Exactly what Ivan said.

Part of your math is theoretically correct, however connecting two dissimilar batteries is series would have a few bad consequences. The first is that the lower current battery would not be able to pass the full current of the higher current battery. In fact, no battery will be able to pass more than its current rating. If you take two 100A 6V batteries and connect them in series, you get 12V@100A. Current stays the same, voltage doubles. In parallel, current doubles and voltage stays the same.

The formula you used is the one used for resistors......

If you connected two dissimilar batteries in series, the smaller one would cook. Charging them would be an equally dangerous proposition.

Cliffmac sez: "keep this in mind as well, amperage and voltage are input measurements, watts are a measure of output...2 different things...."

Not quite.... Watts are a measure of power (the symbol for watts is P), which requires you to know two things in order to calculate. Knowing any two of the following variables allows you to calculate Watts. They are: Voltage, Current, Resistance of circuit. Also, Watts are equally applicable to input and output. It's just a power measurement and can be applied to any current.



-tp