Considering a Dometic Portable Refrigerator -- second battery / charging setup?

[trekster]

Hello, I’m building a 2022 JL 3.6 e torque Extreme Recon. I’m considering a fridge at this time but don’t want to add the second battery. Will the Normal battery setup work with the Dometic CFX3 45 fridge for short 3 to 5 day trips without a secondary battery or charging setup? I believe they are fairly efficient and have systems in them to shut down if the battery gets too low? I appreciate any input! Thank you.

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[bjm00se]

Depends on the food you're carrying. If you're OK with the fridge shutting down at night and the temp rising up a bit you can probably get by.

But if you decide you want more power, built-in two battery systems are complex and expensive for what you get; maybe consider getting a 1000kWh stand-alone hand carried power pack by Dometic, Jackery, or others.

 

[PatriotX]

A PLB-40 is a perfect companion to the 45-sized fridges.

If you plan on no additional battery, an upgraded starter battery may be sufficient.

 

[Reinen]

The 2nd battery is worth it because it eliminates risk and you'll be using the right tool for the job.

1. You'll be using the same battery for the fridge that you depend on to start the engine and recharge the batteries. You can get yourself in trouble this way even with the voltage cut-off as your batteries get older.
2. AGM batteries are not designed for small load deep discharge. AGM is best for a large heavy discharge (like engine start) and immediate recharge. You won't be using the right battery for the job and its lifespan will suffer.
3. Depending on the outside temperature the fridge can deplete the on-board battery overnight. You may have a warm shut off fridge and a largely depleted on-board battery which isn't a great thing to wake up to.

A 2nd battery means the worst case scenario is only a shut-down fridge, the Jeep will always have a full charge. The 2nd battery would also be LiPo/LiFo which can handle small load deep discharge so it's much more suited to the use case.

As others have said, you don't necessarily need a built-in 2nd battery. A portable battery is a good option because you can use it for something else. The only thing with portable batteries is to make sure you can recharge at the maximum rate possible. In practice the challenge is always how much juice you can pump back into it before the next overnight stretch. But at least you never have to worry about starting the Jeep.

 

[zouch]

@trekster

(you don't say as much, but i'm going to ASSuME you're talking about plugging your fridge into the Aux Socket at the back left of the cargo area.)

i'd second the idea of the Dometic PLB-40 for a number of reasons already mentioned, and add that it gives you the option of being able to take your fridge (and the PLB-40) out of the J**p at camp and have it continue to keep things cool camp-side.

not sure about your vehicle, but in our '21 we were able to reposition a fuse in the Power Distribution Center such that the Aux outlet at the back of the J**p is only live when the engine is running. by running this configuration with things plugged in:
fridge > PLB-40 > J**p
means that when you're shut down in camp there's no way your fridge can suck the vehicle starting battery dead, and your fridge keeps running off of the PLB-40.
this will also allow you to set the Low-Battery protection threshold setting of the fridge down to its lowest setting so it won't shut off so easily, because you don't need to worry about draining the Starting Battery.

i will point out that the wiring feeding the Aux outlet at the back is pretty cheesy, and doesn't provide a particularly good power supply.
it was poor enough in our '21 that the voltage was low enough that the fridge would shut off (or just not start up at all) before we put the PLB-40 inline. it is, however, enough voltage that it will charge the PLB-40 while driving and keep the PLB-40 voltage high enough that the fridge stays happy and does its job.
running a better wire would help; i'm in the planning stages of using the Dometic HWK-DC to
a) get the advantage of its 10g wires for quicker/easier(/safer!) recharging of the PLB-40, and
b) put the socket up on the side of the cargo area instead of down where the plug forces me to place the fridge further forward so it clears the plug sticking out of the socket. (as big as these J**ps are, space still seems to be at a premium when we start loading things up!)
i'll probably have to set it up with a relay off of the stock Aux socket so that i can still have it triggered by the Engine running (or not), but it should all be do-able; i just haven't opened the panels up yet to see where the Aux socket wiring disappears into the vehicles wiring harness.

 

[Vinman]

I have an Engel that I purchased in 2003 and have only drained my single battery a couple of times, usually after 3 days or so without the vehicle running. While a dual battery system is nice, if you run the engine for 30 or so minutes a day that should provide enough charge to keep up with the fridge.

I should also add, my fridge has no low voltage protection built it and will just continue running until the battery is completely drained. The last time I drained it down to around 5 volts after forgetting the fridge was plugged in and letting the Jeep sit for about a week.

 

[JINO]

I have a delta 2 (ecoflow) with a dometic fridge, and it'll last around 3 days. Can be charged with 12v and solar, I have 220 watt panel and with full sun, I can fully charge in about 4 to 5 hours.

 

[COJeeper]

I've got a Dometic CFX3 45 and I left it in the Jeep overnight connected to the 12V in the trunk (or whatever you call it). I left it for 24 hours with nothing in the fridge (makes it work harder) at -7 degrees. I think the battery still was around 11.8V. I'll be taking it on a trip to The Maze District in Canyonlands this June, it'll have to work harder as it'll probably be hot in the desert, I'd assume, but I'll be moving daily so only one night on the Jeep battery.

Eventually, I plan to get some solar system. That will probably be 2024 though, we're broke now.

 

[trekster]

I probably will be using the refrigerator on one day trips for the most part and longer once a year. I’m not set up to overland. Great information, because of the limited use would like to go as economical as possible.

 

[JeepSmash]

Most fridges should have battery protection. Will you be starting it up each day? I run my fridge 24 hours a day while camping but I also drive trails each day. No issues with it ever turning off due to voltage.

I run the Alpicool CF45 with LG compressor. Affordable and been totally reliable.

 

[trekster]

Most fridges should have battery protection. Will you be starting it up each day? I run my fridge 24 hours a day while camping but I also drive trails each day. No issues with it ever turning off due to voltage.

I run the Alpicool CF45 with LG compressor. Affordable and been totally reliable.

Yes, I’ll be running the Jeep for 5 to 8 hours a day on the 5 day trip, day trips all day. Do you think running the fridge shortens the life of you batteries?

 

[JeepSmash]

Yes, I’ll be running the Jeep for 5 to 8 hours a day on the 5 day trip, day trips all day. Do you think running the fridge shortens the life of you batteries?

I don’t think it does in any large way. Especially since you’re only doing it once in a while anyways. If it concerned you enough you could run the fridge on a small portable battery when you park. The fridge should tell you your Battery voltage though so you can keep an eye on where it’s at. I did 5 days going around Death Valley with it plugged in the whole time. No issues.

 

[Ratbert]

Make sure that you order the tow package. That'll give you a larger alternator as well as make it easier to wire up accessories.

 

[El Zilcho]

I have dometic 35 and I had it in my jeep in Moab in summer (really hot) for 5 days without turning it off and without any problems with a battery. And it never turned off at night. As long as you drive it every day you will be fine.

 

[trekster]

Most fridges should have battery protection. Will you be starting it up each day? I run my fridge 24 hours a day while camping but I also drive trails each day. No issues with it ever turning off due to voltage.

I run the Alpicool CF45 with LG compressor. Affordable and been totally reliable.

Make sure that you order the tow package. That'll give you a larger alternator as well as make it easier to wire up accessories.

That’s a good point, luckily I do have the tow package. Thanks

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