Power Option For Fridge In Part Time Rig

[Moebius01]

Ok, it's a little awkward to explain, but... In short, my rig is set up as a part time/convertible. When I'm using for overlanding, I have a custom deck that I put in place of the spare tire cover that has mount points for a drawer cube, and eventually a slider for a fridge (currently eying a setpower rv45d). The WK2 doesn't really have anywhere to hide a dual battery system, and in all honesty I'm trying to do this part on a budget. So I'm looking for a way to power the fridge for up to maybe 36-48 hours without the vehicle running (can use solar to supplement that as well). The easy solution would probably be just getting something like a Bluetti EB70 or the like, plug it in to the 12v in the back of the Jeep (currently set to only have power when engine is running) and plug the fridge into it. That way, when vehicle is running, it would be charging, and keep the fridge

What I'm wondering, is since the cost of a power station like that isn't the cheapest, and has lots of things I wouldn't use (inverter, USB ports, etc...) is there a relatively easy DIY option that would let me achieve the same basic functions for a lower cost? I wouldn't need an inverter, or USB ports, or any of the other bells and whistles. Just a battery with a controller that could charge from 12v or solar, and allows passthrough so the fridge would run while it's charging. I've been searching around, but my knowledge in this area is pretty lacking, so not quite sure where to begin, or even what size battery I'd need to achieve that run time.

 

[leeloo]

you can get a 12 v dc to dc charger like victron
and an 80 amp AGM deep cycle. This will set you back about half price. You will need some wires, a few fuses and if you can install it yourself, your good to go. In time you maybe add a solar panel , or go lithium, this setup is flexible. This 80 AGm should be enough for a couple of days, but it depends how many beers you drink per day.
If you need to go to a shop to do this installation, you are probably better off with the bluetti..
the dc to dc stays hidden installed permently in some spot, when you get back you remove the AGM and keep it on a charger/maintainer.

 

[Ubiety]

I built something like the KickAss portable power station and ran cable from under the hood to the bed of my truck to charge the power station via alternator. Used a 30 amp Renogy DC-DC charger that consumes both alternator and solar for flexibility (solar in base camp situations and alternator for driving trips). I was able to put it all together for about half the price on the KickAss solution and can use whatever battery I want (and replace without tossing the whole thing). I had a deep cycle marine battery that I was able to repurpose until it gives out and I replace it with something else. The whole thing is portable so it can sit inside the house on a trickle charger when I am home, or live at base camp if I go for a drive. I opted for the Renogy BlueTooth unit so I can monitor status from my phone/ipad, whether that be at camp or while driving. Let me know if you want any other details. And... Make sure you get the proper gauge wire to run alternator power to it - nobody wants an unplanned fire ;)

In the truck. Made a wood tray to hold it and bungeed that to the truck. Has not moved in the bumps. Connected the battery to cig plug / USB adapters that I already had and stuck them to the kitchen cabinet with magnets and double sided sticky tape. The Anderson connector connects it to alternator power/sense cables that I ran along the frame.


View of the battery box only. Velcroed appropriate size wrench on to disconnect the battery from cables so it would always be right there. Bluetooth unit velcroed onto side of the box. Ran pigtails out of the box with SAE connectors to attach fridge, canopy lights, cig/USB ports, etc. to.

 

[Ubiety]

BTW - You can get the three pole Anderson connectors from KickAss - handy if you need to run positive, ground and alternator sense wires to the engine compartment.

 

[Luinil Explorations]

Like you I move my camping setup in and out of my Jeep. My solution was to put the lithium system in a milk crate. Makes it easy to put in and take out.

 

[Viking1204]

I built a similar system using a lithium battery that I installed in a Dewalt toolbox, I too have a Redarc DC-DC charger and solar panel. DIY is much cheaper and you want a good place to learn more than you need to know to build a simple systm go to the link below.

Mobile Solar Power: Made Easy! DIY Off-grid Solar Power!

 

[Archipeep]

Wouldn't hurt to just do a dual battery setup with a $20 solenoid so that it disconnects when not running. This way, you'll have the power you need for the fridge, you'll never have to worry about forgetting to recharge it, you wouldn't have to carry a solar panel to charge on the go, and it will just work. All said, its probably $75 plus the cost of the battery (deep cycle). I've used a Duralast deep cycle for YEARS with no issue.


Don't know the make of your vehicle, so engine bay space / battery mount may be an issue.

 

[Ubiety]

So many options! Ahhhhhh! Hahaha

 

[Sparksalot]

BTW - You can get the three pole Anderson connectors from KickAss - handy if you need to run positive, ground and alternator sense wires to the engine compartment.

Very cool. Thanks for the hint.

 

[Ubiety]

Very cool. Thanks for the hint.

