How new is your jeep? An issue I (and many others) have run into charging a deep cycle battery only from a newer model tow vehicle is that modern vehicles use a multi-stage charging scheme. This lengthens battery life and apparently improves mileage by reducing the draw on the alternator (this last part I'm skeptical of). The fact is, between the voltage drop from the wire run and that your vehicle may be reducing the charge voltage because it is only accounting for the vehicle battery you may not get a high enough voltage to charge your deep cycle battery in the trailer fully. For me I rely on battery operated everything so having a fully charged battery when I arrive at my destination was important.Thanks for all the help guys. I think im going to make it easier on myself and do this system in phases. I plan on doing more off the grid camping than campsites, so I want to be able to charge my battery while driving and not require any shore power. This would mean that I would more than likely have to connect my inverter to the jeep. I can incorporate a shore charger in the near future. This would simplify my set up and installation.
Can anyone recommend a good "bang for the buck" deep cell?
I plan on using 10ga from my jeep battery to the trailer for the battery charger. What gauge would you use to run from the battery to my fuse panel?
There are solutions to this issue but they aren't cheap. For example, I installed a Redarc BCDC 1225 DC to DC battery charger in my trailer. This will step up the voltage so that you get proper multi-stage charging and management of your deep cycle battery. This particular unit can also attach to a solar array for solar charging acting as the solar charge controller.
A 10 gauge wire for charging should be fine. A Jeep is a short vehicle so the wire run length won't play into voltage drop as much as it would on a longer vehicle or a trailer with the battery mounted in the rear.
Now, if you want to keep things really simple and you will have less than 4 fused circuits at less than 30 amps each I highly recommend this. Blue Sea Systems Battery Terminal Block. You should inline fuse the charge wire as close to the Jeep's battery as possible and run that directly to the post of your trailer battery. The fuse block would then also attach right at the battery post providing fused circuits as close to the battery as possible for your accessories.