Existing Battery Charging System

Heyo! So we’re a couple weeks from completion and it’s time I face the electrical system I’ve been avoiding. What we have is a 2011 E450 Starcraft 19 person shuttle. It already has an accessory battery (STD) mounted on a sliding tray that pulls juice from the motor of the shuttle; I wanted to locate our AGM batteries here but I’m not sure if the existing charging system is suitable for AGM batteries? Does anyone have experience with these Starcraft versions of the E450 electrical systems?

AGM batteries like to see charging voltage between 14.4 and 14.8 volts, and once charged they like to be float charged between13.6 and 13.8 volts. Nothing more, and a charging rate less than 20% of its capacity - preferably less. If you charge with 15 volts or more it will off-gas the battery and you’ll very soon have nothing more than a boat anchor.

A smart charger with a temperature sensor is the best way to go. At high temperature (summer daytime) the battery likes to see even lower voltages. I charge mine using a solar panel through a charge controller that’s specifically designed for AGM type batteries.

For your application, check the charging voltage at the house battery terminals. If it’s between 14.3 and 14.8 or so (no higher) then you’ll probably be okay.

With your setup - house battery outside the living area, I think you should seriously consider flooded deep cycle batteries instead of AGM. They’re less expensive and more tolerant to bad charging. You’ll just have to monitor the acid levels, and top off with distilled/deionized water as needed.

Thanks for the reply. So at worst case scenario, I’d be looking at installing a smart charger between the battery isolator and house battery?
(is AGM the way to go?)

I just edited my post to say that you should probably use flooded deep cycle batteries since it’s outside the living area of the van.

Yes, I kinda thought there’d be a better suited batt. type for that location. It’s just so convenient and simple! The tray will hold up to 2 more batteries for a total of 3 so capacity wont be a problem. I’ll start with testing the voltage and go from there. Thanks!

You’re welcome. Good luck.