Never even gave this a thought. Here is how I deal with this, although I am on a power boat
, with two engines, so it is a little more complicated, if on a single engine
, just use half of this.
The company I work
for makes an all electric
APU for trucks, so I'm exposed to DC power quite a bit. I purchased two battery
separators, and put them between each starting battery, and my house battery bank. A battery separator monitors voltage on both 'legs', or both battery 'banks' it is connected to. When it 'see' 13.2 VDC at one leg, it closes, and allows this charging
voltage to flow to the other bank as well, so both banks get charged. Now, on a semi-tractor, if the starting battery drops to 12.8 VDC, the separator opens up, because starting takes precedence over anything else, as it should on a boat
But because I have two 5.7 liter engines, with only 55 amp alternators, I cannot, and do not want just either one (just one 55 amp) alternator
to try & charge what would end up being 5 batteries
(4 house batteries, plus a starter battery). So, I have a special heavy duty relay that has two special posts. I use this relay to separate the house battery bank into two banks of two. When the engines are off, one post receives power, keeping the relay closed, so I have a completed 4 battery house battery bank, and my four inverters (one for the refrigerator
& outlets throughout the boat, one for the microwave, and one for each AC system).
I purchased this 1982 Trojan Tri-Cabin this past March, with super low hours on the engines, and only 94 hours on the 6.5 KW Onan Gen set. I'm taking the Gen Set out this winter and selling it, and replacing it with another 4-8 AGM
batteries. Today's cruisers don't want the noise
use of a generator
, and inverters have become so efficient. And between solar
, and I'm considering toying with a water current generator
, if you aren't going anywhere for a longer period of time, you have the ability to recharge you batteries. Silent, or near silent energy is the future.