My group 29 battery is discharging down to 12.34 after only 2 hours while dry camping with the fridge on propane. The fridge is 3 way, but is turned to automatic, and the gauge shows propane being used, which it actually is. The battery seems to be okay when not hooked up to the rig as I have charged it, left it aside and it still holds it charge. I put another battery in and it also came down to 12.34 after 2 hours, so the battery is not the problem. The only other thing I have on the trailer is a propane detector which is hooked up to 12V. After 12 hours the battery goes down to 12.24. Suggestions please.

You don't say what voltage your battery starts out at. More information is needed.Turn your fridge to "gas" only.

How do you know the fridge is using propane? Most fridges set to auto sense there is 120v and automatically switch to electric, 120v. Take Niner's adviceIf you have a clamp-on ammeter measure the battery current.

Your big drain is going to be your ceiling lights. Each 12VDC automotive type lamp will draw a good 1A DC CURRENT. Another hugh drain would be the furnace fan which draws around 4-5AMPS when being used.Your charged up battery should start out with 12.6-7VDC being fully charged.Here is simplified 30AMP Trailer Electrical Diagram showing what would be on the BATTERY if you are unplugged from shore power. As you can see alot of items are connected to the battery system so that your basics will run from the battery when not connected to shore power.Most people will want to have two batteries installed if they are going to do some camping off the power grid giving them at least 220AHs of battery capacity.We get by just fine with my 255Ahs battery capacity for camping off the power grid and we use just about everything we do at an electric site with the exception of the air conditioner and the high wattage microwave. We have planned it out to use all kinds of 12VDC items and 120VAC items running from an Inverter and have the battery bank only drop to 12.0VDC (approximately 50% charge state) by 8AM the next morning. Then we connect our 30A Shore Power cable directly to our 2KW Honda Generator using at RV30A-15A adapter and can re-charge our batteries back up to their 90% charge state in as little as three hours generator run time. Three hours generator run time usually fits in with all the camp ground generator run restriction times here on the East side of the US. Where we go the generator is never allowed to be used after 8PM.The main thing we did was to install a good multi-stage converter/charger unit, larger battery cables, additional batteries, and changed out the automotive type bulbs for LED boards.We have been doing this method of camping off the power grid since late 2008 and are pretty successful about it now.It does take some planningRoy Ken

Thanks for the replies. When I charge the battery, it goes to about 13.3 and settles at 12.66 the goes to 12.34 after 2 hours. I have not used any of my LED lights, just the fridge during this period. The Dometic fridge does not give me an option to turn to gas only, just auto, but shows gas. When I go to the fridge opening on the exterior, there is heat there, so gas is definitely being used.

Are you saying the charging voltage is 13.3v? At that voltage it takes about 4 days to fully charge a battery. If that's the voltage after charging, its surface charge and will slowly leak off. 12.66v indicates a fully charged battery.The fridge uses heat to cool the fridge. The heat is produced either by gas or by electric, Just feeling heat does not mean it is produced by gas. Can you see a flame?

Battery Discharging | Good Sam Community

westend
Explorer
Jun 14, 2014
You will need to use a meter to measure current draw. I would measure at the fridge and also at the battery. There are way too many variables for anyone to point directly at the problem, if there is one.

How old is the battery that you are using for this?
jimlouisesophie
Explorer
Jun 14, 2014
The fridge was turned to gas, not auto as suggested and it went down to 12.25 after 12 hours which is better than when I had it on auto. However when I have the fridge off, and fully charge the battery again, it stays at 12.69, so obviously there is a draw at the fridge. How can I find out the problem. Thanks, Jim
wa8yxm
Explorer III
Jun 13, 2014
Group 29 is about 105 amp hours (just over 100)

if you can replace it with a pair of GC_2 Golf car batteries you get 230 amp hours, and DEEP CYCLE types are better able to recover from a excessively deep discharge than Marine/Deep cycle 29's are.

As others have said, Make sure the fridge is LOCKED on gas, not auto, and turn off all lights, You still have other loads (Control boards, propane detector) but most of those are minor. And put a clamp on DC ammeter on one of the battery leads,, Whichever end has but one cable attached.
dougrainer
Nomad
Jun 13, 2014
Post the model number of the refer. ANY source(lp/12/120) will have HEAT at the back side. Doug
wwest
Explorer
Jun 13, 2014
12.73 volts +/- a few % based on ambient temperature of/at the battery.
jimlouisesophie
Explorer
Jun 13, 2014
While I had the trailer parked in the driveway, previously without the fridge on and without shore power,I had the 12 v battery hooked to the trailer for a week, and the battery never got below 12.4 Now with the fridge on, it is discharging to 12.34 Could it be that the 3 way fridge is on DC only, and how would I check that, even though the fridge monitor shows auto and propane, not AC. Sure is puzzling.
NinerBikes
Explorer
Jun 13, 2014
You need a better charger, that puts out 14.8V, and your battery voltage, fully charged, and disconnected, should be at 12.73V
tenbear
Explorer
Jun 13, 2014
Your grp 29 battery probably has an AH rating of about 120 AH. 12.3V indicate about 30%, or 36AH has been used in 2 hrs, that's a current of 18Amps. The fridge circuit is probably fused at 15A. Hard to believe the fridge is drawing that kind of current on gas.
tenbear
Explorer
Jun 13, 2014
I would say your battery is not getting fully charged. 13.3v is a very low charging voltage. Without knowing how much current is being drawn from the battery, its hard to say. The fridge should only be drawing about 1/2 Amp and should not draw the battery down that fast.

Just noticed you said the fridge is a 3 way fridge. Could it be running on 12v and not using the gas? That would certainly draw the battery down fast.
jimlouisesophie
Explorer
Jun 13, 2014
I do not have shore power on at these testings, just my 12 volt battery, so definitely am using propane as the fridge temp seems normal. I used a battery charger hooked directly to the battery, and it goes up to 13.3 at the peak, but when I unhook the battery charger, then it does go down to 12.6, which, as previously noted is the norm.

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