Lead acid batteries are not set up for continuous current charging, although they will tolerate a low current... how low? Don't know, because their makers specify a charge VOLTAGE, not current. That's why you need a constant voltage (current limited) charger. In systems where you want fast recovery of battery charge (like a car) the typical set voltage for the charger is 14V. For float charge where you just want to maintain charge long term, use a lower voltage. I run about 13.2V on mine.Just out of interest, is the "at least 5A" strictly necessary for some reason, or will it just ensure that the battery is charged to a reasonable level before the natural end of your life?
I was told before that 1/10 of the battery's capacity is usually a suitable current to trickle-charge at (though that may specifically apply to NiMH batteries, which is what I was using, I don't know), but that the current could be reduced, it'd just cause slower charging.
Is there a minimum current for charging a car battery? Other than the leakage current of the battery of course
Some kind of current limit is needed to make sure the battery doesn't get cooked while charging. I suppose s eries resistor is a brute force way, I usually build the current limiting in.What about an upper current limit for charging? Should a resistor be used in series to prevent too much current with a car battery?
Just out of interest, is the "at least 5A" strictly necessary for some reason, or will it just ensure that the battery is charged to a reasonable level before the natural end of your life?