Recommendations welcomed: I’m slowly...

[uncharted_water]

Recommendations welcomed:

I’m slowly working on the wiring in my 1980 300EC. There were three (3) size 31 batteries in the engine compartment that I recently replaced (not hooked up yet though) and a single (1) 4d battery located under the helm foot rest. The owners manual I have doesn’t show the number of batteries on the wiring diagram (which I’m working to create my own anyway), and it certainly doesn’t show any other location for the batteries other than in the engine compartment. So, my guess is that the 4d battery, which appears to only be wired to the charger and stereo, is solely used for that system. The three (3) size 31s can run everything in the boat otherwise. I also have the original generator.

One thing that I’d like to know from other owners is what charger and/or charger/inverter they run? The TrueCharge 40+ AMP I have I’m assuming is toast given the corrosion and scorched wiring insulation on the leads in/out. All systems appear to be original (engines, generator, fridge, electric stove top, outlets, ac, etc).

[wingless]

That additional 4D battery is possibly a good choice for usage as a house battery, to extend run time for stuff like the 'fridge.

My suggestion is for everything to meet / exceed ABYC and to start w/ a wiring diagram.

The battery charger should be appropriate for the installed batteries. It is typical for three banks on a boat w/ a generator, house / helm / gen, w/ port and starboard to each be connected to house or helm.

AGM batteries are good and they prefer lots of charging current. Flooded cell have lower specified charging current. All chargers will run max during bulk, then throttle back during absorption phase. A larger charger will hit absorption slightly sooner, probably minutes sooner. A good seat-of-pants is 10A, minimum per battery, more is better.

Always use marine wiring and connectors attached w/ a quality / appropriate crimp tool.

Per ABYC, wires must be secured and protected throughout the run. My preference is the ABYC color code. My preference is to select wire gauge at least one size thicker than required per the table.