Quote:
Originally Posted by akin_alan
I have a Tohatsu 9.8 outboard on my 30' 1974 Grampian sloop that I bought a few months ago. Very much enjoying the boat. My understanding is that the outboard charges the battery with 7 amps DC power.
I read the specs on Yamaha and Honda Generators. They put out a whopping 1000 Watts AC power! Well AC is something that I don't use much on my boat. DC is what I need. They only generate 7-8 amps DC power. 8amps x 12 volts = 96 watts DC.... I think that ain't much. I got three 90 (+-) amp batteries. Does that mean I got to run this generator for nearly 30 hours just to charge the batteries?
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I'm a bit confused with the power conversion. A Honda 1000W generator puts out 1000W at 120V AC. 1W = 1A X 1V, so in this case:
1000W = ~8A X 120V
If you replace that 120V with 12V and keep the wattage the same, don't you get:
1000W = ~80A X 12V
The power output is the wattage, and it should remain constant, shouldn't it? If you lower the voltage, doesn't the amperage increase? Or is this one of those AC/DC things?