The KickAss part has gone out of stock but @reaver found these for half the price.

https://www.digikey.com/en/products/detail/anderson-power-products,-inc./SBS75GBLK-BK/10650419?msclkid=4b0ae1dc0eb911edb7daf7e6a0aaead0&fclid=4b0ae1dc-0eb9-11ed-b7da-f7e6a0aaead0&p=b236f2aa59cf9c9c7f3a3d453d966e88096dfa426a5b1d41eb78146502eb3a0eJmdvaWQ9Mzc3NjIwMTc5OTEmaW10cz0xNjU5MDQyNDUxJnJndWlkPWQ3ZjllYTc1LWMzYTQtNGFjYy04NGZlLWExNDI2NzM2YzBjNCZta3Q9ZW4tdXMmcHZkaWQ9Mjk3MjQ&ptn=2

 

[reaver]

The KickAss part has gone out of stock but @reaver found these for half the price.

https://www.digikey.com/en/products/detail/anderson-power-products,-inc./SBS75GBLK-BK/10650419?msclkid=4b0ae1dc0eb911edb7daf7e6a0aaead0&fclid=4b0ae1dc-0eb9-11ed-b7da-f7e6a0aaead0&p=b236f2aa59cf9c9c7f3a3d453d966e88096dfa426a5b1d41eb78146502eb3a0eJmdvaWQ9Mzc3NjIwMTc5OTEmaW10cz0xNjU5MDQyNDUxJnJndWlkPWQ3ZjllYTc1LWMzYTQtNGFjYy04NGZlLWExNDI2NzM2YzBjNCZta3Q9ZW4tdXMmcHZkaWQ9Mjk3MjQ&ptn=2

They're not half price
That listing is only for the connector. You have to buy the parts that go on the wire separately. So it works out to be roughly the same price.

That being said, it's an option. However, you can replace your starter battery with a dual a purpose rv battery for about 130 bucks from Napa. Supplement this with a 100w solar panel, and mppt solar charge controller, and as long as you have sun, you should be able to stay stationary indefinitely.

You can grab an hqst or similar charge controller for about 80 bucks.

For reference, we have a 100Ah lifepo4 battery in the trailer. We run two cpaps, a fridge, and lights on the trailer. This uses about 25-30Ah/day so far. I have a 20A HQST charge controller paired with a 120W folding solar panel. This combo is able to keep my trailer battery charged easily, and can charge them in about 3 hours in moderate sunlight.

 

[Sparksalot]

They're not half price
That listing is only for the connector. You have to buy the parts that go on the wire separately. So it works out to be roughly the same price.

That being said, it's an option. However, you can replace your starter battery with a dual a purpose rv battery for about 130 bucks from Napa. Supplement this with a 100w solar panel, and mppt solar charge controller, and as long as you have sun, you should be able to stay stationary indefinitely.

You can grab an hqst or similar charge controller for about 80 bucks.

For reference, we have a 100Ah lifepo4 battery in the trailer. We run two cpaps, a fridge, and lights on the trailer. This uses about 25-30Ah/day so far. I have a 20A HQST charge controller paired with a 120W folding solar panel. This combo is able to keep my trailer battery charged easily, and can charge them in about 3 hours in moderate sunlight.

I noticed the contacts are not included. They’re not hard to source though. It certainly gives an option for a removable setup or trailer.

 

[reaver]

I noticed the contacts are not included. They’re not hard to source though. It certainly gives an option for a removable setup or trailer.

They have to contacts as well. I bought some 4 GA, 8ga and 12ga

 

[Moebius01]

I built a similar system using a lithium battery that I installed in a Dewalt toolbox, I too have a Redarc DC-DC charger and solar panel. DIY is much cheaper and you want a good place to learn more than you need to know to build a simple systm go to the link below.

Mobile Solar Power: Made Easy! DIY Off-grid Solar Power!

Some good stuff in there. My current line of thinking/benchmark is working from something like a Bluetti EB55. I figure that would likely get around 36-40 hours of runtime depending on conditions. Cost is around $500 pending any sales or the like. I figure if I can spec a battery box that would have the same rough battery life, a controller to allow either 12v or solar charging, and a 12 v output jack for cheaper (and preferably smaller) then that'd be worth it. Seems right now, by the time I source all the parts, it gets close to or above the cost of a pre-fab.

My main thinking is when I load up for a trip, I plug the fridge into the supply, and the supply into the rear 12v in the Jeep (currently configured to only have power with engine on). So when I'm driving, it's charging, and when I'm stopped, it's running on battery. If I'm stopped for a full day, I can hook up solar to help keep it topped off, or worst case run the engine for a bit as a last resort.

 

[reaver]

Some good stuff in there. My current line of thinking/benchmark is working from something like a Bluetti EB55. I figure that would likely get around 36-40 hours of runtime depending on conditions. Cost is around $500 pending any sales or the like. I figure if I can spec a battery box that would have the same rough battery life, a controller to allow either 12v or solar charging, and a 12 v output jack for cheaper (and preferably smaller) then that'd be worth it. Seems right now, by the time I source all the parts, it gets close to or above the cost of a pre-fab.

