Fridge power?

[off-roader]

One thing I've seen done and also plan to do is to mount a small 12v deep cycle AGM battery in the back. That way I don't run down the starting battery (even though that's also a deep cycle) overnight should something go wrong with my ARB fridge. I saw this setup in Grasscat's rig and it was pretty sweet. When wheeling he simply plugged the small battery back into his rear cigarette lighter outlet to recharge it.

[BIGdaddy]

One thing I've seen done and also plan to do is to mount a small 12v deep cycle AGM battery in the back. That way I don't run down the starting battery (even though that's also a deep cycle) overnight should something go wrong with my ARB fridge. I saw this setup in Grasscat's rig and it was pretty sweet. When wheeling he simply plugged the small battery back into his rear cigarette lighter outlet to recharge it.

i like this idea. Would one need to vent this battery or seperate it in any way from the passenger compartment?

[JPK]

No, not if it's an Absorbed Glass Matt, or AGM. No fluids. And no venting except upon over charging. If you use a cigarette lighter to charge the battery the truck's voltage regulator will limit voltage and you won't over charge the battery.

Personally, I like the low voltage cut off switch better, takes up no room. If I did a lot of really remote exploring, I'd use a second battery though.
[Edit to mention that you would always want to prtect the battery terminal so that no "accidental discharge" ocurs. Like when something metalic lies across both terminals. That would drain the battery, but also be a fire hazard, so a battey box or something to gaurd the terminals (and secure the batttery) would be all that is required.]

JPK

[off-roader]

No, not if it's an Absorbed Glass Matt, or AGM. No fluids. And no venting except upon over charging. If you use a cigarette lighter to charge the battery the truck's voltage regulator will limit voltage and you won't over charge the battery.

Personally, I like the low voltage cut off switch better, takes up no room. If I did a lot of really remote exploring, I'd use a second battery though.
[Edit to mention that you would always want to prtect the battery terminal so that no "accidental discharge" ocurs. Like when something metalic lies across both terminals. That would drain the battery, but also be a fire hazard, so a battey box or something to gaurd the terminals (and secure the batttery) would be all that is required.]

JPK

The AGM battery I'm looking at is an Interstate unit that is very small and has screw on terminals so you can likely easily insulate them to prevent accidental discharges. Securing it is the thing I need to focus on now. I also thought about getting a low voltage cutoff switch. How much are they? Any recommendations on a reliable one?

[2drsrbtrrthn4]

I'm pretty sure my ARB fridge fried my 12v AGM main battery by running it out of juice a few times. I even utilized the low-voltage cutoff built into the fridge. To eliminate this from future occurrences, I have installed a dual battery controller and smart isolator. The setup goes like this- run everything off your main battery, (now a deep cycle AGM) and you will always have the 2nd battery (yellow top) for emergency starting of the vehicle. The controller monitors voltage in both batteries so its easy to visually see what kind of state they are in, as well as providing an audible alert should voltage go too low. It gives me the control to join the batteries in case I run the main down below the voltage needed to start the vehicle.

All that said, I'm running a rear compartment Blue Sea fusebox directly off the main battery with 8ga wire. The fridge plugs in with the Hella plug and socket.

Fingers crossed...

[JPK]

The AGM battery I'm looking at is an Interstate unit that is very small and has screw on terminals so you can likely easily insulate them to prevent accidental discharges. Securing it is the thing I need to focus on now. I also thought about getting a low voltage cutoff switch. How much are they? Any recommendations on a reliable one?

To run a fridge you would want a deep cycle battery, typically in the sizes we're discussing, a marine or maybe RV battery.

I have been successfully using a cheap KollTron 12v extension cord/cut off switch between my Engel and a cigarette plug for about 15 mos. My one and only battery is a Grp 31 Blue Top Optima (Yellow Tops are also deep cycle, but in my area, near Annapolis, MD on the Chesapeake Bay, it's easier to find the (slightly more expensive) Blue Tops. Sears Die Hard Platinum marine batteries are TOP quality, reportedly made by Odyssey, which sells deep cycle and starting batterries under their own brand too. Also, while adapters from typical automotove lead post terminal to screw terminals are easy to find, the marine batteries almost all have two sets of terminals, the typical automotive posts and also screw terminals.

