Why is LP fridge pulling 47 watts?

[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!

[JRTJH]

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]

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]

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.

[firestation12]

I was curious to know what type of batteries you have that total 200ah. FLA (flooded lead acid 6 volt golf cart or 12 volt deep cycle), AGM (absorbed glass mat), or LiP04 (lithium). Each type has a different usable amp hour from the amp hour claimed, as well as different charging characteristics. This might be one of the reasons you are having problems fully charging the batteries from your solar panels.

[WDPatterson]

Originally Posted by firestation12

I was curious to know what type of batteries you have that total 200ah. FLA (flooded lead acid 6 volt golf cart or 12 volt deep cycle), AGM (absorbed glass mat), or LiP04 (lithium). Each type has a different usable amp hour from the amp hour claimed, as well as different charging characteristics. This might be one of the reasons you are having problems fully charging the batteries from your solar panels.

That's an excellent question. Different types of batteries, different chemistries, have different charge/discharge profiles which effect the overall performance and usability of the system.

[BigBobIa]

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.

[Old_Stevenick]

For those of you that think 47 watts is negligible. That's almost 4 amps. Times 24 hours per day, that's 96 amp hours. That's a lot.

My fridge draws about 8 watts when on Propane which is still 16 amp hours per day.

I think the door heater would be probably 6 of those watts, so disabling it would be 12 amp hours per day.

Not negligible particularly if you're boondocking on lead acid batteries.

[WDPatterson]

Originally Posted by Old_Stevenick

For those of you that think 47 watts is negligible. That's almost 4 amps. Times 24 hours per day, that's 96 amp hours. That's a lot.

My fridge draws about 8 watts when on Propane which is still 16 amp hours per day.

I think the door heater would be probably 6 of those watts, so disabling it would be 12 amp hours per day.

Not negligible particularly if you're boondocking on lead acid batteries.

If you have lead acid batteries, and you think you have 200 amp-hours, you don't. Lead acid batteries do not last if you go below 50%. Get away from lead- acid batteries, go to lithium iron phosphate batteries.
With lithium iron phosphate batteries, you can go down to 20%, and still recover very well. You can go to zero, and take a slight hit. But, lead-acid batteries will destroy themselves below 50%. That's not even taking into account cold temperatures.

47 Watts is 47 Watts.
200amp hours, at 12 volts, is 2400 watt hours.
It's Watts that do the work. Amps is just a measure of flow.

If you want to do some math, use this:
https://footprinthero.com/amp-hours-...urs-calculator

[Old_Stevenick]

Yes I know, I do have two 100 ah LifePO4 batteries, I was just pointing out how much 47 watts were if you did have Lead Acid batteries.

As far as my math is concerned I said the same thing as you.

8 watts is .75 amps at 12 Volts.

Times 24 hours is 192 watt hours or 16 amp hours.


With a 12 volt system you just divide the watts by 12 to get the amps and multiply by the number of hours you expect the device to be on to get the Amp Hours.

[WDPatterson]

Originally Posted by Old_Stevenick

Yes I know, I do have two 100 ah LifePO4 batteries, I was just pointing out how much 47 watts were if you did have Lead Acid batteries.

As far as my math is concerned I said the same thing as you.

8 watts is .75 amps at 12 Volts.

Times 24 hours is 192 watt hours or 16 amp hours.


With a 12 volt system you just divide the watts by 12 to get the amps and multiply by the number of hours you expect the device to be on to get the Amp Hours.

Those are not the same numbers you posted earlier. Do the math properly, use proper equipment, and be sure that you are correct. Get off of lead acid batteries, they're not helping you. If you're only using 175 Watts worth of panels, you're going to need more panels.
These days, everybody is looking at the long-term. A short two or three day binge in the boonies is still going to require more.
I've been shaking my head for the last 8 years at the way RV dealers sell solar kits on trailers. It's not enough, it barely runs a residential fridge. That's their selling point.
Look around, get some good panels and a good charge controller, and think like you're going to be there for a while.

