Trouble powering Dometic fridge with my little guy camper

[immped64]

This week I am camping at a campground near me and my solar/battery combo is not working to what I know it should be capable of.

Quite a few years back I installed a Renogy Rover Solar system on my trailer. [url]https://www.amazon.com/gp/product/B07CTGJ13D/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1/url]
This seemed to operate soundly even though a family difficulty prevented me being able to break free for camping for several years, so I never had the chance to fully test this out.

Prior to my "upgrade" I was able to get around 3 days of cooling on my Dometic mini refrigerator. [url]https://www.amazon.com/gp/legacy/order-history?opt=ab&search=dometic&_encoding=UTF8&ref_=ppx_yo2ov_dt_b_search/url]

I was hoping to stretch this out to a week.

This week was the beginning of my 1st camping trip with my 3 year old Golden Retriever. I have been having a mixture of good and not so good experiences. What troubles me the most is that I got less than a day on my mini refrigerator before it completely cut out.

Prior to heading out I had been doing some testing in which I also was seeing some disappointing results. On my 20 amp renogy rover charge controller [url]https://www.renogy.com/content/files/Manuals/RNG-CTRL-RVR2040_V1.0.pdf?srsltid=AfmBOorC3ehdKmURPCkqbMUy0UudsZyjK-sgKl5SAwOdfFEFuDSNJdpL/url] I at 1st wasn't seeing the 3rd LED light actually light up until I discovered that I needed to hit the right button to activate the load. I thought that this might solve the problem as all the LED lights seemed to show up as they should. Obviously it did not.

I have had a lead acid deep cycle battery for several years. I know absolutely nothing about what the voltages should be reading beyond that they shouldn't read under 12 volts. I have taken multi meter readings of the battery as it was detached from the load (toggling the right button back again). It read 12.8. During the day as it was carrying the charge it read around 13.4 volts. After the refrigerator faded out the reading at the battery was 12.9.

A day prior to my camping trip I went to Tractor Supply and ended up buying an AGM battery (instead of my lead acid battery type) which was capable of 70 Amp Hours. [url]https://www.tractorsupply.com/tsc/product/traveller-auto-battery-ib-h6agm/url] When I got home I measured the voltage. Even after applying a charge to the battery it read only 12.55 volts which I am assuming might not be capable of carrying the load as my lead acid battery reads 12.8 without solar load. Then another question hit me in regards to this battery; when reading the Renogy manual it states "Use only sealed lead-acid, flooded, or gel batteries which must be deep cycle." There is nothing on the AGM battery itself that states that it is a deep cycle battery. This makes me think that I flat out made a bad purchase. Then I read somewhere else online that any AGM battery will work with a Renogy charge controller??? Tell me this is a step backwards and I can see about getting an exchange for this specific battery. Any other advice here?

Could I discover any other indication in why my existing battery doesn't work correctly in conjunction with my Renogy solar install?

The Dometic refrigerator works fine when I run it through a AC to DC converter. The refrigerator also runs fine when I run it with my Jackery portable power station. I don't know how far this might stretch me along but I could just try running the fridge with portable power.

I don't get any error codes with my Renogy solar install, but could there be something that is inefficient as it is leaving the battery box and where might I measure this with my multi meter?

[TimC]

I really don't know where to start with advice. Solar has so many variables that a simple answer is not going to address the problem. I'm not a 12V or solar expert but I have some experience with both and a 12V fridge.

Your 70 aHr AGM battery is at most good for 35 aHr unless you want to take its life early. Don't' run your battery down under 12.1 volts. My refrigerator, a 32 quart Alpicool is very efficient. It used about 14 aHr per day when I tested it after installing it. That was a 48 hour period where the day temps were around 70 degrees and night down to about 55 degrees. At 35 aHr that AGM battery will power my fridge for about 2.5 days if I don't run anything else (rare). If you are in a very warm climate your fridge would not do that well. If you are constantly opening it it won't do as well. If you are putting warm items in it and expecting it to cool efficiently you will be disappointed. I'm assuming with the link you provided you only have a 100 watt panel. That is a little light for recovering each day if you get 100% sun for six to eight hours/day. 100 watt panels typically will only get about 80% of that rating in "normal" use, and only during mid-day. It may be rated at 100 watts, however, that is in lab testing under the perfect temperature and sunlight conditions. 200 watts would recharge your system quicker.

Also, your AGM is an "Absorbed Glass Mat" battery which is basically a gel battery and should work well for "deep cycling". But not deeper than 12.1 volts.

So I would suggest you get one of these ammeters and test the actual energy use of the fridge. There are other types of ammeter that might work for you.



Bottom line is this... your Renogy Rover is a good unit with MPPT charging technology. I don't think that is limiting your charging. You should be able to add another 100 watt panel to your system but make sure you don't exceed the amp rating of the Rover. How your solar panel is pointed through the day is a big deal. If it is pointed in the wrong direction for part of the day, in other words, not ideally pointed to the sun, it will not charge your system quickly. If you are running other loads you will be effecting the capacity as well. A second or third battery, or a larger battery would help. With today's electronics power demands you must conserve power when you are charging those items. For instance, I don't charge my phone/flashlights/etc. at night. I only charge when the sun is charging my system. That's unthinkable for some folks who are attached to their phones like a tumor in their palm.

