We’ve checked off everything on our Prepare to Cruise checklist (hand over head systems, underways/landings, anchoring, mooring balls, locks, long day cruises, meal prep, and tender ops) with the exception of overnighting on the hook. Because I use a CPAP, and because I want a ready ‘clean’ source of AC power while underway (without the need to fire up the generator), I want to install an pure sine wave inverter (2KW-2.5KW). Stove/Convection-Microwave and AC would be generator loads, but I want all the ‘hotel’ services (network, laptop, printer, tablet/phone chargers, handheld radio chargers) to have ready power.
Here is the current DC power set up on our 1999 Maxum 4100 SCA as shown in the boat’s owner’s manual supplement. All batteries are Deka 8A8D 1450CCA 245AH@20hr AGM2.
Here is the inverter wiring, also from the supplement. I’ll take this as the manufacturer's desired wiring for when an inverter is added. The inverter battery I’d add will be identical to the other three.
We have a ProMariner brand ProTech 1240i Plus charger wired in the two bank configuration as shown in the charger’s owner’s manual and installation guide with the ‘spare’ third bank being jumpered to the second bank lug.
While I haven’t been able to completely hand over hand the DC output from the charger (the wires disappear into areas I can’t easily access) to verify the configuration, I’m assuming one bank goes to the single port engine/generator battery and one goes to the starboard engine battery and the house battery which are wired in series as shown in the DC wiring diagram.
Right now, unless I hear from folks who have a better way to do it, I’m planning on going with the supplement’s wiring. The one thing that doesn’t seem to make sense to me is why the inverter battery seems to be on the stbd engine/house side of things with its positive wire on the same lug on the battery isolator and the negative wire going to the house battery. Seems, at least to me, to be better to spread the love out and hook on the port engine/generator side. I’m only guessing here, but could it just be the simple fact the wiring would be shorter going that way then to add a foot or so to the positive side to reach the other side of the isolator and maybe two more feet to get the negative over to the port/gen battery? I’m assuming the battery isolator balances out the loads no matter what.