On Wed, Oct 28, 2009 at 8:36 PM, Rocket J Squirrel
<camping.elliott@gmail.com> wrote:
> I think that Loren's advice about being cautious about wiring dissimilar
> batteries in parallel is worth considering. it is Received Wisdom and one
> should not go against it without accepting potential ugly outcomes.
>
> But . . . not much is likely to go wrong if they are the same technology
> (e.g., sealed, AGM, gel, deep-cycle, whatever);

At least batteries in way dissimilar in condition should not be
connected parallel. I see no problem if they are at least "roughly"
the same kind and used wisely so that they would age anyways at the
same rate. So one thing that should not be done is trying to fix Your
van this way if Your original problem is a bad/old battery in a
system. This is where You are at least wasting the most of Your new
battery and might end up with 2 bad ones. The more similar You have
them, the better, to some extend at least.

Mixing deep cycle and ordinary car batteries would probably mean that
You are losing most of the deep cycle properties of Your setup as they
usually have basically the same technology, others just are rumoured
to be able to take more deeper cycles. Some do, no doubt about it.
Some AGMs and whatevers require different chaging voltage, and thus
different requlator in ones alternator than the normal one. And most
of them are extremely sensitive to high voltages, so they would burn
anyway in normal setting.

I guess it should be quite allright if they are supposed to be charged
with the same basic regulator, right ? (and afted the smoke clears, we
will check the connections?) And if You dont mind losing the
properties You paid for and taking care of different maintenance
schedules of the batteries.