Trojan Boat Forum

My port side starting battery doubles for the house battery. [1 battery for each engine, two for the generator]. Going on a two-week cruise in about three weeks. Lots of anchoring out. Thinking about adding an extra battery [obviously in parallel] to the port for added house capacity. [Probably don't really need to, because even if drained should still have three good batteries in the morning for starting... just don't trust the teenage crew to be conservative with electrical usage...]

Can I just add the battery, and expect a slower charge from the alternator [and battery charger...3 bank battery charger] or do I really need to screw around with a heavier duty alternator [and charger?] ...In which case I don't think I would bother with it. Thanks

Happy Memorial Day;

Thank you veterans for your sacrifices.

Why two batteries for the generator?
I would put the second generator battery in parallel with the port battery and then run the genny twice a day while out which should keep the batteries up.

I tend to run my genny in the a.m. for coffee, hot water etc: and then longer in the evening to charge and just supply AC for nightime activities, lighting, and anything I can run AC (Sat. radio). If your fridge is AC/DC I crank the temp up while genny is on and reduce to low when on the battery.

I also anchor for much longer than I run so don't worry about the Alternator situation... it does what it can do.

If you do anchor out often I would make the extra batteries dedicated house and run Stereo, frig and any other high draw of it only.
3 leg charger should handle that fine... house/port eng./star eng.
NOTE: many gennys charge their own batteries so it does not require charging by the charger.

Boat came with the genny wired that way...but great idea....why didn't I think of that...thanks

make sure thatthe dedicated genny battery does nothing else but start that genny.

That way if everything is dead, the genny will still start and then you can charge your batteries with the house 120v charger

RWS

Ditto to all comments so far. Dedicated genny battery, only one needed. The genny will keep it topped up if you use the genny throughout the season. Don't leave the genny on "AUTO" this circuit will draw off the battery.

Ultimately, each engine should have its own dedicated battery, and the house bank should be isolated from the engines. Use "ON-OFF" battery switches only, not the ones with "BOTH". Incorporate an emergency start solenoid (you may already have one) to parrallel 2 banks should one of the start batteries fail to crank an engine, and a battery isolater or combiner to charge all banks off the two engines but maintain isolation.

The amount of time your fridge comes on will really dictate how much power you'll go through. What really helps me is the addition of an exhaust fan in the fridge compartment. When AC is available (shore or genny) the fan comes on. This really gets heat away from the fridge cabinet and the condensor making it more efficient and helps keep cycling to a minimum. Also thinking of picking up a 12 volt computer fan and a small solar panel for this function.

Retrofit your anchor light to an LED, this will save energy, and it's not something you want extinguishing over night due to lack of power. It's also not good for the batteries to let them drop that low.

Have a great vacation.