[VACList] Re:Optima (GEL) Battery

["Robin Leigh" <rgleigh@xxxxxxxxx>]

David,
    You need to be very cautious about connecting two or more batteries in
parallel. After some educational experiences in a sailboat some years ago,
we concluded it is better to avoid parallel battery systems altogether if
possible. Things learned the hard way-

1.    Batteries in parallel must be very similar in condition and
performance to avoid creating a situation where a weak or failing battery
drains a stronger neighbor. In practice, use only matched make/model/age
batteries in parallel, and maintain them carefuly.

2.    When connecting two or more batteries in a parallel bank, attach the
positive and negative feed wires to opposite ends of the bank, so that all
the batteries have the same number of wire connections. If you simply add
another battery to an existing one with two additional short jumpers, the
existing battery will discharge first because it has fewer connections and
less resistance.

3.    If you need multiple batteries, it is preferable to use a battery
isolator (basically a diode between the charger and each battery, to prevent
the scenarios described above) and a selector switch to draw current from
only one battery at a time. Consult RV or boat catalogs.

4.    A battery charge meter (a voltmeter that operates in the range 10 - 16
VDC) helps to see how the batteries are doing.

    Conclusion- one good battery and an up-to-date power supply are probably
your best bet. OBTW, it IS possible to overcharge a 105 Ah deep cycle
battery with a 10W solar panel.

    Good Luck,
    Robin Leigh '65 TW.