Fridge Power

nabcracker

New member
I have a Ram 2500 with Snugtop shell to pull our Outdoors RV Back Country 24 RDS. The bed of truck is devoted to carrying our ARB Elements fridge and our two hounds. I am debating two power options for the fridge currently to best suit our use and provide reliable power for fridge. Our main cold storage will be propane fridge in camper, but I like having the ARB for day trips and back up food storage when camping off grid. I am not so concerned with the cost difference between the two systems and if I had the time I would most likely do option 1 so I could expand the system to include on board air and rewiring of my winch to battery bank. Option two is in the running due to my lack of free time to install option one. For use, over a 3-4 month trip we would be spending 2-3 day in one spot between longer drives. During the 2-3 day stays, we will do some driving but not all day driving. I intend to buy a portable 150w or so solar panel to supplement the 170w mounted on my camper and to top up truck if needed. My question is, would I be asking to much of the Dometic PLB40 set up during full time use? In the long term, we plan to add RTT to truck rig so we can have the option for farther off grid camping than we can reach with the RV, so the ARB would eventually see heavier use.

1. Go full blown 100Ah LifePO4 battery with DC/DC charger (REDARC BMS 30) and power outlets for fridge. (Or some variation of this)
2. Dometic PLB40 and 7 pin trailer plug adapter to cigarette plug
 

Chorky

Observer
I think your asking too much. As I have found out myself. I suppose it depends on if your fridge stays on all the time, and if you have abilities to plug into a shore power somewhere or not. So my RV fridge is a POS. So I ended up getting a snowmaster LP67 (66 maybe?). Anyway, I 'tested' it hooking it up to my 21' trailer, that I live in full time for over 3 years now. Went boondocking for 4 days. Half way through the 3rd day (and the first day was 5 hours of driving - so really only the 2nd day of actually off grid), my dual 6v batteries were drained to the point where the fridge 10.something auto shut-off engagged. In other words, I had to start my genset and let it charge the batteries for about 4 hours - only got them up to 75% charged. Now, I could have bad batteries - not likely, or a bad connection - more likely. But point is, I think people generally are expecting more than reality would have it for battery powered fridges. A propane one has its own huge problems... Like, not even getting down to temps. But at least a propane bottle will last a much longer time. I'm contemplating at this point if I want to go elec. or propane for a custom trailer build if that means anything. Also, I was not hardly using any other trailer features (lights rarely, water pump only to flush and wash hands). So there was very little drain outside the fridge. Hope my experience helps - keep in mindI could have some other sort of problem going on.

By the way, how do you like your trailer????
 

john61ct

Adventurer
First off, propane fridge will not run off offgrid electric ever right?

A 40Ah battery will rarely be enough, even if LI chemistry, to keep even a super efficient compressor fridge going, except in ideal conditions, low ambient temps, high thermostat settings and high insolation conditions all lining up.

I usually recommend at least 150Ah of storage, maybe 200Ah to handle 2-3 cloudy days in a row.

200+W of solar also, but frequent driving/ alternator input can reduce that.
 

Chorky

Observer
Actually, a propane fridge will run 'off grid' for a long time. It still requires a 12v source to run the circuit board, but pulls very very little power since it is using propane for a heat source, in relation to a 12v compressor fridge - my trailer's propane I think pulls only 2a on gas, but the 12v pulls something like 7.5a. Big difference.... A propane fridge with 2 6v's can easily last a week. The problem is that the standard RV industry propane fridges also have major flaws, and have a difficult time keeping internal temps down to what a fridge should be. At least thats the case I have experienced, and my neighbor happens to be a RV tech, and said that's pretty much the norm, as wrong as that sounds... So it's a catch 22 really. A compromise - a propane fridge will last longer than a 12v compressor fridge 'off grid'; however, a 12v compressor fridge will actually get to appropriate temps....

