Why is LP fridge pulling 47 watts?

Eggs Benedict · 10-24-2022, 01:27 PM

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** · 10-24-2022, 01:43 PM

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 · 10-24-2022, 01:56 PM

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** · 10-24-2022, 02:05 PM

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 · 10-24-2022, 02:18 PM

Quote:

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** · 10-24-2022, 04:52 PM

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 · 10-25-2022, 07:55 AM

Quote:

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.

Lee · 10-26-2022, 06:43 AM

Quote:

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 · 10-25-2022, 08:12 AM

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** · 10-25-2022, 08:52 AM

Quote:

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.

Eggs Benedict · 10-25-2022, 07:46 AM

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

Old_Stevenick · 10-26-2022, 02:20 AM

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.

Old_Stevenick · 10-27-2022, 11:11 AM

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.

WDPatterson · 10-30-2022, 11:11 AM

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.

Eggs Benedict · 10-31-2022, 08:23 AM

Thanks to all the much-appreciated info and advice, I read the related threads, watched youtube on installing a cutoff switch, ordered mini toggle switches from ebay (I don't do Amazon bc monopoly = not a good thing), drove up to my TT on job site, and discovered this miracle:

I'm one lucky bloke, with a couple of spare mini toggle switches!

**JRTJH** · 10-31-2022, 08:47 AM

Quote:

Originally Posted by Eggs Benedict

Thanks to all the much-appreciated info and advice, I read the related threads, watched youtube on installing a cutoff switch, ordered mini toggle switches from ebay (I don't do Amazon bc monopoly = not a good thing), drove up to my TT on job site, and discovered this miracle:

I'm one lucky bloke, with a couple of spare mini toggle switches!

Fortunate for sure....

Now, the question becomes: With that switch turned off, what the the "watt draw" on your battery? There will likely still be the LPG detector, the refrigerator control board and the radio memory circuits. Thinking back to the 2007 era, I don't know of anything else that would have been an OEM battery drain.

Eggs Benedict · 10-31-2022, 10:41 AM

Quote:

Originally Posted by JRTJH

Fortunate for sure....

Now, the question becomes: With that switch turned off, what the the "watt draw" on your battery? There will likely still be the LPG detector, the refrigerator control board and the radio memory circuits. Thinking back to the 2007 era, I don't know of anything else that would have been an OEM battery drain.

Ah - forgot to mention that with the switch off, the watt draw is so low it registers as 0 on the Bluetti power station. I have all other draw (not the refrigerator) shut off at the breakers when not in use. Very helpful for getting through the charge/discharge day relying only on solar. I still have some solar charging issues to sort out, but this was a major improvement.

WDPatterson · 10-31-2022, 11:49 AM

Quote:

Originally Posted by Eggs Benedict

Ah - forgot to mention that with the switch off, the watt draw is so low it registers as 0 on the Bluetti power station. I have all other draw (not the refrigerator) shut off at the breakers when not in use. Very helpful for getting through the charge/discharge day relying only on solar. I still have some solar charging issues to sort out, but this was a major improvement.

Not sure what your goal is here, if 47 watts is an issue. If you have zero draw, and that's your desired goal, that means you can't run anything at all.

BigBobIa · 11-01-2022, 08:13 AM

Quote:

Originally Posted by Eggs Benedict

I have all other draw (not the refrigerator) shut off at the breakers when not in use.

Do you mean you are pulling all the fuses? The breakers are 110v and have nothing to do with battery drain.

WDPatterson · 11-02-2022, 10:58 AM

Quote:

Originally Posted by Eggs Benedict

Thanks to all the much-appreciated info and advice, I read the related threads, watched youtube on installing a cutoff switch, ordered mini toggle switches from ebay (I don't do Amazon bc monopoly = not a good thing), drove up to my TT on job site, and discovered this miracle:

I'm one lucky bloke, with a couple of spare mini toggle switches!

That's cool solution!.. reminds you of a switch they had on the home refrigerators a a few years back. It basically shuts off the frost-free setting on home fridges.
As others have mentioned, that switch disables the heater pad that is located in the refrigerator and freezer doors, and the sidewalls of the cabinet.
I have no idea how yours is specifically configured, but keep in mind that you're going to get droplets of condensation at some point. The good news is, you can turn that back on anytime you want.
If you want to run that refrigerator full-time, you going to want to expand the elements in your system that generate the power. If you want to stay off grid, you're going to want more panels. I can't emphasize this enough.

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