Battery Configuration on 1994 390 CPMY

[tonyiiiafl]

After working the bugs out last season, this season will see a new and improved battery bank. The stock bank is Batt 1- Starting/house, Batt 2- starting/house, Battery 3 genny.

I am going to try and get a set of 6V GC batteries set in place by using a group 24 starting battery for position 1 on the selector switch. I would use this battery exclusively for stating each of my thirsty big blocks. I will then remove the #2 battery and place the GC batteries in that space by turning them sideways. That will leave enough room for the dedicated Genny battery, and hopefully, more space for another set of 6V GC batteries. I will be replacing the charger with a ProMariner 1250P 50 Amp 3 bank charger. I will access battery 1 and the house (battery 2) by opening up the Master Battery Selector Switch and running lead one to the lug for battery 1 on the rear of the switch, and the same for lead 2, at the back of the switch. As for the Genny battery, I would also access that from the rear of its own selector ON/OFF switch. This leaves me with the single ground lead from the charger. Do I run the ground to a terminal block, and then run a lead to each negative terminal of each bank, OR could I just run the negative lead to either the port or starboard engine, which should, in theory close the battery circuits and charge fully. I will have 60 AMP MAXI fuses at each connection on the battery switch and also at the positive side of the genny battery. I wish to ensure that I can stay on the hook overnight, have plenty of juice to run the fridge and lights and an inverter for todays no energy using LED TV. So, I would start on position "A". run and warm engines, charge battery, then move selector switch on "B" for the rest of the day.

Thoughts welcomed, comments welcomed and also any ideas or things I may have missed??

[Viper]

Source of the post.....Do I run the ground to a terminal block, and then run a lead to each negative terminal of each bank, OR could I just run the negative lead to either the port or starboard engine....

As long as everything is grounded together, it doesn't really matter, just try to avoid hooking up to a battery, the fewer cables you have on them the better. Ensure that your generator's ground isn't isolated from the rest of the banks or it will not charge. Since some applications rely solely on the generator to charge its own battery it may not be grounded to everything else except the bonding system. This is not an acceptable charging circuit ground so you must have an appropriately sized battery cable connected to one of the other banks or an engine block or negative buss.

[Viper]

I've always preached on several threads that the best carefree set up is for each engine to have its own isolated start battery, then have a dedicated deep cycle house bank, all isolated from one another so that one system can't drain the other. No battery switch position to worry about except ON or OFF. The conversion isn't that difficult but it is more time consuming and more expensive because there are charging considerations to overcome that require additional hardware but it is the best setup for carefree boating, extending your battery life, and ensuring you're not stuck on the water with no battery power.

When you're under way on battery one, how are you charging the house bank (battery 2)? You could put the switch on ALL, but this combines both banks and creates other problems. The only way to avoid these is to maintain bank isolation.

[tonyiiiafl]

When I start the engines on battery 1 I warm up and run the first 1/2 hour on position 1 to recharge the start battery. Then I switch to 2 or house for the rest of the day. I never run in both except in an emergency when I need the power to start engines. Haven't ever had to yet.

[Viper]

Definitely not ideal. You have way too much to remember/think about while underway IMO. Do you switch while the engines are running? If so, are you sure you have a "make before break" switch?

[tonyiiiafl]

I do have a make or break switch and have been doing it this way for years and it is part of my post launch checklist.