Can I connect batteries of different ampere hours in series?
$begingroup$ Read my answer carefully, especially the last 2 lines. Same type, model and capacitance. When placing batteries in parallel always make sure they''re the same voltage. One SLA at 12 V and another at 11 V will cause VERY LARGE CURRENTS to flow as one charges the other. First connect them with a resistor or a car lightbulb in between to …