"garlicman" None wrote in message
. ..
I've got a pedal powered generator using an old PM DC motor from a
treadmill. To charge my deep cycle battery, I'll need a diode to prevent
the
motor from spinning me backwards. How do I calculate the size that I
need?

The battery is 12V, and I'll rarely produce more than 120W of power. Do I
just call it a 10A diode? Larger is okay too, right?

Thanks.



If the diode has no heat dissipation then I would use the diode of the size
2X the load, otherwise 10a would work. (120W * 2) /12V = 20 amps.