A necropost, and a weird one. What extension cord? Do you know what an inverter
The follow up to all of this, for those who are interested, after 70-odd days at sea this year.
Following advice here I combined the two battery
banks. Besides that, I discovered that one of them consisted of old batteries. I replaced these (4 batteries).
The results were wonderful. I used a combiner switch so I could uncombine the banks as necessary but eventually just started leaving them combined. I get a full 24 hours of normal life on board on the hook out of this battery
bank without a deep discharge. The instruments are not bothered by the bow thruster, although the cabin
lights do dim somewhat when that big boy is churning out 10 horsepower of side thrust.
So I no longer feel the need for a much bigger charger
; the Newmar and the 110 amp alternator
on the main engine
are keeping up fine with the power needs on board.
I will eventually install a Victron charger/inverter but there is no pressing need now. Oddly enough the function of this unit which I most need is the function which supplements shore power
with battery power when the shore power
connection is overloaded. I installed a Victron isolation transformer that is very strictly limited to 16 amps, and I am constantly tripping the circuit breaker when I'm on shore power.
The inverter will cut down on short generator
runs used for things like toasters and microwave. The heavier duty charger
will just be a bonus.