charging house batteries

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Herdingdog wrote:
We have a 2012 Coachman Mirada. Do the house batteries charge while driving or do they only charge when plugged into shore power or with the generator running? A week ago I went to check the RV like I do every month and I could't get the generator to turn on from the switch or from the dash. I always use the battery disconnect when I turn off the electricity to the coach when it sits. The generator started when I brought the RV home. I'm hoping that I don't have to buy new batteries. Any help would be appreciated. Thanks

Herdingdog,
Your '12 Coachmen Mirada DOES charge the house and chassis batteries while the coach is under way. There are numerous systems out there that accomplish this task. You'll have to enquire into your owners manual or, your dealership, or online to find out just EXACTLY which system you coach uses. There people on here that think all RVs have the same charging systems, gas, diesel, Class C, Class A etc.

That is not the case. There are many differences. Anyway, normally, if you shut down the house batteries from the coach, with the "salesman's switch" or, "Battery Switch", it will normally shut down about 99.9999% of the draw or, potential draw on those house batteries.

Sometimes, there are still tiny, parasitic draws on them but, not normally. Shutting off a battery, via the switch, means just that, SHUTTING IT OFF. In some cases with some diesels, the Inverter/charger will still charge the house batteries even with the battery switch in the OFF position.

You need to perform a test to see if you do in fact, have a draw on them when the battery switch is in the OFF position. It's a simple test. First, a full charge to them is applied, either via running the engine for a while or, plug the coach into shore power for a day or two. Then, you shut them off, via the battery switch. Then, disconnect the negative battery cable from the house battery.

Then, if you have a test light, the kind with the ice pick end and the alligator clip on the wire end, put it in line between the negative battery cable and the battery post.

If it lights up, you still have some sort of draw on the house battery. If it doesn't, you may still have a draw but, it's so small that it's not enough to light up the test light. But, if it does light up the test light, you can to into the coach and, one by one, pull the 12V appliance fuses, water pump, lights, and any other 12v fuse, and see which fuse, when pulled, turns that test light out.

If you find one that does, that's your troublesome circuit. You'll have to investigate as to why and what, the problem is. Good luck.
Scott

Start the engine and put a VOM on the batteries. We don't know.

The isolators purpose is to charge both batteries while driving. Your charger will charge the house batteries and may charge the chassis battery depending upon how the MH is configured..

A dead battery in storage is a different issue. Start with load testing he batteries and install full disconnects on the batteries for storage.

Assuming everything is working properly, they should charge while driving from the engine alternator. It's always possible that a fuse or solenoid or connection is broken that prevents that. However, from your description, I think that's unlikely to be the case since they did appear to charge while driving.

If they're the factory disconnects, they don't disconnect all of the power. Either have some aftermarket disconnects installed or simply take the negative battery cable off of both sets of batteries like I do when I put the DP into storage.

Bill