I am wondering about the output of batteries wired in series.
If I have say 4 batteries in series each being 3 volts and 500mAh, Will
the
output be 12 volts at 500mAH or 12 volts at 2000mAh?
Thanks--
Anthony B

Batteries in series will add the voltage and the current rating (mAh) will
stay the same. You will have 12 volts at 500 mAh in your example. If put
in parallel (not always recommended) the voltage will stay the same and the
current will add. Given the same bateries you get 3 volts and 2000 mAh.