Community Forums

Modersical · 08-13-2017, 11:33 AM

I recently purchased a 2017 Ford Transit 3500 23' Compass MH by Thor. It appears it was made about 6/16. There are 2 12V wet cell "27" batteries.

I too, am having what I thought was house batteries draining too quickly. I understand several items like propane sniffers and the like are still powered, even if battery switch is in "storage" position. I also understand that the fridge, even on LP, still needs 12V to power the circuit board of the fridge.

I was surprised that with the fridge on LP, that the house batteries went from full charge to insufficient to start small Onan in less than 2 days. The fridge had turned itself off, and was defrosted, and there was barely enough battery left to barely turn the generator over for a few seconds . . . not enough to start it.

After recharging, I switched the "Storage" switch to "off". A week later, 6 days, actually, the batteries were again depleted to to a level insufficient to start the little Onan.

The RV dealer says this is normal battery life/usage/depletion.

Is this true?

Is there any way to maintain the charge on the batteries longer than a week; or run the fridge longer than 2 days (without recharging)? When not using the MH, do I disconnect the batteries, or put in a manual battery disconnect switch?

If the MH is unoccupied, it seems little to no risk not powering amp greedy protective devices. Besides, after a week of storage, they are ineffective anyway; are they not?

F76Marion · 08-13-2017, 11:41 AM

There are two possibilities here, and you may not like either.

First is that there is a phantom load miswired around the battery switch. To check for this, disconnect either side of the battery and use alligator clips to put a small light bulb in series. It should not light. If it does, you have to find out what that is and move it to the other side of the switch.

Second, and you will like this less. 12V jars seldom play nicely in parallel. If they are not EXACTLY matched, the low one will take down the better one.

Try pulling the cables off when you leave it and measure the battery voltage before reattaching the cables.

Frank

Modersical · 08-13-2017, 12:38 PM

How long, generally, should it take the Onan to put a full charge on good batteries after being pretty much depleted after a week of normal storage?

Terminex · 08-18-2017, 01:25 PM

I did a LOT of research before I purchased my RV 3 years ago.

One of the most common problems I foudn was that there wass always something that was wired directly to the house batteries, and NOT going through the switch.

First thing I did in my RV was to add a switch in the battery bay that truly disconnects the batteries when not in use.

If I do not use that switch, and simply use the one in the RV, the batteries can drain in storage within 10 days.

using my manual switch I have no problems over winter when once a month I go and start the genny to run it for several hours to exercise it and charge up the batteries.

a battery disconnect is cheap (can get one at amazon) and it is easy to install. I personally did a switch that allows you to use battery 1, or battery 2, or Batt 1 & 2, or all disconnected. I did not add the second set of batteries until a year later, but I wanted to be prepared for that possibility in case.

https://www.amazon.com/Blue-Sea-Syst...BKZXR1YER&th=1