Now some issues I find with battery power, is in theory you are correct about the amount of 'power' storage you need. But that's assuming that after 3 days you have the abilities to fully charge those batteries and/or those solar panels are putting out their max potential. The reality is 1) only having a hookup will actually do that - or running a genset for an entire freaking day (lots of gas), 2) I find it's actually a rarity that solar panels put out as much as desired even though they are still an excellent way to go, and 3) its just not practical unless your only doing 2-3 day trips, in my opinion. I am finding out, that the guys who are using monster trucks (think MAN) for world expeditions have massive battery banks, but still have to charge them via shore power somehow some way, or a genset, every several days depending on how long they stay somewhere. So I think though theory works, the realities are that its not really very practical unless you have a significantly larger battery bank. The other thing to consider that I find is what other items will you have running? Even something as simple as a couple lights, or a 12v water pump can put your 12v fridge below the auto-shutoff threshold. And thats not mentioning how much power you need to reserve for starting the truck. In this instance, though not everyone does it, I personally would find it a necessity to have batteries running the fridge or any other 'house' item to be isolated from the main vehicle batteries, except for when driving/charging.

Now I'm no expert, but these are things I have found out and experienced that have turned me away from a vehicle mounted 'house' (ie a camper) and steered me more toward a reasonably sized (21-26') trailer. That way you can still, say, have a small 12v fridge in the truck that only runs to keep lunch and beverages cool, but the trailer can have the capacity for a genset and a very large battery bank since that would be some pretty significant weight. But even then, the more I look into the real world power requirements of a 12v fridge, and considering I'm full-time, I honestly must say that a propane fridge, even though fragile, is looking to be pretty darn enticing, if only to keep the weight of batteries down. The last thing I'll mention now is the consideration of cost. Sure propane costs a fair amount. But 4 30# tanks can last a good while depending on other uses. But to get a battery bank that could last a significant amount of 'off grid' time in the dead of winter (I live in Montana), your talking about some massive battery banks, and those suckers are super heavy and expensive!

If only someone made a diesel fridge!!!!! I think in the end it may depend heavily on your own personal use or expected use. If you just want a couple day camping trip, then 12v is probably just fine. But if you live full time in your rig, and want to keep things running to keep food good when away for weeks at a time due to work (like me), or to even simply just boondock for a good long while, then battery power without some sort of shore charging or a genset every few days is going to be pretty darn difficult.

But back to the OP - since your staying in your trailer, and primarily using your propane fridge, and really just using the ARB for day trips to keep lunch cool, you might just need one extra battery in the truck to support the fridge for the few hours your out hiking or doing what-ever, so that you dont draw down the truck batteries. Then you could charge that when returning to the trailer with either shore or a genset to top it off, since driving likely wont charge it fully in itself.
 
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nabcracker

New member
Thanks for the input - having suffered loss of cooling on both 2 way rv fridges and 12V coolers, I am trying to find a solid approach to keep the beer and steaks cold if the RV fridge freaks out. Realistically, on extended trips we will be pulling into campgrounds with power and water every 4-5 days to do laundry and let the family have longer showers, so we can recharge and manage tanks at these stops. I am thinking the 100Ah house battery (option 1) will be the starting point for truck bed but plan for adding more Ah if needed.

Corky - we are really liking the trailer. After owning numerous Jaycos from hummingbird to 5th wheel and giving up RTT camping, this unit seems to fit all our needs and is built solid. It provides the comfort and security we want with small kids but lets us stay out of proper campgrounds for most nights.
 

Chorky

Observer
I totally understand your dilema!!! I'm there now and have been for the last 2 years. So heres my specific experience if it may help you any...

