I want to charge a bank of four 12V, 100Ah lead-acid batteries using a
56V, 5A transformer (so about 78V DC). My plan is to reproduce the charging stages provided by the UC3906 (but scaled up for 48V) by using PWM to control the voltage seen by the batteries. The logic is easy enough to implement in a microcontroller but I'm stuck trying to figure out what size to make the inductor (basically, the PWM controls a FET that turns the supply on and off with an inductor in series and a diode between the FET and the inductor allowing conduction from ground). Art of Electronics (2nd ed.) gives a single example but I'm afraid it's been a long while since I've done anything with inductors. Can anyone give me any hints?
Ken Muldrew firstname.lastname@example.org (remove all letters after y in the alphabet)