Can the Generator Charge the Starting Battery?

Inspector

2012 Roadtrek Agile
We have a 2012 Roadtrek Agile with the LP genset. Is there any way to charge the engine starting battery as the van came from the factory?

Secondly, it would have been nice of Roadtrek to have mounted a exterior. 120v outlet to use without having to have the side door open, just a thought.
 

mikeme

2015 LTV IB: 2015 3500 V6
Drive it someplace.

or the lower 12 volt outlet might be connected all the time and let you back-feed a moderate charger inside the coach, powered from 12 volts dc, or 120 v ac.

(like five or ten amps or so. nothing that will charge a dead battery in a hurry.)

if you really want to have this capability, you have to add some equipment.
 

Inspector

2012 Roadtrek Agile
I was thinking if the starting battery went dead while away from home, the genset could give a nice boost through a built-in provision such as a charger or other means......wishful thinking.
 

BobLLL

Member
The generator should charge the starting battery in the same way shore power charges the starting battery. The generator provides AC to the converter-charger, which begins charging the coach battery. When the coach battery voltage rises over 13.4, the battery separator should "join" the two batteries, and both should continue to charge.
 

Inspector

2012 Roadtrek Agile
I have 2-6 volt batteries under the hood for the RV part and the underfloor starting battery. So the generator will change both with the starting battery being the priority?

Thanks
 

BobLLL

Member
We have the same batteries, generator, and converter. Yes, the LP-powered generator will charge all batteries, but the coach battery pair has priority. The generator feeds the 120v system, same as shore power does. The converter takes the 120v and puts out a 12v DC charging current. The converter is wired directly to the coach batteries under the hood. When the coach battery voltage is over 13.4 for a minute or so, the battery separator under the hood will connect the coach and starting batteries together.

So if your coach batteries are run down, their voltage will not get to 13.4 for several minutes. During that time the separator remains disengaged and the starting battery will not get any charge until coach batteries get mostly recharged and the voltage gets over 13.4. Usually takes only a few minutes.

Want to know if your starting battery is really getting charged? Stick one of these in the cigarette lighter outlet in the center console: INNOVA 3721 Battery and Charging System Monitor, about $20.

Snap 2019-04-24 at 17.45.12.jpg

innova voltmeter.jpg
 

Inspector

2012 Roadtrek Agile
BobLLL, it sounds like what I was hoping for is already setup with the converter and separator. I will just have to wait until the voltage rises to get the charge to the starting battery. I ordered the power socket voltage tester, it's really a compact meter that can be stored easily. Thanks!
 

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