I have a cheapie trailer - 2011 Springdale 179QB. About the only good thing about it was the price, the condition upon purchase (used) and the suburban water heater. So my fridge started failing on and off at a year of purchase, and a year of full time use. Nobody knows why... it just randomly fails. Sometimes it wont cool properly. Even when it 'works' it doesn't cool to the FDA specs of 34-40 for the fridge, and below 0 for the freezer. I think the freezer barely gets to a few degrees above zero at it's best - usually in the middle of the night. So, after 3 times of loosing an entire fridge of food (ie, would come back from a weekend day trip to everything spoiled and fridge temp same as outside ambient temp) I got pissed enough to research and buy a 12v fridge. So I'm using the LP67 snowmaster now full time for the last 2 years. Even it has had 2 instances of just randomly shutting off, for no reason I can find. But it has the benefit of being able to actually set temps between the two storage compartments reasonably different. The fridge portion actually stays around 34, while the freezer stays around -5. Anywhoo, I have confirmed via my own testing, that with 2 new 6v batteries, I can only run the fridge, and various amounts of other minor things truly off grid for 2 full days. So at least I have enough to keep food ok for a weekend, or during a power outage until I get the genset going or plug in. But, that is pale in comparison to what 'theory' states, and to what other people and manufacturers say. Now, before the gas side of the fridge stopped working (again, no known reason, and the trailer is in good condition, its not some white trash junk), I was able to run on gas for, well, as long as I wanted really within respect to how long I would be out of power, at the cost of not being truly within refrigeration temperatures. I'm stationary since I'm full time - but I did have 2 weeks of power outage once back in Washington, and never had a problem with the fridge until the gas no longer worked. So, i have gone back and forth myself about what system is better, and really, it seems they are both on par, with only having different positive points and different negative points. Which is why I say it's really dependent on what your plan is. It's pretty sad to me either way that this is the case, especially when the technology is there to make it better.

So if your mostly going to be able to have shore power every few days, then a small fridge for lunch stuff and a battery specific for that fridge (or other things like maybe a water pump or air compressor) in the truck probably would be just fine, especially if you had a solar attached to it also. I suppose my original input was for considering significantly longer times away from a solid charging ability. But you could easily charge it at the campground or via a genset on the trailer.



That's cool you like your trailer! And even better getting the kids out and experienced early! 🍻 My folks just picked up one too, it's a 31' version and they love it minus having a few problems already. I have considered one, but think it would be better to build my own considering the cost of those things. They are on the higher end of quality for available trailers though!!
 

Chorky

Observer
Its been done already. I have one. Technically, its supposed to use kerosene, since I keep it under my shed roof, it uses diesel and outdoors stink is no problem.
They are common in thirdworld and special belief communities.
ooo can you PM me some details?? don't want to highjack this thread.
 

john61ct

Adventurer
There are excellent propane fridges, even freezers, but definitely not from the RV industry, more for off-grid homes and not cheap.

I lived for thirty years using propane fridges in outback Australia, no electricty at all required.

Early days they were conversions from old-school kero fridges, any heat source would work just fine long as it's slow & steady 24*7.

To be sure of having enough solar-only power for a 12V DC compressor fridge, even a big one in very hot ambients and lots of cloudy days or far from the equator

400W solar and a 200Ah bank should be enough.

But running it as a freezer might be cutting it a bit close, add 50% to both.
 

Ducky's Dad

Explorer
Depending on how your truck came from the factory, you might consider upgrading the alternator. My Power Wagon came with 160amp alt, and I thought it was great until I added a fridge and a second battery to support it. Wound up adding a second house battery to give me 150ah in the house bank plus 105ah in starting battery, plus a 270amp alt. Still not enough in the desert in summer temps. FWIW, the Warn winch on the PW draws 440 amps at max pull, rated at 12,000 pounds but is mostly 15,000 pound components. You will need way more juice than you think.
 

67cj5

Man On a Mission
Depending on how your truck came from the factory, you might consider upgrading the alternator. My Power Wagon came with 160amp alt, and I thought it was great until I added a fridge and a second battery to support it. Wound up adding a second house battery to give me 150ah in the house bank plus 105ah in starting battery, plus a 270amp alt. Still not enough in the desert in summer temps. FWIW, the Warn winch on the PW draws 440 amps at max pull, rated at 12,000 pounds but is mostly 15,000 pound components. You will need way more juice than you think.
Wow, that's a heap of power, you must have a big parasitic drain going on somewhere, or it is not wired up correctly, Maybe the charging solenoid is closing off early ?,

Love that Truck, :love: :love:
 

Ducky's Dad

Explorer
The drain is the fridge when outside temps are in the 115-125 range and the cab of the truck is north of 185. I have not installed solar yet but I have a 100W Renogy panel ready to go on the rack as soon as I can get to it. Parasitic drain has been tested multiple times on multiple meters by multiple guys and it's always within spec. I love the truck, too. Best truck I have ever owned.
 
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