Generator vs Battery/Inverter/Solar
We have just purchased our first truck camper - a used 2007 Lance 845 and have a couple questions that I hope you can help us out with. The camper is still at the dealer and we're considering having a...
Forum Discussion
ticki2 wrote:
I didn't like the idea of continually pumping 14+v into a fully charged deep cycle battery which is what happens when the solenoid feed is connected to an ignition-on feed. Comments ?
Flooded lead acid batteries will take this without much problem, though it will eventually boil the water out. But that is what is happening to your start battery anyway. AGM batteries are more sensitive, they will take it but it will shorten their life. It will kill gel batteries quickly. There are products made to solve this issue. One is this Balmar product which solves a few problems at once (at a cost). Properly connected, this provides isolation, switching, high current protection, and proper 3 stage charging for the house battery. It limits charge current to about 30 amps, regulates the charging voltages to those appropriate for the battery chemistry (regardless of what is under the truck hood), and can be switched off to isolate the two sides. On my installation, I took the charge wire from the 7 pin and connected it to the control to turn it on. That works on a Ford since the 7 pin charge wire is switched by the ignition. I set the charge parameters in the Duo Charge to the AGM setting for my AGM house batteries.
Compared to a simple large cable and relay, there will be some increase in charge time because the initial charge is limited to 30 amps vs. maybe 60 or more for a short while. It doesn't take very long for the acceptance rate of the batteries to fall to 30 amps though, so the difference isn't all that great.
Is this overkill? Maybe, lots of people just cable the AGMs and don't worry about it. I learned this stuff wiring yachts in which the 12V DC system is much more complex, and much more important to survival, you want to get it right.