My main thinking is when I load up for a trip, I plug the fridge into the supply, and the supply into the rear 12v in the Jeep (currently configured to only have power with engine on). So when I'm driving, it's charging, and when I'm stopped, it's running on battery. If I'm stopped for a full day, I can hook up solar to help keep it topped off, or worst case run the engine for a bit as a last resort.

This will work, but double check to make sure the bluetti has a regulated 12v output (most of the more high end power stations do). If not, tleven with the battery cutoff set to low, the fridge will shut off with about 50% battery left, due to the way the voltage drops in the battery. Otherwise, you'll have to wire in a voltage stabilizer between you battery and 12v port the fridge is plugged into. They're inexpensive, and it's easy to do.

 

[Ubiety]

Some good stuff in there. My current line of thinking/benchmark is working from something like a Bluetti EB55. I figure that would likely get around 36-40 hours of runtime depending on conditions. Cost is around $500 pending any sales or the like. I figure if I can spec a battery box that would have the same rough battery life, a controller to allow either 12v or solar charging, and a 12 v output jack for cheaper (and preferably smaller) then that'd be worth it. Seems right now, by the time I source all the parts, it gets close to or above the cost of a pre-fab.

My main thinking is when I load up for a trip, I plug the fridge into the supply, and the supply into the rear 12v in the Jeep (currently configured to only have power with engine on). So when I'm driving, it's charging, and when I'm stopped, it's running on battery. If I'm stopped for a full day, I can hook up solar to help keep it topped off, or worst case run the engine for a bit as a last resort.

You can replace the battery in a DIY solution but maybe not in a pre-fab? With the proper charge controller a DIY job will be able to charge faster than most pre-fabs.

 

[Luinil Explorations]

You can replace the battery in a DIY solution but maybe not in a pre-fab? With the proper charge controller a DIY job will be able to charge faster than most pre-fabs.

X2 on this. The Kisae ABSO charge controller that we are using is adjustable from 5 to 50 amps and a sensing lead to shutoff when the engine is off. No battery cutoff required. The charger is set to 25 amps so the house battery can be fully charged in about an hour of driving, It also has solar a input. Many of the battery packs have a very slow charge rate when plugged into 12v power.

 

[MazeVX]

So I'm not sure if I missed something. But if you run a good quality fridge, not operating in severely hot climate and supported by solar you can easily run your fridge 48h from your main battery.
I have a 70Ah agm battery and it runs my fridge for 48h without solar and without any problems starting the diesel after. If you can use 100-200W solar you are fine without a second battery.

 

[Ubiety]

So I'm not sure if I missed something. But if you run a good quality fridge, not operating in severely hot climate and supported by solar you can easily run your fridge 48h from your main battery.
I have a 70Ah agm battery and it runs my fridge for 48h without solar and without any problems starting the diesel after. If you can use 100-200W solar you are fine without a second battery.

It's a matter of safety; my starter battery is dedicated to starting and nothing else (while the engine is off). If you are parked in an area with, or close to, others/services it is not a big deal getting a jump start from someone else; if you are miles from someone else then it becomes a completely different matter. There is a lot of variability in the things that you bring up - what if your camp site is shaded and you cannot get your panels in a good sunny spot? What if it does happen to be very warm? What if you are at a base camp for a week? What about loads other than a fridge (lights, pumps, etc)? IMO the cost of a second battery/systems is well worth the redundancy to keep my starter battery fresh. My second battery/system is also portable, meaning it can be removed from my truck and placed in the sun if needed (my solar panels are also portable). Can you get away with one battery? Yes you can. Is that the most flexible/redundant/safe way to go? IMO it is not.

 

[reaver]

It's a matter of safety; my starter battery is dedicated to starting and nothing else (while the engine is off). If you are parked in an area with, or close to, others/services it is not a big deal getting a jump start from someone else; if you are miles from someone else then it becomes a completely different matter. There is a lot of variability in the things that you bring up - what if your camp site is shaded and you cannot get your panels in a good sunny spot? What if it does happen to be very warm? What if you are at a base camp for a week? What about loads other than a fridge (lights, pumps, etc)? IMO the cost of a second battery/systems is well worth the redundancy to keep my starter battery fresh. My second battery/system is also portable, meaning it can be removed from my truck and placed in the sun if needed (my solar panels are also portable). Can you get away with one battery? Yes you can. Is that the most flexible/redundant/safe way to go? IMO it is not.

I carry a jump pack for this reason. While a single a battery is not the ideal solution, I've run a single battery for years with no issues. I've not killed it while camping. That being said, I've actually had to use my jump pack while on the way to an event. My battery died with no warning, and I was able to get it started, and drove to Napa to purchase a new battery.

The point I'm trying to make is that if you're moving everyday, it's definitely possible to get away with a single battery, provided you have a way to jump it in an emergency.