I recently bought a 1999 Wanderer Fifth Wheel.  This past weekend we took it out for the first time.  Everything worked fine, but we learned that the fridge really drains the batteries.  We don't have a generator and the our camping spot didn't have hook ups.  After 24 hours the batteries (2 12 volt) were dead. I forgot to pack my voltmeter but they were drained to the point that the interior lights were at about 25%. 

 

The fridge is a 3 way Norcold 9162 freezer on top and fridge on the bottom.  It was doing fine in AC mode at home and LP mode for the first 24 hours.  I noticed that all of the lights on the fridge were blinking/flashing indicating that something was wrong.  I couldn't get it to work in LP mode until I plugged the truck in--everything worked as advertised.  According to the fridge's manual, the fridge will not work in any mode if the battery drop below 10.5 vDC.  I thought this strange as I was in LP mode and didn't imagine the small lights on the display required that much power to operate.

 

Going through the manual and the Interwebs I found that this fridge has a Moisture Reduction Heater between the freezer and fridge portions and pulls as much as 2 amps when in use.  As far as I can tell, there is no switch to disable this, but I imagine that I can either unplug the element or cut a wire to get the job done. 

 

Does anyone have experience with this?  Would there be adverse consequences for disabling the heater?

 

I am certain the fridge is the culprit of the dead batteries.  As soon as I turned off the fridge the interior lights in the trailer got brighter and it has been parked in my yard with the fridge off for 3 days and the batteries are holding solid.

Thanks for the help.

Ok...

 

DC operation is only advised if you hooked to your truck and travelling.

 

LP mode should be used if boondocking.

 

AC mode should be used if hooked to city power.

 

All I can say is start over with a fully charged battery and make sure your using the proper mode. I typically leave mine locked on LP mode. On a fully charged batteries it will go over 2 weeks without recharging just the fridge alone.

Mike,

 

Even in LP mode this fridge requires at least 10.5 vDC to maintain this "Moisture Reduction Heater".  It is to keep condensation from building up--I think.  I had the fridge set to LP mode.  After some searching on the internet I found that other refers have this same heater but many of them have the option of switching it off.  My fridge does not have that switch, hence the reason I would like to take the element out of the equation. 

Still in all 2 Amp draw should last a long time vs. 200 Amp hours of batteries. At least 4 days calculated to fully dead. What killed your batteries is the main heater which draw lot lot more amperage. Roughly speaking the main heater on 12V is 40 Amp draw which would deplete the batteries to full dead in about 5 hours. But since its only allowed to 10.5 volts the time is even shorter. Like I said charge the batteries back up and switch to LP I'm sure it will work just fine even with the heater.

My suggestion is to call Norcold. 1-800-543-1219 Apparently you need to go through a bunch of "press 1 for service" type prompts, but from what I understand they are quite helpful.

What voltage where your batteries at? They need a recharge at 12.2V, if you are at 10.5V you could have damaged your batteries. Batteries are dead at or below 11.6V, 10.5V is just bad.

 

I would verify the battery state of charge and battery acid level, it could be low and give you a shorter life. I would also verify your charger is working properly.

 

I am going to assume you have G24 batteries, for a max of 170 AH. 2A draw, as Michael pointed out, will give you about 85 hours until DEAD, or 42.5 hours until the recommended 50% recharge state. There are other amp draws, with our fridge on we have a residual draw of about 1.2A fridge not cooling and closer to 1.5A fridge cooling (non-pilot version). The furnace draws 6.5-7A, same as the water pump.

 

If your batteries died that quickly I wonder if the fridge was truly in LP mode, sounds more like DC mode. In order to drain your batteries in 24 hours you would need an average amp draw of ~7A, that's a lot. The most I have ever seen is ~17A with furnace, lights, and water pump on. I do have LED's, so the amp draw for them is lower.

In my old camper, I had a big problem with the fridge running batteries dead too. I figured out the the heating element was shorted out. It was shorted after it went through the fridge so some how it still worked but it drained my truck batteries in a few hours. Then again, that fridge was almost over 30 years old too and I am sure the technology for how RV appliances have changed a bit. Just a thought though.

 

On a side note, even if your fridge was working 100% correctly like said before it shouldnt drain the batteries that fast. Either the batteries were weak, under charged, or maybe a bad connection to them somewhere. That could make it look like the batteries were dead.

Corrected my post above for DC operation not 12V to keep other from getting confused.

 

But even my Norcold with 2 standard lead acid batteries, 45w (3 Amp charge) solar panel and 1,200w inverter (100 amp draw @ 1,200w) sit around for 2 days watching TV and drinking beer no problems with batteries running dead. It's all about being aware of the loads. I do think your attempting DC operation and ate the batteries in a short order. My Norcold is only a AC or LP operation no DC function. Still in all it best to operate in LP mode, propane is cheap and last a very very long time compared to DC operation eating the batteries fast or putting load on the tow vehicle alternator. AC only works if hooked to city power or genny. Well in AH64ID case his inverter but still even then the load is place back on the tow vehicle. The biggest propane eater is the furnace, next is water heater, then fridge.

