Adding a 2nd battery

wintersun wrote:
Most important with a second battery is having both of the same type whether it is two AGM or two flooded lead acid type. Problem often is that the place where the second battery needs to go is not one that can be vented or where it is not easy to get to the battery to add water so the solution becomes to get two AGM batteries.

With the Torklift solution you could use a flooded lead acid battery which is cheaper and likely to last longer than an AGM type. If the isolator for the truck battery is under the hood then you can link the battery under the frame in parallel to the battery in the camper and both will be charged by the truck's alternator or shore power.

People tend to use much too heavy a gauge wire than is necessary and this adds to more cost, more difficulty in finding and attaching terminal connectors, and a lot more difficulty in feeding the wires from point A to point B. What is often not understood is that the current carrying capacity of the wire depends upon the area of its cross section and not the diameter of the cable. There are 12 foot jumper cables made using 8ga wire that work perfectly well.

For a 20 foot run for DC the use of 2ga wire results in a current loss of 0.53%. Using 8ga wire the drop is 2.15%. Seems like a lot at 4 times the drop but if you think about it in terms of charging time, the difference between 1 hour and 1 hour (60 minutes) or 61 minutes and twenty seconds with smaller wire is trivial. All you need is wire thick enough to handle the Watts being drawn so it does not overheat.

Big difference in ease in finding battery connectors for 4ga wire which is standard and for 2ga wire which is not in the car and pickup world. Even more choices with 8ga wire. Great source for wire and connectors is delcity.com or if you want marine grade wire, Jamestown Distributors.

This is a post to ignore - Your hard-e4arned money when buying an AGM battery means typically 2X the life due to major differnects is constructon. I am on my 3rd AGM battery and I'm not ever going back to 20-th century old-school lead-acid stuff...Do a bit of researech and join us...