How do I connect the second battery

2oldman wrote:

dpgerson wrote:
will this make allow me to boondock longer? the reason I ask is that I had a truck camper with 2 batteries and the second didn't seem to make much of a difference.

The 2 batteries need to be similar in age and capacity. Just putting a newer battery in parallel with an old tired one won't help much.

x2. Need to use 2 batteries the same size and the same age. With 12v batteries, the amp-hours might be along the lines of 110, so you add 2 (or more) 12v batteries in parallel, and you add the total amp-hours together. (Parallel means pos to pos and neg to neg across all batteries.) As there are almost no true deep cycle 12v batteries, you can achieve the same thing by using 2 6v golf cart batteries, which =are= true deep cycle batteries, meaning that they can be deeply discharged and recharged multiple times without damage. A "regular" 12v battery is almost certainly going to be damaged if you discharge it below about 10v, for sure if you hit 8v. For about the same cost of 2 12v batteries, you can buy 2 6v golf cart batteries and a cross-over cable, and have a much higher level of confidence in how far you can discharge your batteries without damage. With 2 6v batteries, they are connected in series. POS on Batt 1 is the hot lead for your coach and NEG on Batt 2 is the ground for the coach. The NEG on Batt 1 is then connected to the POS on Batt 2 to give you a total of 12v. The amp hours of the batteries stays the same, however.

Lyle