[Old_Stevenick]

I am not the OP, I don't have solar, I don't have lead acid, and AFAIK my math was correct.

[WDPatterson]

Originally Posted by Old_Stevenick

I am not the OP, I don't have solar, I don't have lead acid, and AFAIK my math was correct.

Your last two comments were as though you had solar, and batteries.
Might be good to have a pony, if you're going to join the race.

The bottom line is this:
• If you're worried about 47w, get more (or bigger) panels. The roof of your RV is big enough to handle at least one 400-plus watt panel.
• Get away from lead acid batteries, if you're using them. Lithium iron phosphate batteries have become less expensive, and are a good investment.
• Don't go cheap, you only spend the money once.
• Look to the Future when you buy. Everything changes, you know you're going to be expanding your use. Plan for more panels and more batteries. That means choose a charge controller that can handle a bigger load.
• If you're going to buy a minimal inverter, think about what else you can use it on when you have to get a larger inverter. Otherwise, buy a bigger inverter.
• I cannot emphasize this enough:
Think Ahead.

[Old_Stevenick]

Actually my posts don't say anything of the sort, but others do. Look at who wrote things before criticizing what people are saying would be my advice to you.

My pony in this race is a lot of knowledge about battery draw when boondocking.

[WDPatterson]

Originally Posted by Old_Stevenick

Actually my posts don't say anything of the sort, but others do. Look at who wrote things before criticizing what people are saying would be my advice to you.

My pony in this race is a lot of knowledge about battery draw when boondocking.

Everybody here has boondocked and has battery draw. That's not the solution. That's the problem stated.
The advice needed has to do with solar energy, it's configuration, and the results required. The guy is asking about his wattage draw, but he doesn't have the solution at hand. If you're not the solution at hand, you may want to watch.

Actually, you know that's not fair of me. The guy was mentioning that he has a 47 watt draw, and he wasn't sure where it was coming from, and he wants to go to zero draw. That pretty much means that he wants to shut everything off so that his 175 watt panel can top off his batteries and keep them that way.
That part, I can understand. However, expecting the fridge to run on 175 watt panel on a cloudy day would be futile. That is MY point.

Let's also keep in mind that every time that fridge has to ignite that burner for the propane flame to heat the ammonium coils, it's going to require some power. Do you know what that igniter is drawing? Does it really matter?

Again, you need more solar power if you want to play that game. Buy a bigger panel, solve the problem without any complication.

[Old_Stevenick]

First time I’ve been told to shut up on this forum. Question? Is there a way to ignore a member here?

[WDPatterson]

Originally Posted by Old_Stevenick

First time I’ve been told to shut up on this forum. Question? Is there a way to ignore a member here?

You didn't get told to shut up. You just don't agree with my answer. Say what you want, I don't care. The point is, the guy is asking for advice. What I said is still true.

By the way, you have two Good batteries to run your fridge anyway you like 24 hours a day. If you add solar panels and a charge controller, you can keep on doing that without ever having to put an external charger on the system.

[WDPatterson]

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.

[Fourbtgait]

Originally Posted by JRTJH

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".

Every year I tell my wife there is nothing left to do on the trailer. But yes, this is an important one to take care of. We dry camp with partial solar 95% of the time. I realized we had a big drop in a 24 hour period, but not until this post realized why.
It is post’s like this and the knowledge shared that makes staying on website nice.

Thanks for the information.

[GoingPlaces]

Can anyone tell me if the Dometic DM2872 refrigerator has this "Low Ambient Climate Control System" ? I've scoured the manual and no mention of it. Also sent Dometic Customer Service an email last week and have not heard back (yet).

This might help explain some of my overnight voltage drop with nothing much in operation.

I have not pulled apart the light fixture yet to see if there are two neutral wires near the bulb.

BTW this model uses a LED bulb.

This looks like a quick cheap little project which could save a few precious watts.

-Thanks