Dead Jeep Battery / Dometic Fridge

[Wolf Island Diver]

There are some lithium starting batteries on the market with built in charge controllers to mesh with your electrical system. They’re designed to be starting batteries. I don’t think electrical system compatibility is an issue as others frequently state on this forum as long as they can deliver the amps when starting and winching if that’s relevant. However, I don’t think they’re worth it. For a starting battery, unless you’re looking to shave small amounts of weight off, for say a racing application, they’re just a solution I search of a problem. A functioning alternator will keep an AGM topped off until it starts to fail. I’d also double check the manufacturer’s stated operating environment. The under hood of my JTRD gets hotter than any other vehicle I’ve ever owned. I’ve had a lot of stuff warp/melt. Supposedly AGM doesn’t even do well in this heat. I wouldn’t be surprised if batteries are failing more frequently on our trucks.

For the fridge, I’ll parrot what others have said: a completely separate lifepo-based “house battery setup”. I run a 100AH Renogy-based system that I built with a base of 100w of solar. It will run my 63QT ARB fridge and lights indefinitely off grid. It was less than the cost of a 1000WH portable solar generator. Personally, I’d skip right over any of those systems unless you want something quick and easy and you think you’ll still have a use for the generator after building a bespoke system. I still use my GZ Yeti for charging phones, Nintendo, etc.
You can sometimes get 500WH generators pretty cheap <$500. That’s sufficient to run the fridge when you’re truck isn’t running.


Here’s the thread on my house lifepo system built in-bed. You could build something less involved mounted under the rear seats as others have done, but 100AH is a good starting point.
https://www.jeepgladiatorforum.com/forum/threads/renogy-lifepo-house-dual-battery-install.71866/

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[clarkhogan]

I just did EcoFlow alternator charger and a Delta two max. Benefits are that it charges the system at 800 W in <90 mins, it’s an LFP 2048 Wh, alternator charger system is lighter and can reverse charge the Jeep battery from the Delta lithium battery or from solar and I can run the dometic easily for 2+ days without starting the motor. I found the dometic was really fussy about long wire lengths from the battery to the bed with line resistance, causing freezer to shutdown on long roadtrips as the jeep charging system alternator cutback tends to drop to 11.8v when system gets hot. Dual battery set ups are unnecessary anymore. it’s lighter and less expensive when buying refurbished, with lithium batteries 10,000 charge cycles make used systems worry free.

 

[ColoradoCantu]

As other have mentioned, I would not use an expensive Lithium battery for your starter battery, I went with next size up battery, an Optima group size 94R when my aux battery died. Both we were original so I decided to replace both at the same time since it was just matter of time for my starter battery to fail.

 

[Wolf Island Diver]

@clarkhogan reminds me of something important about these dc-dc chargers. Mine also includes the MPPT solar charger. While the alternator will charge both batteries, the dc-dc charger will also reverse charge the starting battery when on solar if the house battery is full. Mine does this all the time which is a nice secondary benefit.

 

[ttn333]

@clarkhogan reminds me of something important about these dc-dc chargers. Mine also includes the MPPT solar charger. While the alternator will charge both batteries, the dc-dc charger will also reverse charge the starting battery when on solar if the house battery is full. Mine does this all the time which is a nice secondary benefit.

Forgot about that tidbit only because my truck never sits there that long to make that feature useful.
You can build a relatively cost effective unit with a 100ah lifepo4 (from Renogy or Litime). Drop it in premade battery box and slap a charge controller on it. Then wire it to solar and/or your vehicle.

 

[Blade1668]

I believe they are both original. I was hoping this would be the problem. Thank you.

Anyone have any suggestions for the best lithium replacement starter battery for a 21 diesel JT

I plan on a redarc dual system next year and will be using their auxiliary lithium for that

A point that has been beaten up already, a stand alone house battery system might be your best choice for the fridge freezer. I noticed that your in OH. not prime weather in winter for LiPo batteries, our resident who is using Lithium starter battery is located in LA CA. area not quite as cold in winter. I'm in N. AL. and have had lithium battery shutdown due to cold, it was a inconvenience for lights the fridge freezer was a non-issue then. My original lithium batteries are now in a battery box as a portable setup. Similar to above.

Two 36AH LiPo batteries, usable for my trolling motors in pond prowler boat and what ever else. Including a 2k electric winch 3 weeks back.

 

[keithcroshaw]

I would never risk my starter battery to run my fridge.
I just have a little ecoflow battery to keep it running when the ignition isn't on. Then I plug that in whenever I'm near shore power.
I built a little power switch so I can switch from the bed power supply (which sucks) to shore power with the turn of a switch. (There's a center no connection position before anybody gets upset.)