Here's a link to the cheap ($27) and effective KoolTron extension cord/cut off switch - which cuts of fridge power at 11v, ok for a deep cycle but too low for a starting battery, imo. http://www.roadtrucker.com/koolatron...ccessories.htm

JPK

[Black_ZJ]

One thing I've seen done and also plan to do is to mount a small 12v deep cycle AGM battery in the back. That way I don't run down the starting battery (even though that's also a deep cycle) overnight should something go wrong with my ARB fridge. I saw this setup in Grasscat's rig and it was pretty sweet. When wheeling he simply plugged the small battery back into his rear cigarette lighter outlet to recharge it.

I know the thread is a few months old, but do you know what gauge wiring he used from the front to the rear outlet, and from the outlet to the battery?

[trevan]

I have recently purchased an ARB fridge and having been looking through the forum for info on how to wire them in.

One of the earlier posts talks about a small battery used to power the fridge when the engine is off and the use of the aux outlet when the vehicle is operating.

I have an interim setup that is similar.

My question is could you connect the battery to the aux outlet and then the fridge to the battery. If the Aux outlet turns off with the ignition key then the fridge maintains power from the battery and in turn when the engine is running the battery would receive a charge.

Seems so simple that it must break some wiring principles!

Jim

[Jay H]

I have recently purchased an ARB fridge and having been looking through the forum for info on how to wire them in.

One of the earlier posts talks about a small battery used to power the fridge when the engine is off and the use of the aux outlet when the vehicle is operating.

I have an interim setup that is similar.

My question is could you connect the battery to the aux outlet and then the fridge to the battery. If the Aux outlet turns off with the ignition key then the fridge maintains power from the battery and in turn when the engine is running the battery would receive a charge.

Seems so simple that it must break some wiring principles!

Jim

It might work but there are quite a few potential problems with this.

1. You need fuses ideally one between the aux and second battery and also one between the fridge and second battery. Think vehicle fire.........

2. In my 2004 toyota the aux is regulated to 12.6 volts meaning a battery connected would never fully charge - this problem is huge and would kill a battery in short order.

3. Does your vehicle disconnect the aux socket while starting because if not current could flow from the second battery to the main battery while starting and it could be enough current to blow the fuse. And dont let any one tell you a simple diode will fix this. It will, but it it will also drop voltage and use a good bit more power. The voltage drop of a cheap diode will probably even be enough to cause low voltage cut out problems. In my toyota the 12 sockets and the stereo are disconnected while starting which is good for not killing sensitive electronics by feeding them low voltages.

4. Your fridge will run a little AGM battery flat pretty quick when sitting in the sun so a low voltage disconnect to protect the battery is a good idea. Most of these cut out circuits do not kick in soon enough. An average AGM battery will cycle half as many times before dying if run to below 50% capacity.

5. When the engine is running the vehicle would have to power the fridge and provide a charge, this could be quite a few amps depending on the size of the second battery.

[trevan]

Thanks for the great response! I thought it was too good to be true.

Two quick q's.

1) If I run a dedicated line to the fridge from the main battery do you think 10 gauge is good for a max run of 15'?

2) Is there a practical way of wiring up the remote battery in the rear of the truck so it can obtain a charge through the main battery or the Alternator? I have read a lot on this and there does not appear to be a clear answer. The typical solution appears to be two batteries under the hood but I have no room. Instead I have a large AGM battery for the truck and the winch. May not be a huge issue if I connect to the main battery as I can easily last 4 days on it and still get started. I have a low voltage cutout. In most cases I would only be traveling on the main and then switch over to my remote AGM battery which has a 100ah rating.

I see you are into cycling! After too many years in the sales rat race I took on a role in a not for profit cycling organization on the sport side. Early on I worked on bring IMBA into Canada. We are heading off in a week to act as Trail Host's at a Mountain Bike trail system in one of our provincial parks.

Jim