[immped64]

I am very frustrated. I had a long reply to you and when I hit send it wanted me to log in again and the message was lost.

Since I am still camping I had better delay my full reply.

In the interim I have a couple questions to ask. I am using a lead acid battery right now which at no charge registers 12.6 volts. Earlier this week I purchased an AGM battery which after I charged it registered a reading of 12.55 volts. Would there be any reason for me to keep this battery for the purpose of powering my refrigerator? Are there any numbers on a specific AGM battery that I should be looking at to have a better chance of success?

I will look into the refrigerator watt power tester that you have suggested.

[immped64]

I have been looking at the Watt Power Tester and some of its equivalents as I do want to find what voltage is getting through to the dometic refrigerator. I really didn't see anything that appears capable of doing this and even if I was to get my multimeter probes in to the socket it likely would cause a short circuit. If there was a viable way of testing this I would certainly like to see how much current loss I am getting.

Tim: I believe what you were suggesting instead of the current getting to the cigarette lighter socket was to test the running current used with the refrigerator's operation. I am assuming that the only way to use the shown tester would be to split the dometic power cable in 2 and twist and solder the connections to allow this inline display to be read properly.

I know that this is something that is commonly done, but I don't know whether I would trust my wire connection skills to permanently stay in place. There always would be a weak point that if the fridge was pulled out of the camper without disconnecting it could break apart the wire connections. I don't know whether the benefit would out weigh the potential downside.

In reading refrigerator testing forums I have heard another option which is a "kill a watt" current tester. The only thing is, I don't know how this might be used with DC instead of AC power.

I did a little research on how far 70 Amp hours would take me with the dometic refrigerator's rated 3.1 amps and did decide to bring back the AGM battery. After a lot of deliberation I ordered a 100 amp hour lithium battery; knowing the temperature related short comings that it has. I am doing the teardrop camping as a hobby and not having to spend large stretches of time in it so I believe that this might be a hopeful solution.

[TimC]

I have been looking at the Watt Power Tester and some of its equivalents as I do want to find what voltage is getting through to the dometic refrigerator. ...

Did you mean to say what amperage is getting to the fridge?

Tim: I believe what you were suggesting instead of the current getting to the cigarette lighter socket was to test the running current used with the refrigerator's operation. I am assuming that the only way to use the shown tester would be to split the dometic power cable in 2 and twist and solder the connections to allow this inline display to be read properly.

Not the only way, but, correct. If you install the ammeter inline at the fridge you will be able to monitor amps, watts and kilowatt hours. Simple math... to convert the kWh to aHr you divide the kWh reading on the ammeter by the voltage of the source, your battery's voltage. That will tell you the aHr's used. You should use 13.3, or thereabouts, for the voltage if you are using your new LiFePo4 battery. If using a SLA battery use 12.3 volts (or thereabouts).

I know that this is something that is commonly done, but I don't know whether I would trust my wire connection skills to permanently stay in place. There always would be a weak point that if the fridge was pulled out of the camper without disconnecting it could break apart the wire connections. I don't know whether the benefit would out weigh the potential downside.

I am going to go out on a limb and say that your wire termination skills will produce a better connection than any 12v cigarette lighter socket. On my first trip with my first TD the plug vibrated out of the socket repeatedly. To the point every time I stopped I had to plug it back in.

In reading refrigerator testing forums I have heard another option which is a "kill a watt" current tester. The only thing is, I don't know how this might be used with DC instead of AC power.

The Kill-a-watt I have is for 110 volts only. A 12 volt ammeter is going to do the same thing, sort of.

I did a little research on how far 70 Amp hours would take me with the dometic refrigerator's rated 3.1 amps and did decide to bring back the AGM battery. After a lot of deliberation I ordered a 100 amp hour lithium battery; knowing the temperature related short comings that it has. I am doing the teardrop camping as a hobby and not having to spend large stretches of time in it so I believe that this might be a hopeful solution.

That will be an improvement. It will give you more reserve capacity. Just do some preplanning before you head out. Precool your fridge on 110 volt at home. Put cold items in the fridge, at home.
Charge your electronics during the day when the sun is shining on your panel. Conserve energy when you can. If you buy a six or twelve pack during your stay do not put it in your fridge unless it is cold.

It's all common sense stuff. Think about energy usage before and during every trip. Maybe that's a PITA but it will become routine and easy after a while.

I'll PM you on tnttt and give you another suggestion or two about how to "hard wire" your fridge for easy removal.

Tim

[immped64]

Tim: Thank you for your replies. This gives me a better idea of what to expect. I think that I will try out the new battery when it arrives and see if this helps me to achieve what I'm looking for. If not; then it would be good for me to see what the actual "amp" draw is. It's too bad that they don't sell something that you could just plug into the DC socket and plug the other end into another socket that comes from the refrigerator.

That is a great idea in pre-cooling the refrigerator prior to a camping trip. Normally I'm cautious on opening the fridge too often but it would be great to give it a good start.

[TimC]

You could build your own cigarette lighter adapter if the need arises. Cut the extension cord (below) in half, wire the ends to the ammeter and away you go. The only other item is four blue butt splices.


https://www.amazon.com/LoveDeal-Precisi ... 6109ace758

And

https://www.amazon.com/Cigarette-Lighte ... 725&sr=8-6