Auxiliary Battery Placement

[Rob in MT]

I am planning on installing an auxiliary battery with isolator. For optimum charging, where is the best location for the auxiliary battery, in the camper, or in the engine compartment? Or does it matter? If I add solar does the battery need to be as close as possible to the panel or can in sit in the engine compartment? Thanks for your help.

 

[pods8]

Voltage drop can factor in to battery placement depending on the current you are trying to pass and wire gauge (larger the gauge the less the voltage drop will factor in). So that can make a difference if you're starting with a voltage you want to hold. I put more weight in the proper voltage than anything. If you are going to arbitrarily throw any voltage at the battery then I personally don't think actual placement is going to matter much in the optimum charging decision.

For solar again after the solar controller (which selects a voltage) you're going to want to minimize drop, pick your wire size based on the current/distance and the physical location shouldn't matter as much.



The discussion of in the engine compartment verse in the camper to me would be more based around what battery type you are going with (agm/gel can be in the camper without venting them, flooded cells need to vent and also be maintained by topping off the fluid levels which would probably be nicer in the engine compartment). Also temperature can be a consideration. The colder a battery is the smaller its capacity is, if I was doing a bunch of cold winter camping I'd want the batteries inside the camper so while boondocking they are hopefully warmer than if they were in the engine compartment and thus you'll have more available power.

 

[dsrtrat]

I moved my Interstate agm 75 amp hour battery from the camper to the engine compartment and mounted the isolater on the firewall. The solar controller is in the camper and everything works fine. As Pods 8 mentioned you will need to use a larger wire between the battery and camper. I used 2/0 welding cable (overkill but I had it around). You can find wire size information in the isolater instructions.

Make sure you fuse everything. I used #10 wire from the truck battery to the isolater fused at 30 amps. If you use the optional starting feature you will need much larger wire and fuses. From the aux battery to the camper I used a large fuse holder from a car audio store and also fused the 2/0 wire at 30 amps. I used Anderson 175 amp connectors to make the tie between the truck and the camper.

I ran a 12 volt female Marinco trolling motor receptacle through the camper wall and use the male plug to tie into additional outlets in the truck for my cab mounted Engel fridge. This way the fridge runs off the camper battery. I made an adapter to tie the plugs together if the camper is off the truck.

I also made provisions for an additional battery in the camper if I find I need additional power. So far I have been fine with the single battery and I like the extra space I gained by moving the battery. May be overkill as you can save a bunch of money and work by just keeping the battery in the camper.

Dsrtrat

 

[UglyScout]

I went with my battery in the camper under the front bench in the middle. It makes it nice to be able to have power to the camper when it is off the truck. Test, working on it, cleaning, etc is much nicer when you have full power.

I already have 2 batteries undere the hood, so I was out of room for that option as well.

 

[Barko1]

I went with my battery in the camper under the front bench in the middle. It makes it nice to be able to have power to the camper when it is off the truck. Test, working on it, cleaning, etc is much nicer when you have full power.

I already have 2 batteries undere the hood, so I was out of room for that option as well.



No room under my hood either, already 2 batteries there so I also put mine under the front bench. Inverter sits next to it, solar controller is nearby, easy 12v connection to my coleman/stirling cooler, good weight distribution.

 

[camelracer]

I didn't have room under the hood and wanted the room in the camper so I mounted 2 batteries under the truck bed between the frame and sidewall.

 

[generubin]

I didn't have room under the hood and wanted the room in the camper so I mounted 2 batteries under the truck bed between the frame and sidewall.


Camelracer, I have nearly the same truck and would like to do the same. Can you please post pictures? Size of batteries? Are they attached to the chassis or the underside of the bed?

Gene

 

[Desert Rancher]

Mine sits in the truck bed, just in front of the wheel well on the right side.

I mounted a battery tray to the bed to hold it in place, prior to installing the camper. It's a tight fit, but that space is otherwise unused. This also allows ventilation to the outside.

It is charged through the trailer hitch circuit, plus a 40w solar panel.

As Barko mentioned, weight distribution should also be considered for battery placement.

 

[generubin]

Desert Rancher,

Your location is exactly what I had planned to do with mine. I am picking up my ATC Ocelot on Friday. I had wanted to get the battery mounted first and planned on the same location as yours but the guys at ATC said it would be in the way of the turnbuckle. If I could be more patient, I would just wait until I return home with the ATC and decide then. My current battery is even smaller than yours, it is a 55 amp AGM.

I prefer to mount the battery to the truck rather than in the camper to save space and because when the camper is off the truck, my secondary battery can still be used to power my communications radio, flashlight charger and walkie talkie charging base.

For my ATC, it is a shell model, I need only power lights. I may make those all LED which will allow me to use an even smaller battery such as one of those nice, slim 18 Ah units. I suppose, once I have the camper here, I'll figure it all out.

Gene