[Vwdiesel] Rabbit Batteries -1 or 2 ???

[Roger Brown]

gary wrote:
> ...
> Two auto batteries wired in parallel should not be a problem. Using two
> identical batteries does alleviate most problems.
>
> Something to consider, all batteries have internal resistance. I
> wouldn't be too concerned about overcharging one battery over the other.
> As the 2nd battery approaches full charge, its Vt rises, the difference
> between Vt and Vo becomes less, and less current will flow into that
> battery.
>
> Moreover, the problem of concern would be when both batteries are almost
> exhausted. Because each battery has internal resistance(never the same
> from one to the other), one battery could completely drain before the
> other, and would reverse. This is not good, and should be avoided at all
> costs.

This is why I have the solenoid separating the 2 batteries when the engine is off.  I can energize the solenoid manually, but
normal mode it to energize it with the ignition, that way I have 2 parallel batteries for starting, but 2 separate isolated
batteries for use in camp and for winching, etc.  Also have quick disconnects so I can swap main and aux. batteries in a few
minutes if needed.

--
    Roger