Originally Posted by davido_
I have a Rockwood Premier 2516G (2015 model year). The instruction manual that came with the built-in converter seems to indicate maximum DC output of 30A. Is this the effective maximum charge rate as well (assuming no other draws)?
I ask because I'm trying to understand whether my time running a generator to recharge the battery will be minimized by using the built in converter with shore power cord, or by bringing along and using a 20A dedicated portable charger.
Maximum charge rate is only useful when in "bulk charge" mode, and then the maximum charge rate (amps) is related to battery size. If you have a single size 24 battery (85 amp-hours), the maximum desirable bulk charge rate is somewhere around 21 amps (25% of capacity). But bulk charge mode only applies to when the battery is at 50% to 80% of charge. After that, a 3 stage converter/charger switches to a different mode (reduced charge) to avoid overheating and/or boiling the battery. Charge rate tapers down to nothing as charge approaches 100%.
You don't want to run your battery down below 50% charge. Running it down further really reduces its lifespan. So the time difference in recharging a small battery (120 AH or less) at a 30 amp or 20 amp rate from 50% to 80% is literally a matter of a few minutes. The 80% to 100% charge time is not affected by the current rating, but it will be affected by the fixed voltage of the charger in this mode. A higher voltage will charge slightly faster, but at more risk to the battery.
Because it makes so little difference, why carry a separate charger? Just plug the generator into the trailer and let the converter do the work while you enjoy the AC (your converter draws about 400 watts while in bulk charge mode (much less in other modes), leaving the remaining generator capacity for AC loads).
my thoughts, your choices