I need to design a charger for this 12V pack. All the design I found online usually deal with one or two cells. For this I'd have to connect several of them in series-parallel to get the required voltage and amperage. Is there any circuit for such a voltage level and capacity ?
I could include a uC in there for sense and control and stuff but I'd prefer to keep the circuit as micro free as possible. Any inputs ? Thanks.
A Lithium-ion battery cell is 3.2V when it is almost dead and its load should be disconnected and is 4.20V when fully charged. Then its average discharging voltage is 3.7V. Three in series make 9.6V to 12.6V which is not a constant 12.0V. You could use a 12V voltage regulator and four battery cells in series.
The Ah rating is not its maximum current, it is how much current it can supply in an hour. It can probably supply 10 times or 30 times its Ah current for a short time.
You need a circuit that senses low voltage and disconnects the battery from the load. Then you need a "balanced 4-lithium cells charger" for the cells.