 

[JTGuy]

I run my Dometic fridge off my Bluetti battery pack. The jeep keeps it charged. No issues. Simple. The batteries in my JT are 2 years old now and I expect to be replacing them in the next year. I carry a battery jumper all the time as there will be no warning to the non start.

 

[MarkusAurelius]

UPDATE:
Both starter and aux battery were dead and needed replaced. In the future I intend on deleting the auto start/stop eco feature. For now im in need of a solution for a battery in the back. I want to go with the redarc system but dont want to go ham just yet. Looking to get the bare minimum to charge their battery from my alternator and rooftop solar panel. Next year Ill get fancy with it but for now I wanna get up and running the cheapest way I can with using redarc systems. Going to make a new thread to get specific. Thanks for all the help. This forum is remarkable.

 

[smlobx]

UPDATE:
Both starter and aux battery were dead and needed replaced. In the future I intend on deleting the auto start/stop eco feature. For now im in need of a solution for a battery in the back. I want to go with the redarc system but dont want to go ham just yet. Looking to get the bare minimum to charge their battery from my alternator and rooftop solar panel. Next year Ill get fancy with it but for now I wanna get up and running the cheapest way I can with using redarc systems. Going to make a new thread to get specific. Thanks for all the help. This forum is remarkable.

I went with the Redarc BCDC1240 and have been very happy with it.

Heres a write up I did on another forum starting on post #71…

https://americanadventurist.com/forum/threads/meet-sherpah-my-gladiator-build.7090/page-4

I have taken this set up on multi week trips from sea level to 12,000 feet and from 24 to 95 degrees and it has worked flawlessly.

 

[MarkusAurelius]

I went with the Redarc BCDC1240 and have been very happy with it.

Heres a write up I did on another forum starting on post #71…

https://americanadventurist.com/forum/threads/meet-sherpah-my-gladiator-build.7090/page-4

I have taken this set up on multi week trips from sea level to 12,000 feet and from 24 to 95 degrees and it has worked flawlessly.

Thanks bro. I checked out the build awesome. Your post #71 just rose awareness to the possibility that i may need stronger axles. Im carrying 30 gallons of fuel/water/drinking water, rtt, decked drawer, rsi smartcap and a ton of gear on top of that with anker battery and a cfx 75 fridge. Definitely going to get it weighed and research rear axle options. With my clayton offroad Diesel premium lift with HD springs, it rides like a cadilac but has a little dip in the back. May need to see if airbags are compatible with those springs.

What are you powering with your battery setup?

 

[smlobx]

I have

Thanks bro. I checked out the build awesome. Your post #71 just rose awareness to the possibility that i may need stronger axles. Im carrying 30 gallons of fuel/water/drinking water, rtt, decked drawer, rsi smartcap and a ton of gear on top of that with anker battery and a cfx 75 fridge. Definitely going to get it weighed and research rear axle options. With my clayton offroad Diesel premium lift with HD springs, it rides like a cadilac but has a little dip in the back. May need to see if airbags are compatible with those springs.

What are you powering with your battery setup?

paid a lot of attention to my weight and done everything I could to minimize it including deleting the rear seat and going with lighter tires than the Falkens. I too have a 30 gallon water tank for times that I may find myself in a deserted beach for a week or so but usually only carry about 10 gallons at a time. I do have the LRA fuel tank so when full that adds considerable weight but when you need fuel you need !

I'm charging the system in one of 2 ways. The BCDC system is charged through my vehicle's battery when I'm driving. It literally only takes about an hour to fully charge. When I'm stationary for a few days I have an Overland Solar foldable panel that is very compact and works great. We've never had an issue running out of juice.

 

[teedee29]

I just did EcoFlow alternator charger and a Delta two max. Benefits are that it charges the system at 800 W in <90 mins, it’s an LFP 2048 Wh, alternator charger system is lighter and can reverse charge the Jeep battery from the Delta lithium battery or from solar and I can run the dometic easily for 2+ days without starting the motor. I found the dometic was really fussy about long wire lengths from the battery to the bed with line resistance, causing freezer to shutdown on long roadtrips as the jeep charging system alternator cutback tends to drop to 11.8v when system gets hot. Dual battery set ups are unnecessary anymore. it’s lighter and less expensive when buying refurbished, with lithium batteries 10,000 charge cycles make used systems worry free.

Side question here... I'm installing the ecoflow alternator charger as well. I'm running it from battery through firewall to the bottom of driver seat. However, the cable and quite thick and I'm having a hard time stuffing it through the bottom door sills area. How did you run your

 

[clarkhogan]

I ran all the way to the bed in the trunk which is where Bat and fridge are. I have a bed cap.

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