Breaker Size?

[wsvoboda]

I have a Honda EU2000 20 amp generator. My battery charger is a true charge 20+, the charger has it's own blue sea system breaker on the AC panel that is a 15 amp breaker. I use the blue AGM optima battery banks 4 in the house bank and 2 for the engine. My question is should I have a 20 amp breaker for my battery charger circuit? It seems when I'm at anchor and run my generator it never completely fully charges my bateries. The 30 amp dock power seems to charge them very quickly, I use a west marine ac power cord, marine grade 8 for my charger. Thanks

[donradcliffe]

Don't confuse DC amps with AC amps. The truecharge 20+ puts out 20 amps at 14v, but takes a maximum of 6 amps at 120v. A 15 amp breaker is more than sufficient for the charger. You have about 300 ah of battery banks, which will take some time to charge at 20amps

[GordMay]

Originally Posted by donradcliffe

... You have about 300 ah of battery banks, which will take some time to charge at 20amps

And even longer, if you try charging directly from the Generator's (8A) DC output.

As noted, current is inversely proportion to voltage, so a Output of 20A @ 12VDC nominal is roughly equivalent an Input of about 2 Amps @ 120VAC (+ some inefficiencies); for which the 15A breaker is actually oversized (no problem).

Power your Charger with the Honda EU200's AC Output, not the DC Output; because the DC Output is only 8 Amp (12VDC).