Driving on 12V ( & compression fridges)

[JPerodie]

Sorry if this is a repetitive post. I've read many posts about driving on 12V, trying to to improve my understanding. I've put what I think I've learned into my own words. Could someone please let me know if I'm correct:

- if I run my fridge on 12-volt while driving, the trailer batteries power the fridge. The trailer batteries will likely drain, my truck will probably not keep the trailer batteries adequately charged.

- if I have a compression fridge which draws 5 amps, and dual 6 volt batteries, I can drive all day without running out of battery power. If my stop for the night has hookups, my batteries will recharge overnight.

- if I drive in sun, my current roof mounted 160 W panel that puts out 10 amps will likely keep my batteries mostly charged. If I add a 200 watt panel to the roof I may get 20 amps total in full sun and also be good.

- if I want to camp without hookups, with my 5 amp compression fridge, dual 6V, and I'm not getting good charge from my rooftop solar panels, I'll probably run out of battery in less than 2 days. I could extend that by adding more battery power, and portable solar panels .

- also, I should use an isolator switch in my truck to break the battery to battery connection when I'm stopped.

Is that more or less correct?

Thanks

[cpaharley2008]

Just use propane to cool while traveling, silent and dependable and you have 2 large tanks for fuel.

[Chamberman]

I think you've mixed Absorption fridge questions with Compressor fridge questions and you have not differentiated this in your post. This makes your post very confusing especially given the title of your post. After reading your post several times it appears that Questions #1 & 3 are absorption fridge questions but you do not state that.

[cpaharley2008]

Sorry, I thought you had stock 3 way cooling. If 12v is you only option then I think you answered your question.

[Vermilye]

Your assumption of 10 amps for a 100 watt panel & 20 amps for 200 watts is highly optimistic. 6 amps & 12 amps under ideal conditions (overhead sun with no clouds, and cool temperatures) is more likely.

I agree with assumptions 1, 2 &4.

As to the trailer disconnect - check to see if your tow vehicle already has one. If not, adding an isolation relay is the best way since you don't need to remember to shut it off.

[JPerodie]

Originally Posted by Chamberman

I think you've mixed Absorption fridge questions with Compressor fridge questions and you have not differentiated this in your post. This makes your post very confusing especially given the title of your post. After reading your post several times it appears that Questions #1 & 3 are absorption fridge questions but you do not state that.

Ah, yes, I can see that it could be more clear. I don't see an edit button, perhaps because I'm on my phone.

[JPerodie]

Originally Posted by cpaharley2008

Sorry, I thought you had stock 3 way cooling. If 12v is you only option then I think you answered your question.

Thanks for replying. Yes, as noted, I could have been more clear. I currently have a 3 way RMD 8555 which I operate on propane when driving. I'm tiring of its lackluster performance.

[JPerodie]

Originally Posted by Vermilye

Your assumption of 10 amps for a 100 watt panel & 20 amps for 200 watts is highly optimistic. 6 amps & 12 amps under ideal conditions (overhead sun with no clouds, and cool temperatures) is more likely.

I agree with assumptions 1, 2 &4.

As to the trailer disconnect - check to see if your tow vehicle already has one. If not, adding an isolation relay is the best way since you don't need to remember to shut it off.

Thanks for replying. I admit I've never tested the amps coming from my 160 W panel. Reace tested it after installing, and said it was getting"nearly 10 amps"..... I rounded up. I speculated that I might get 20 amps from a total of 360 W panels in full sun.

[cpaharley2008]

Originally Posted by JPerodie

Thanks for replying. Yes, as noted, I could have been more clear. I currently have a 3 way RMD 8555 which I operate on propane when driving. I'm tiring of its lackluster performance.

I always had good luck with the "propane" cooling. Perhaps a refer tune up can help?

[Jwinfrey]

One other thing to consider is that the Compressor fridge only runs about 50% of the time. 5 amp/hr draw is really 2-3.

