Electrical: Two batteries

[bezhawk]

I'm thinking of running two 6 volt Optima batteries in series as a 12 volt for space considerations when installing in a trunk. I plan on making a false wall and carpeting it . My question is will the charging system "see" this as one 12 volt battery, or will other considerations be needed?

[SN-60]

In series, the charging system will 'see' this setup as one battery.

[GinettaG12P]

A single cell of a lead-acid battery - even the spiral-wound cells in an Optima Battery - produces about 2.1 volts. In a 6-volt battery, three cells are connected in series, and in a 12-volt battery, six cells are connected in series. Thus, arranging two 6-volt batteries in series is exactly what a 12-volt battery does in a single housing, so the only difference would be a negligible increase in resistance due to the external wiring. Your charger will still see six lead-acid cells in series, just as it would if you had a 12-volt battery.

[53k]

I'm thinking of running two 6 volt Optima batteries in series as a 12 volt for space considerations when installing in a trunk. I plan on making a false wall and carpeting it . My question is will the charging system "see" this as one 12 volt battery, or will other considerations be needed?

The '63 Avanti I brought back from England in '85 was set up for two VW six volt batteries in the trunk, one on each side at the front of the trunk floor. Zero charging problems, completely invisible to the charging system.
Interestingly that change in battery location made a positive, noticeable change in handling.

[Mike Van Veghten]

No problem as others have said.

Just don't fall into the small cable hole...!
Use "0" cable for all connections. Also use the fine wire cable. Like welding cable wire, but there is automotive specific fine wire cable out there. It's a little more money, but well worth it. Also go directly from the battery to the starter, both the positive AND the ground cable. Then run smaller connections to the chassis components.

Mike

[TWChamp]

Also be sure the batteries are identical, that is both age and amperage, as well as size. If one battery is more amps than the other, the lesser battery will be overcharged and the larger battery undercharged. I'm sure you were plaing on buying two new identical batteries anyway, so this won't be a problem.

[Buzzard]

I am a little curious as to why you would need that much reserve power? I use 50+ 6 volt deep cycle batteries in my shop, connected with 00 welding cable so as to provide one very large 12 volt source for my 12 volt inverter. A single solar 230 watt panel provides most of the charging unless its raining, like today. Then its back to a generator for the supplement.
Bill

[bezhawk]

The 6 volt optimas are small, and I can place them on each side of the trunk, and not impact trunk space much. also it makes more sense to me to balance out the weight rather than having everything on one side. I haven't looked at the gauge of the wire, but it is larger than 1/2" conductor. Have the hot running along the drivers side, from the starter solenoid, and an equally heavy ground running up to a bell housing mount bolt. Also the regular motor mount ground, and a cable from a starter bolt to the frame.
I don't anticipate any problems.