I would be very suprised if there was any noticable difference in voltage drop between stranded and solid core wire, presuming of course that the sizes were the same.

#12 AWG is #12 regardless of solid or stranded construction.

For a permanently installed 12 volt lighting circuit I would use standard house wiring cable, but a least one size larger than useual to reduce voltage drop.
Remember that a loss of one volt is trivial at 120 volts, but is nearly 8% of a 12 volt supply.

It is unlikely that vehicle wire will comply with the NEC for domestic installation.

Thanks for the info guys I`ll ask some friends about regulations and being sure to stay within code.

-Todd

You might consider evaluating Nickel Iron batteries rather than Lead acid batteries.

Nickel Iron has a lower surge power capability -- which is why the auto industry selected Lead acid -- but Nickel Iron is much more forgiving of deep discharge and improper charging.

And they don't off gas Hydrogen...

Thanks, I`ll check that out.

A little electricity 101.

With a 12 v system you need heavier duty wiring. Reason power equals voltage times current. As voltage goes down current goes up. For those mechanically inclined think of a hose. To pass more water you need a bigger hose.

Stranded verses solid wire. Electrical current actually passes along the outer edges of a wire. Above a certain level of current stranded wire if more efficient for the same size wire. For a simple lighting system it really wouldn't matter. But there is an actual difference.

Dolf cart batteries are what are called deep cycle batteries. They are designed to operate at a slow long term discharge rather than a high surge. Car batteries are made to supply a large surge to start a car. Deep cycle one are what you want for a power system. They will last much longer.

Hydrogen and charging. You are going to get it. But it is easy to deal with. Either put the batteries in a sealed room or containers. Think Rubbermaid totes. One not big enough. Use as many as you need. Drill holes to pass the wires through. Seal the holes with caulk or silicone. Run a sealed pipe to the outside.

Stranded wire is used for one reason in autos and mobile applications, it’s flexible and will not break as easily as a solid core wire. It can take bending and vibration better. The power handling ability of one over the other never comes into play as all that is done to handle more power is to go with a bigger wire, not to pick solid or stranded over the other because it takes more current.

Thinking about this I don’t think a sealed pipe will do much. Without airflow (an exchange of air with in and outgoing venting) the gas generated will not go anyplace.

Lead acid batteries should be outside; hydrogen is just too dangerous to be in the living area of a home.

The front compartment of our home on wheel is the storage location for the house batteries. They came in a plastic battery box with a screened hole in the bottom, and a sealed flexible hose from the top to an outside vent. Airflow...

Hydrogen is lighter than air. Even in a closed system it will rise up the vent pipe. But vent holes at the bottom would help.

<--- Thinking what can I do with hydrogen that is useful...