Battery box / pack question

[SameGuy]

I have an ARB 63 fridge that I would like to run off an AUX battery in my Tundra. I was thinking about doing a dual battery setup for the truck but I haven't found a good place to put the extra battery and I'm not all that keen on fabing something and cutting holes in my new truck to run wires. I thought I could buy one of these:
http://www.amazon.com/MinnKota-Trolling-Motor-Power-Center/dp/B015ZLI4O2
Put an AGM deep cycle battery inside and put it behind the back seat in the Tundra. I could then charge it off the cigarette lighter while running the truck and power the fridge when parked. I realize I will only get a few days run time but I usually drive a bit once camped so that should top off the AUX battery or at least keep it charged enough to run the fridge. I'm wondering if there is a charge controller or anything else I would need to go from the vehicle cig lighter to the AUX battery or if a straight connection would be ok. Also wondering, since the cig lighter is only 10 amp could I overheat the wiring if the AUX battery is too low.

 

[Ducky's Dad]

I have an '08 Tundra CrewMax and have not found a good place (yet) to put a big aux battery. The battery box in the Tundra is big enough to drop in a Grp 31, so that might be a sensible upgrade. And then carry a lithium ion jump pack as backup. I have a Northstar Grp 31 AGM in mine. It looks like there is space behind the grill for a small 12V battery on a fabbed bracket, and it would be simple to wire in a manual isolator switch, as long as you are willing to open the hood to work the switch.

 

[fredgoodsell]

I have an ARB 63 fridge that I would like to run off an AUX battery in my Tundra. I was thinking about doing a dual battery setup for the truck but I haven't found a good place to put the extra battery and I'm not all that keen on fabing something and cutting holes in my new truck to run wires. I thought I could buy one of these:
http://www.amazon.com/MinnKota-Trolling-Motor-Power-Center/dp/B015ZLI4O2
Put an AGM deep cycle battery inside and put it behind the back seat in the Tundra. I could then charge it off the cigarette lighter while running the truck and power the fridge when parked. I realize I will only get a few days run time but I usually drive a bit once camped so that should top off the AUX battery or at least keep it charged enough to run the fridge. I'm wondering if there is a charge controller or anything else I would need to go from the vehicle cig lighter to the AUX battery or if a straight connection would be ok. Also wondering, since the cig lighter is only 10 amp could I overheat the wiring if the AUX battery is too low.

I have that minn kota box. You would definitely need some kind of DC to DC charger in order to charge the battery in the box from your vehicle while traveling. The battery box has no charging capability built in.

 

[Happykamper]

Do yourself a favor and get an arkpac 730. They work great . Best investment ever . I have duals, but I got one of these and am very happy all the way around. Plus it goes from vehicle to vehicle

 

[SameGuy]

I checked the back cig lighter and it is putting out 12-14 volts, depending on engine RPM. I would think it would charge the deep cycle battery without too much trouble. IT may charge slow but I really don't need to top it off every day. I don't understand why I would need a DC to DC charger, I wouldn't have one if I ran cables directly off my battery, through an isolator to it.

I may just set it up as a second battery with a blue sea isolator and call it a day. The arkpac looks cool but WAY overkill for what I need. Funny you should mention a honda generator. I have one of the little ones that I bought years ago just to top off my camper batteries. I think I used it once for that. I wound up adding a second 100AH deep cycle to my camper and have never needed more juice, even after a week of running the fridge, Propex heater and a few meager lights.

 

[4x4junkie]

I checked the back cig lighter and it is putting out 12-14 volts, depending on engine RPM. I would think it would charge the deep cycle battery without too much trouble. IT may charge slow but I really don't need to top it off every day. I don't understand why I would need a DC to DC charger, I wouldn't have one if I ran cables directly off my battery, through an isolator to it.

It is because of the voltage drop within the thin wiring going through a cigar lighter connection (that 14.whatever volts you measured will very quickly become that of what your aux battery is when you make the connection = only a tiny amount of current will flow). A DC-DC converter helps to step the voltage (and current) back up a bit but will still be limited by the 10-amp capacity of the circuit.

With a proper hard-mounted aux setup, the wiring would typically be #4 AWG at the smallest (#0 or #2 ideally). You can pass far more charging power through such wiring than you can through a thin little cigar-lighter cord. Yet even at that it can still take hours of running the engine to bring a significantly-discharged aux battery back to near 100% (so it's probably best to hang up the thought of trying to do it thru the cig-lighter).

 

[SameGuy]

Thank you 4x4. After reading your post and I did a little research. My plan would probably get me by but not without running my AUX battery lower and lower and never getting it charged all the way up, shortening the life etc. I'll just do it right the first time.