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marycontrary · 04-11-2021, 07:52 PM

Can anyone tell me why my two brand new batteries won’t hold a charge? I’m parked at a friends place, not plugged in, but using absolutely no battery! Frig on propane, furnace off. What’s the explanation?

Phil G. · 04-11-2021, 09:49 PM

Quote:

Originally Posted by marycontrary

Can anyone tell me why my two brand new batteries won’t hold a charge? I’m parked at a friends place, not plugged in, but using absolutely no battery! Frig on propane, furnace off. What’s the explanation?

The only way to make sure your RV batteries aren't being drained small but steady amounts by stuff when the RV is not being used is by either disconnecting one of the cables attached to them ... OR ... if your RV has a coach battery disconnect switch ... making sure that switch is turned OFF when not using your RV.

I keep forgetting to turn OFF my coach battery disconnect switch and then wondering why a steady 1/2 or more amps of current are flowing out of the RV batteries day-in and day-out whenever it's sitting in non-hooked-up storage. It turns out that my propane gas detector is always on and drawing that amount of battery current 24/7 if that switch is left ON.

The above "could" be your problem. Post here the cause if you find out.

cavie · 04-11-2021, 10:01 PM

Quote:

Originally Posted by marycontrary

Can anyone tell me why my two brand new batteries won’t hold a charge? I’m parked at a friends place, not plugged in, but using absolutely no battery! Frig on propane, furnace off. What’s the explanation?

The fridge on propane uses 12 volts DC for control circuits. WH uses 12 volts DC for control circuits. CO and LP use 12 volts DC. Stereo uses 12 volts DC for the memory circuit. Lights are 12 volts DC.

Even if you turn off the battery disconnect switch you still have CO, LP, and Stereo drain.

Det57 · 04-11-2021, 10:16 PM

What they said above......and.....double check you havent left the lower baggage compartment lights on. I did that once. Cant tell with the doors closed........

Arch Hoagland · 04-11-2021, 10:19 PM

Do you have an inverter? If so it will drain your batteries just sitting there.

Turn it off.

Phil G. · 04-11-2021, 11:58 PM

Quote:

Originally Posted by cavie

The fridge on propane uses 12 volts DC for control circuits. WH uses 12 volts DC for control circuits. CO and LP use 12 volts DC. Stereo uses 12 volts DC for the memory circuit. Lights are 12 volts DC.

Even if you turn off the battery disconnect switch you still have CO, LP, and Stereo drain.

The above statement "depends" ... the disconnect switch on some/many RVs does indeed turn off all coach battery power to the RV. For instance, in my motorhome the coach batteries supply no current when the switch is OFF. I have a meter permanently mounted that shows current out of or into the coach batteries at all times. The LP detector light goes out when I switch off the disconnect switch.

twinboat · 04-12-2021, 03:23 AM

Quote:

Originally Posted by Phil G.

The above statement "depends" ... the disconnect switch on some/many RVs does indeed turn off all coach battery power to the RV. For instance, in my motorhome the coach batteries supply no current when the switch is OFF. I have a meter permanently mounted that shows current out of or into the coach batteries at all times. The LP detector light goes out when I switch off the disconnect switch.

I have the same on my MH. Battery Disconnect / Use / Store Switch shuts off everything.

My dash radio loses settings and the propane detector shuts off. Nothing is on.

marycontrary · 04-12-2021, 06:56 PM

So today, when I went to a dump station, just as it was mentioned above, one of the cargo bay lights was on! I did not turn it on, something must have pushed up against it! I’m hoping and praying that is the problem. Right now, the batteries read full again, but I drove for two hours, so...
Ok, I admit to being a newbie, but are you supposed to turn off the battery when parked for a few days? That doesn’t make sense if you need power for lights, etc, am I missing something here? I just had these batteries installed four days ago...

Mark_K5LXP · 04-13-2021, 07:02 AM

Obviously you don't shut the main disconnect off when the RV is occupied but for me anyway it's SOP when parked/stored. Even a small parasitic load like the propane detector will draw down even a large house battery eventually. Lead acid batteries degrade when stored at any state of discharge other than 100%, so any time they sit you don't want them drawn down.

If the bay light was incandescent, something like an 1141 will draw an amp and a half. Over a 24 hour period that's 36 amp hours. Throw in a few other loads like the fridge, propane detector, other lights and miscellaneous loads and yep, after a few days your batteries are flat.

2 hours driving time is not enough for a full charge, so I'd be looking to plug in somewhere to finish that.

An inexpensive battery monitor will provide you with how full your batteries are and what load it's seeing at any given moment. You would've seen the current being drawn by the compartment battery and been able to hunt it down before the battery went flat.

Mark B.
Albuquerque, NM

THenne1713 · 04-15-2021, 08:17 AM

Quote:

Originally Posted by marycontrary

So today, when I went to a dump station, just as it was mentioned above, one of the cargo bay lights was on! I did not turn it on, something must have pushed up against it! I’m hoping and praying that is the problem. Right now, the batteries read full again, but I drove for two hours, so...
Ok, I admit to being a newbie, but are you supposed to turn off the battery when parked for a few days? That doesn’t make sense if you need power for lights, etc, am I missing something here? I just had these batteries installed four days ago...

There are specifics about YOUR RIG that you will have to learn/ decipher, that are NOT written in any book. MAKE NOTES AS YOU LEARN? As others say, REFRIG on LP is still a battery load, as LPG solenoid valve and controls are operated by 12-vdc, but (some brands/ models/ years) also have an additional safety SOLENOID back on the LP TANK Tied to the (3-wire LP/CO detector) that can be a heavy load battery drainer. Some owners find the battery switch does NOT turn off the CO/LP Alarm and that tank solenoid. You don't mention your rig specific brand/ model/ year? The Battery Switch WILL kill the Refrig if OFF, so you will need to RECHARGE occasionally if running Refrig. If you have access to even a 15a receptacle plug-in, use a DOGBONE ADAPTER and all will be good.