My converter, Progressive Dynamics PD9130V Inteli-Power, only charges the two 6v lead acid, deep cycle house batteries. I wish it would charge both the house and chassis batteries. Are there any negative issues connecting a 3-amp Battery Tender to a 110v outlet on the RV to keep the chassis battery charged while the RV is connected to shore power? —Pablo, 2002 Fleetwood Bounder 31W
I do not know of any RV chassis manufacturer that would recommend or allow a charge coming from a campground source through the converter to charge your engine battery. First, you have the electrical surges from a campground pedestal that can wipe out most of the electronics in an RV, not to mention the engine alternator, electronic components, and the engine computer.
Your unit most likely has a converter that will provide a 13.6-volt charge when the batteries are low and then drops to a 13.2-volt charge as a maintenance stage. However, if you have a large inverter or solar charging system, it might have a multi-stage charge. That would throw 16 volts as an initial bulk stage charge to break up sulfation which would not be good for your engine battery and electronics.
Charge the house batteries while you drive
Your unit should have a Battery Isolation Manager solenoid (BIM) that provides a charge from the engine alternator to the house batteries while you are driving. There should be a switch on the dash that also allows you to provide a jump start to the engine battery from the house batteries. This is a spring-loaded switch, as it can only be a temporary jump.
As for the second part of your question, yes, it is OK to use a trickle charger such as the Battery Tender (or, my choice is the Battery Minder) plugged into either an outlet inside the rig or, better yet, plugged into the 20-amp residential outlet on the campground pedestal. It is typically easier to run an extension cord from the pedestal under the rig and up into the battery compartment.
Your rig has the chassis battery either in the stepwell, which is open to allow venting, or up in the front engine compartment. Either way, you could permanently mount the device in the compartment and have an extension cord plug placed in an accessible location.
One last comment. Most motorhome batteries do not need a charge for the amount of time you are camping. Unless you are staying in one location for a very long period of time, an engine battery in good condition should stay charged for at least a couple of weeks.
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.
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