"Thomas Wentworth" wrote in message
news:dz7Df.1473$UY3.1361@trndny05...
I get so confused when it comes to electric power, especially
battery output. How many AMPs can a battery put out before the
battery is dead? Say, a 12 volt battery. Could you put this as
.. "if you have on a light for xxx hours the battery is gone".

I know AMPs are the flow of power and volts is the possible
amount .. measure of flow and time . and light bulb.

Why am I asking? I was looking at this boat on a web site and
the owner had added a bank of small batteries. About half the
size of the marine ones I'm use to. The batteries were tied
together so they became on big battery in power possibility.

Now,, if he had 6 batteries and each one is an 8 volt .. does
this mean he has 8x6 = 48 volts of possible power? And how does
this work out to amps. ?

1. Volts = pressure. Add batteries nose to tail (+ to -, or in
series) and you add up their voltage. The most common sipboard
voltage for yachts 20ft to 40ft is 12v (actually, 10.5v to 12.7v,
depending on their charge state).

2. Battery capacity is shown in ampere x hours (AH). Very
approximately, divide the AH by the number of amps you're using,
and that's how many hours you'll get out of the battery if it's
fully charged.

3. If you join similar voltage batteries nose to nose, and tail
to tail (in parallel), the voltage will stay the same, but the
capacity will multiply by the number of batteries.

4. If you re-charge your discharged 12v battery using a 48watt
(power: watts = volts x amps) solar panel, you should get 4 amps
out of it (48/12), and if it keeps up its 4a (which it won't)
you'll get 4 x (the number of hours) of AH back into the battery.

Those are the basic rules. They get screwed up by efficiency (or
lack of it), but they're a good start.

Have fun doing the sums.

JimB
http://www.jimbaerselman.f2s.com/sw_peloponese.htm