by Phil & Ningning » Sun Oct 14, 2007 2:53 pm
First of all, it is assumed that the batteries are a matched pair.
The two six volt batteries in series simply power a 12 volt system and in use, behave together as would any 12 volt battery with increased capacity. You would connect the charging circuit as in any 12 volt system, with the positive lead of the charger to the positive connection on the battery, and the negative connection on the negative terminal on the other battery. No charging connection should be made at the jumper between the two batteries.
Think of your twelve volt battery as six two volters, or three fours, or two sixes. A normal automotive type battery is made up essentially of several two volt cells. 12 volt batteries have six internal cells connected serially, six volt batteries have three cells.
Hope this helps.