Why is LP fridge pulling 47 watts?

[Eggs Benedict]

Hi folks,

I recently installed a solar system and have been using it successfully for my 24/7 power needs. Working on minimizing usage so I can get my 200ah battery bank up to 100% during daylight hours. I'm using LP for cooking, the refrigerator, and water heater. When every other power drain is turned off at the breaker box, it appears the 2-way fridge is using a fairly constant 47 watts, even when on propane. I can't imagine the reigniter would need to draw constant power?? Would the reignitor draw this much power just because it's old (2007)? Are there other parts back there that are using constant power? There is no light or fan on in the fridge. I have filled half the fridge with pieces of ethafoam, since I really don't need to store much food. If I could figure out how to get the freezer to cool above freezing, I could use it alone as a fridge, for that matter, since I really don't have to have anything frozen.

If I let the fridge operate at its lowest setting (thermistor at the lowest position on the fin), it depletes 50% of my battery bank overnight, when ambient temp is lowest and I can't discern an wattage advantage for running a cooling fan on the back of the fridge.

Side note: the bath hatch fan draws 60 watts! I'm going to order a new motor, since corrosion may be making this one work harder. Most sales sites don't include the wattage of such motors. Advice appreciated.

I have the panels wired in series-parallel and they are delivering an average of 175w in sunlight, but only charging the system up to about 60% over the course of a day. I have to wire up a connector pigtail with larger gauge wire, and then I'll be able to re-configure the panel wiring to deliver more wattage, and so charge faster. It's not a hair-on-fire issue, but I will be continuing to adjust stuff until average usage is predictably within the charging capacity of the system, and I don't have to strategize so much to get through the day.

Thanks in advance for info and advice.

[flybouy]

First question. How did you determine that the fridge was drawing 47 watts? That's between 3 and 4 amps depending on the voltage. A typical parasitic draw from the radio, CO/ LP leak detector , etc. could easily reach that number.

[Eggs Benedict]

Thanks, Marshall! I turned off the breakers for everything except the circuit the refrigerator is on. Pulled the fuse for the radio. The CO detector has its own 9v battery. Unplugged my phone charger. However, I did not think to check whether the LP leak detector is on the circuit with the refrigerator. That may be it! If so, I guess I'll just have to live with that amount of constant draw.

[chuckster57]

Even though your fridge is on LP, it will still draw to power the control board, eyebrow and any indicator lights. You can use a DC amp clamp at the power connections to measure it.

[travelin texans]

Originally Posted by Eggs Benedict

Thanks, Marshall! I turned off the breakers for everything except the circuit the refrigerator is on. Pulled the fuse for the radio. The CO detector has its own 9v battery. Unplugged my phone charger. However, I did not think to check whether the LP leak detector is on the circuit with the refrigerator. That may be it! If so, I guess I'll just have to live with that amount of constant draw.

NO! Your CO/LP detector mounted low typically near the kitchen will be/should be wired directly to the batteries, no batteries, fuses or breakers. DO NOT disconnect!
Any smoke detectors mounted on the ceiling will have 9 volt batteries.
Any LED illuminated switches, the fridge & water heater control boards to run on gas will all have minute amp draws.

[JRTJH]

I would guess that your refrigerator is the OEM unit, built in 2006 or 2007 and is a Dometic 6 cuft gas/electric model, probably a model RM2652 ???

If so, there is a heater circuit in the door frame that rests against the gasket that warms the gasket to prevent condensation from causing water droplets from forming on the refrigerator cabinet and dripping onto the wood enclosure. Dometic calls it the "Low Ambient Climate Control System". IMO, that's just a long name for "battery power waster".....

In the "upgraded model RM2662, there is a off/on switch just under the eyebrow controls that allows you to turn the door heater circuit off. There is no such switch on the RM2652 models.

On my RM2652, that circuit draws about 42 watts.

I'd guess that your measurement of 47 watts is around 42 watts for the refrigerator door heater and 5 watts for the LPG detector.

Here's the way Dometic explains it in the Owner's Manual:

[Eggs Benedict]

Oh, I wouldn't disconnect it! Whatever power the gas leak detector consumes, I'll just have to live with it.

[Eggs Benedict]

Originally Posted by JRTJH

I would guess that your refrigerator is the OEM unit, built in 2006 or 2007 and is a Dometic 6 cuft gas/electric model, probably a model RM2652 ???

If so, there is a heater circuit in the door frame that rests against the gasket that warms the gasket to prevent condensation from causing water droplets from forming on the refrigerator cabinet and dripping onto the wood enclosure. Dometic calls it the "Low Ambient Climate Control System". IMO, that's just a long name for "battery power waster".....

In the "upgraded model RM2662, there is a off/on switch just under the eyebrow controls that allows you to turn the door heater circuit off. There is no such switch on the RM2652 models.

On my RM2652, that circuit draws about 42 watts.

I'd guess that your measurement of 47 watts is around 42 watts for the refrigerator door heater and 5 watts for the LPG detector.

Here's the way Dometic explains it in the Owner's Manual:

JRTJH: YES! This is exactly it! Aha! Thank you so much! My fault for not digging beyond the spec sheet for the refrigerator. Now, I wonder if I can splice into that circuit and install a switch.

[Eggs Benedict]

Does anyone have remarks on adding a fan/fans to the "chimney" behind the refrigerator? Particularly, fan kits with a little solar panel mounted to the vent cover? The pre-made vent cover with photovoltaic cell installed seem to be discontinued. Why do you think they didn't succeed in the market?


Dometic is offering a (wired) fan kit on their site, so they seem to be advocating their use. Just wondering what your experiences are.