[JPerodie]

Originally Posted by cpaharley2008

I always had good luck with the "propane" cooling. Perhaps a refer tune up can help?

That's a good tip, thank you. Although it seems like the fridge's performance has been consistent over the years. Like others experience, it struggles in hot weather, and we prefer camping in the hottest weather we can. We've done several work arounds with the fridge, still not that pleased.
I'm curious about compression "fridging", trying to learn.

[Chris R]

Originally Posted by JPerodie

Thanks for replying. Yes, as noted, I could have been more clear. I currently have a 3 way RMD 8555 which I operate on propane when driving. I'm tiring of its lackluster performance.

As you say, the RMD8555 ( I have one) has lackluster performance which can be improved by properly insulating the fridge cavity in the trailer. I also suspect the baffle behind the fridge is not up to Dometic's fridge specs so hot air removal is compromised. There are several threads in the forum detailing how improvement can be made to the fridge cavity.

https://www.escapeforum.org/forums/f...ade-20473.html

[JPerodie]

Originally Posted by Jwinfrey

One other thing to consider is that the Compressor fridge only runs about 50% of the time. 5 amp/hr draw is really 2-3.

Thank you.

[JPerodie]

Originally Posted by Chris R

As you say, the RMD8555 ( I have one) has lackluster performance which can be improved by properly insulating the fridge cavity in the trailer. I also suspect the baffle behind the fridge is not up to Dometic's fridge specs so hot air removal is compromised. There are several threads in the forum detailing how improvement can be made to the fridge cavity.

https://www.escapeforum.org/forums/f...ade-20473.html

Thanks for the link!

[JPerodie]

Originally Posted by Chris R

As you say, the RMD8555 ( I have one) has lackluster performance which can be improved by properly insulating the fridge cavity in the trailer. I also suspect the baffle behind the fridge is not up to Dometic's fridge specs so hot air removal is compromised. There are several threads in the forum detailing how improvement can be made to the fridge cavity.

https://www.escapeforum.org/forums/f...ade-20473.html

I have to admit that I've always been intimidated by the idea of pulling the fridge out. The mass of wires and pipes in the exterior hatch which must have to be disconnected somehow and then reconnected seems daunting. But maybe I'll have to try.

[Chris R]

Originally Posted by JPerodie

I have to admit that I've always been intimidated by the idea of pulling the fridge out. The mass of wires and pipes in the exterior hatch which must have to be disconnected somehow and then reconnected seems daunting. But maybe I'll have to try.

It's not that bad, at the back, one plug, two wires and unscrew the propane (after the tanks are turned off) and a bit of spray foam at the bottom. At the front, four screws.

Because I was doing it myself, I made a temporary stand at the same height as the bottom of the fridge so I could slide the fridge out, no lifting. I did remove the three trim pieces around the front of the fridge to avoid damage to them when pulling the fridge.

Tip, take photo of the wires before so you have a reference when putting them back.

[JPerodie]

Originally Posted by Chris R

It's not that bad, at the back, one plug, two wires and unscrew the propane (after the tanks are turned off) and a bit of spray foam at the bottom. At the front, four screws.

Because I was doing it myself, I made a temporary stand at the same height as the bottom of the fridge so I could slide the fridge out, no lifting. I did remove the three trim pieces around the front of the fridge to avoid damage to them when pulling the fridge.

Tip, take photo of the wires before so you have a reference when putting them back.

Ok, thank you. I'll refer to this should I get the nerve.

[cpaharley2008]

If I lived in Vancouver, I would return to Chilliwack for repairs........

[Brian B-P]

Originally Posted by JPerodie

I don't see an edit button, perhaps because I'm on my phone.

After a period of time, edits are no longer allowed so the edit button does not appear. All you can do is make a new post to provide the clarification, perhaps replying to your own message for context.

[JPerodie]

Originally Posted by Brian B-P

After a period of time, edits are no longer allowed so the edit button does not appear. All you can do is make a new post to provide the clarification, perhaps replying to your own message for context.

Thank you.