Battery for fridge

[rubicondon53]

I'm planning to install a 12 volt redtop on my trailer for powering a refrigerator. I'm thinking about the best way to keep it charged. Obviously a trickle charge of some kind. Are there any good write ups anywhere on how to properly wire this up? Thanks for all advise..

[youwillforget]

I can give you some information to think about and then you decide what works for you.

If you leave home with a charged battery the 7way is kind of just keeping the battery topped off and powering the fridge while traveling to camp. It will transfer around 7-10amps to the battery while the engine is running so hook it up it is worth the effort.

Almost any single deep cycle battery will yield roughly 90amp hours and you have to put back in what you use. If your fridge uses 2 amps an hour you can run it for roughly 45 hours then you have to charge the battery. Chargers are pretty easy to figure out they come in all sorts of ratings 2, 8, 15amp so figure charger amps x hours hooked up to power = rough charge times.

There is way more to it than that and this thread will turn to 90 posts of arguments before you know it.

If you would like more information I would be more than happy to tell you what I know and try to guide you best I can.

[Aspen Trails Trailers]

The 12 volt input from the truck's charging system is the most important I think, just besure to isolate it, so it does not run the truck battery down. A small solar panel will normally keep it at tip top shape as long as you have sun. A Morningstar digital solar controller will keep it working and not allow the battery to be ran down to a dangerous level. A small Honda 2K generator will charge the battery, run the fridge on a 110 circuit if installed.

Many ways to do it, but the most economical is as stated above. The rest is overkill, unless you plan to be out in the woods for a couple of weeks.

[rubicondon53]

We do go out for 4 or 5 days at a time, and the wonderful old 7 day ice chest works well with block ice, but, a fridge would be much better, so if I have a fridge that draws 5 amps, and I trickle charge it with 7, then it should keep up while traveling, and have plenty of juice for overnight at camp,, I'm intrigued by solar power, seems the simplest way to go, but I'm a bit leery of solar reliability, so I may end up tapping my jeep for the charge.. Nonetheless, I don't want to end up with spoiled food because of unreliable methods.. So I'll stick with hardwiring from the jeep.. Do I simply run a fused hot wire to the trickle mechanism? And how best to ground everything? Thanks.. .

[youwillforget]

7 way hot and ground run across battery then the gorund goes to the frame. Did the TV come factory tow package 7 way plug?

I am reserching solar now. 90amp hour battery bank discharged overnight would have to be recharged in approximately 5 to 6 hours so I need to put 15amps an hour back in so 15 x 12 = 180watts and that isnt figuring in 80% duty cycle. Funny thing is that you would have to run a generator with a 15amp battery charger for 5 to 6 hours too or turn the TV around and use jumpercables to connect the TV and trailer battery together because you get about 20 amps hooking it together like that.

[Aspen Trails Trailers]

A good solar battery will not run down overnight with a ARB type fridge, ran mine for four days at Expo. I have dual batteries though. But never got close. The fridge does not draw constinously, only when it is running, which is not that often. Mine draws .5amp normally I think, could be more, never really paid any attention to it. I run a Dometic.

Buy a quality charge controller and you will never have problems. It will tell you how much you are using, how much is left in the battery and the state of the battery. I use a Morningstar digital 15amp in all of my trailers. I have used them solar towers, that I build for the last 12 years. Very good if not the best piece of equipment I have bought for solar.

[cold_n_wet]

But maybe a yellowtop is better due to the discharge and charge, I thought red tops were start batteries? If thats what you have to hand then ok.

How about running a line from you trucks batteri via a VSR (voltage sensing relay) to an Anderson style connector at the back. You should also consider to put in an isolating solenoid should the need arise to cut the power to the trailer quickly.

The VSR will allow power to the battery when the truck is started and has over 13,2V on the contacts.

The only down side if you start and stop often, the battery which is discharged will steel power from the charged battery, just be aware of that if you have been stationary for a few days then start the truck to move it a few minutes.

I am about to run lines to the back for my project, but I have a split charge system on the truck, so I just need to connect to the trailer. I have a yellow top on the truck and a 90 AH AGM china battery on the trailer.

I am running heavy lines so that I could power a winch off the back end in the future should the needs arise.

Good luck with the installation.

Glen

[fifty]

This is a great thread. I am just starting my research for a fridge system where the battery is completely recharged by solar.
All of this mounted on the trailer.

[youwillforget]

In short you have to know how much power you will uses for your type of adventure. The guy that sets up camp in 1 spot for 3 or more days is going to need more energy storage or solar generation than the guy that sets up camp 1 night then tows his rig down the trails/unimproved roads for hours a day.

Personal Experience
I have 75’ of 2/0 in my garage that I will be using part of on my jeep so I can run my Winch front or rear. I will be using Anderson SB175’s to make the connection. I will be making up a 2 Gauge cable to connect the 4 Group 31’s in 2 banks on the trailer to the Jeep so I can take full advantage of the Alternator in transit. I also have a 2amp, 15amp battery charger and a 2400watt generator and I am looking into quality solar.
My trailer is set up more for service and recovery than trails. I love trails but in North West Indiana don’t offer a lot of them.
In the last 2 months I used my batteries, generator and 1025watt inverter to provide power to my Aunts house in South East Illinois for 2 nights while I replaced her circuit box in her house and the Meter box on the outside of her house. I put the 2 circuits the TV’s were on through the inverter and the rest of the house on the generator. We got lucky with the weather so the A/C wasn’t needed and we just watched what we turned on the rest of the time. The power company only offered one time a day for the on off service so we spent 2 days without grid power.
I anchored my 10k Winch to a tree with a tree strap and pulled my Uncles dump truck out of a sink hole on his property, my jeep would have never pulled that truck out but my support equipment was still used. I made the recovery then took the rig home and recharged the batteries on grid power.
This is what works for me and I would never expect someone to do something the way I did because that may not work for them. There is a guy on one of the RV forums I read that is really good with solar and is gracious enough to put that information out for others to benefit from but he states multiple times that if you don’t do things the way he does you are an idiot. I don’t live in an RV full time so his setup isn’t right for me but if I use solar and don’t do it his way he still considers me an idiot.

[Black_ZJ]

Another option is running dual 6-volt batteries, you could get almost double the reserve capacity over the Optima and not need to recharge for 4 or 5 days.