Re: Battery Trailer

["Mark Hastings" <evblazer@softhome.net>]

    I had though about using a trailer for some more range on my
someday to be EV, without one it's relegated to a NEV. If one were to
use a battery trailer as a range extender would it be ok to parallel
the string in the vehicle with the string out of the vehicle if the
batteries were the same type but different size and/or state of
charge.
    For example say I have a 15 US8vgc for 120volts on board and want
to have a trailer with a set of 20 US145 6volts for 120volts to extend
my range.
    Would it be safe (i.e. healthy for batteries) to parallel them
while discharging and separate them for charging?
    Would it be possible to use lighter wire/connector for the trailer
since it would always be in parallel and seeing less amps?
    Or would a better way be to have a changeover contactor to switch
between the two sets of batteries. I would think paralleling the
batteries would be healthier since they would see less current .
However I don't understand batteries enough to know if putting
together different sizes and/or different state of charge batteries
would do more harm then good.

Mark Hastings
Silver Brook Systems, Inc