Michael, have you measured your furnace draw at 40A? That seems really high, mine is less than 20% of that.

No. That was calculating backwards for the heater of the fridge in DC mode. Using the wattage of the 120V side then calculating the 12V amp draw. No measurement yet for my furnace.

No. That was calculating backwards for the heater of the fridge in DC mode. Using the wattage of the 120V side then calculating the 12V amp draw. No measurement yet for my furnace.

 

 

Main heater, as in heat element in the fridge? I misread your post if that is the case.

 

I still doubt it's that high. I draw 23A of inverter power, which is less efficient.

 

 

 

 

EDIT: I just found the specs, it's a 16A DC heater element.

 

Also, the OP noted 9162, which is a 2 way fridge. The 9163 is the 3-way version.

 

The ignition draws .50A, the heater draws .11-.17A, and the interior light draws .6A.

 

The heater is not the issue, unless it is shorted.

 

 

 

 

So here is a question. OP, was it in AUTO, LP, AC, or DC mode? If it was in AUTO and you ran out of propane, or it failed to light the fridge will switch to DC.

If 9162 is a 2-way model I must be wrong about it being a 3-way.  The controls on the fridge have an option for AC/LP/DC.  I was operating the fridge in Auto and it stayed in LP.  I could here the burner outside at the access panel.  As soon as the batteries drained it would shut off and it would not light.  The propane tanks are full, I filled them up 10 minutes before we got on the road.  As soon as I hooked up the truck the fridge's burner would light up and run like a champ--until the battery's voltage dropped. 

 

I plan check the water level in the batteries.

 

Thanks for the suggestion.

If you are sure about the model number then you have the 2 way fridge with the multi-unit display panel. 

 

Sounds to me like you have another LARGE DC draw, a loose connection, or bad batteries.

with AH64ID...

 

1. Charge up the batteries

2. Check water level in batteries

3. Load test batteries

4. Verify all your wiring connections are good and clean

5. Look for heavy draw

Just as a piece of nice to know information:  the refrigerator operating in LP mode has a normally closed "gas" valve that is operated by dc voltage.  If the power level of your batteries goes too low to keep the solenoid on the gas valve open (I don't know what that level specifically is) then the "nc" valve will shut off the gas supply and the 2-way frig will stop operating when not hooked to shore power or a genny.

 

I am not saying this is the cause of your low batteries but I am saying without sufficient dc power your gas valve will not stay open so the refrig can operate in LP mode.

So maybe I found the reason for my batteries depleting so quickly.

 

I left the trailer plugged in to charge for 2 days.  After unplugging the trailer the batteries were sitting at ~12.7 vDC. So, Monday afternoon, with a full charge on the batteries, I started up the fridge.  I measured the draw with just the fridge running at it is about .5 amps.  I checked it the next morning and not much change on the volts, the same for Tuesday afternoon.  By Wednesday morning the batteries were sitting at ~12.4ish.  I started thinking I was ok and my trip was a fluke.  By the time I got home Wednesday afternoon the batteries were reading 10.6 vDC.  Nothing had changed as far as what was turned on, just the fridge and the gas monitor.  The total draw for the trailer was around .7 amps.  Trying to figure out why the batteries would deplete so quicklly in a 10 hour window I looked at connections and cleaned what i could.  I pulled the batteries and water levels were normal.  I just bought this and the seller told me he bought these batteries last year and they look great. 

 

However, when I pulled them out of their hole I was able to see that they are Marine Starting Batteries.  I am assuming this is the reason why they die so quickly.  Before I run out an buy a pair of deep cycle batteries, is this how starting batteries hold up in an RV??

 

Thanks for the help.

Yeah it seem you got the wrong batteries. Deep cycle batteries are about how many amp hours there are compared to cold cranking amp.

I would recommend that you put two golf cart batteries in it. They are six volt and they are huge and really hold power.

I would recommend that you put two golf cart batteries in it. They are six volt and they are huge and really hold power.

 

 

Hence what powers my stick and bricks... 6V deep cycle batteries are very popular and tend to have better storage and amp/hour ratings.

 

http://www.trojanbattery.com/markets/mr/6v/

When I bought my camper new and first used DC mode I learned real fast to never use it again. It drained down two new batteries very rapidly.

 

I want to say again that you should almost never use the DC mode of frig operation. It just kills the batteries and is hard on your alternator, if I'm correct in saying that.

 

So I always use the LP mode  even while traveling, but, shut it off before fueling the truck. A post-it note on the steering wheel always reminds me to turn it back on.

Edited June 19, 201410 yr by JAG1

Looks like a control center for a nuclear power plant.