8D Batteries

[VolNavy91]

Last post got side tracked on the generator issue but still need to get new batteries. Need two 8D's for my 400 with twin Cummins 6BTAs. Set up has them acting as house and starting batteries. Running the stock Pro Mariner 30 charger. Would like to go maintenance free since I can't reach the back battery to service it easily. Thanks in advance.

[nightsky]

We have a '94 390, basically an identical boat to yours, with minor interior layout changes. Engines are the same, as will be the the engine room layout. My recommendation to you, while you are replacing the 8D's, is to have separate house and start banks. That way, you can prevent getting in a situation where the house bank inadvertently runs down so low that you can't start your engines. Being able to start your engines should be top priority and should have a separate battery. You could still install a MBSS to combine the 2 banks if the need arose. Having said that, a single 4 D battery (much lighter than an 8D), will start all 3 of your engines and still have extra cranking reserve. As to the house bank, deep cycle batteries are best suited for this. Typically, 6v golf cart batteries provide the most Amp Hour punch. On my boat, I have the 4D, and 6 golf cart batteries, all in between the engine stringers, covered by the floor boards. Removing the floor boards provides easy access for watering. One advantage to these batteries is that they are much lighter and easier to move around than those beastly 8D's.