Adding a second battery

[alanmalk]

Originally Posted by strawbarry

Alan,

I assume you mean a sealed lead acid battery, every lead acid battery generated hydrogen gas as it is charged. The higher charging current the more H gas produced. As long as the battery is sealed the gas is contained. The seals around the post are fragile and can be damaged when tightening the connections.

My intended Escape batteries will be the sealed lead acid batteries similar to the upper battery in the photo. Yes, they produce gas but at the levels of charging that will be typical in the trailer, all the gas will be contained in the battery - assuming I am careful with my connections.

And, to put another rumor to rest: In the photo I have two batteries, one top quality group 34 marine trolling battery, and one cheap Chinese 7AH all-purpose battery that I use for my depth sounder (under the meter). Both are SLA and both were last charged in mid-October after my last fishing trip (caught a good number of 20" rainbows, a very good trip). The batteries were not on float, just charged and ignored in a cold garage.

I hooked up the two in parallel, pos to pos, neg to neg, with the meter in the Amp setting. The initial current was about 30 milliamps and when I returned with the camera a few minutes later it was down to the 1 milliamp you see in the photo.

Conclusion: Very large difference in battery capacity, 75 AH vs 7AH, and used for very different purposes. Result - no current flow to speak of between the batteries. A battery charger, solar or otherwise should have no issues. Note: The little battery would have charging issues, but in the real world you would never parallel a 7AH with a 75AH and try to charge them both at the same time.

[tractors1]

Battery charge capacity doesn't make current flow. Difference in potential (voltage) does.