[flybouy]

Originally Posted by Eggs Benedict

Does anyone have remarks on adding a fan/fans to the "chimney" behind the refrigerator? Particularly, fan kits with a little solar panel mounted to the vent cover? The pre-made vent cover with photovoltaic cell installed seem to be discontinued. Why do you think they didn't succeed in the market?


Dometic is offering a (wired) fan kit on their site, so they seem to be advocating their use. Just wondering what your experiences are.

Strictly a guess on why they were discontinued. I imagine because folks found them a waste of money. Those little solar cells just didn't provide enough energy to operate a fan of sufficient flow.

[chuckster57]

I wouldn’t add a fan to the chimney, that’s where the “heat” is needed to boil the ammonia solution. The fans are to help remove heat from the coils at the top.

[Old_Stevenick]

I had a similar issue when I bought my camper. First thing I did was put my iPhone in my fridge recording a movie and closed the fridge door. The light didn't go off! Fixed that and the draw reduced. I also replaced the bulb with an LED. The fridge does draw power even when running on Propane as others have mentioned.

Eventually I bought a second 100ah LiFePo4 battery. The 200ah's total did the trick for me.

Ampere Time batteries are down to about $350 for 100ah on Amazon.

[Lee]

Originally Posted by Eggs Benedict

JRTJH: YES! This is exactly it! Aha! Thank you so much! My fault for not digging beyond the spec sheet for the refrigerator. Now, I wonder if I can splice into that circuit and install a switch.

Yes, you maybe able to add an on/off switch to the circuit. I did on my TT.

In my TT the circuit gets it's power from the same circuit that operates the door lamp inside the fridge. I removed the lamp lens, unscrewed the lamp housing from the fridge wall and wired in an on/off switch that hangs below the lens.

[Eggs Benedict]

Originally Posted by Lee

Yes, you maybe able to add an on/off switch to the circuit. I did on my TT.

In my TT the circuit gets it's power from the same circuit that operates the door lamp inside the fridge. I removed the lamp lens, unscrewed the lamp housing from the fridge wall and wired in an on/off switch that hangs below the lens.

Great idea! I'll do this!

[JRTJH]

Originally Posted by Eggs Benedict

Great idea! I'll do this!

Here's a few links that discuss adding a switch/disabling the door heater circuit. They include photos to show how the system is installed and how to modify it to add a switch. As you can see, they are from 2018 or so, and the issue is nothing "new with Dometic".

https://www.keystoneforums.com/forum...+heater+switch

https://www.keystoneforums.com/forum...heater+circuit

The switch assembly used is in post #27 in the above link. While Amazon indicates "current unavailable", there are alternatives easily found with a little "snooping around Amazon".

[Old_Stevenick]

OK so in the Spring when my TT is uncovered and batteries put back in I'm going to do something to disconnect the fridge heater.

We almost never run on AC, so having this off would be great.

The question no one answered in those other threads that you linked to is what is the disadvantage of having the heater disconnected?

I'm thinking of just cutting it. That's a large parasitic draw.

[Lee]

Originally Posted by Old_Stevenick

The question no one answered in those other threads that you linked to is what is the disadvantage of having the heater disconnected?

I'm thinking of just cutting it. That's a large parasitic draw.

Disadvantage I sometimes see on TT is a build up of condensation on the strip of frame between the freezer and fridge doors. When really bad it drips down onto the seal of the fridge door.,

[Old_Stevenick]

Thanks. Sounds like a switch or at least a hillbilly switch is better than just cutting it, in case condensation builds up.

We have 200 a/h and get about 5 days before needing the generator. That's 40 a/h per day.

If that door heater draws 8 a/h that's 20 a/h per day. Almost ½ our usage to heat the fridge door!

We could possibly get 10 days, or at least 7 in cold weather when running the furnace.

[JRTJH]

Originally Posted by Lee

Disadvantage I sometimes see on TT is a build up of condensation on the strip of frame between the freezer and fridge doors. When really bad it drips down onto the seal of the fridge door.,

The quote is the "almost instantly visible" disadvantage.

The long term disadvantage that I see regularly on both intentionally disconnected door heater circuits and on "broken without knowledge" door heater circuits (yes, who among us ever tests for a temperature change or does an amp check to verify the door circuit is operational)... Anyway, the long term disadvantage is corrosion under the painted metal cabinet frame member between the freezer and the refrigerator doors and flaking paint on that metal strip. It's no consequence initially, but can lead to leaking door gaskets and loss of cooling capacity in the freezer as the flaking paint allows colder air to "seep out of the freezer" making the door frame cold, increasing the moisture and increasing how fast the corrosion progresses.... Most owners don't recognize the corrosion, thinking "It's just flaking paint, no problem"....

But, I modded mine to add a switch and I notice increased condensation "AT TIMES" on the door strip, but a quick wipe with a paper towel or a kitchen dishrag usually takes care of it. We use the switch and paper towel when dry camping and turn the switch on when we're connected to shore power, but often forget to turn it on or turn it off, so it's not a "vital to do" kind of mod or even necessity to remember the switch kind of setup step.

[WDPatterson]

When in propane mode, the refrigerator operates on your 12 volt DC circuit. 47 watts is negligible, compared to the load that anything else puts on your system. I would be more concerned about 175 Watt PV panel. You need more wattage coming in from your PV panels. I would recommend upgrading, putting larger panels on the roof of your TT.
The idea is to have enough battery to handle the minimal loads you create, but it should always be capable of taking care of the maximum, as well. What exactly are you using your batteries for?? Do you have an inverter?? If so, it is absolutely necessary to provide more input, and a better charge controller, so that you have enough power coming in with the sunlight available.
Again, the reason that your battery is not charging fast enough is that you are only providing 175 watt maximum through that panel. The overhead in your system is taking most of that away. And, there are just some things that you should not Whittle away.