"Mika" wrote in message ...
On Sun, 2 May 2004 10:55:17 -0400, "Doug Dotson"
wrote:

I guess I had better move my entire breaker panel into the
battery compartment then. All my equipment is protected with breakers.

No, just put a large "main" fuse near your battery and that will
protect in case there is short circut.

Of course. I have an 800A T1 fuse close to the battery.

Have your panel and circut
brakers the way they are now.

That would be "breakers".

Needless to say, make sure you have
your fuses in the positive lead.

It is better to have the large fuse in the negative line. It is just as
effective and is safer. Check out www.amplepower.com for
a good justification of this.

I have a large 20 A fuse near the battery: it would blow if there was
a major short circut such as my positive cable coming to contact with
ground potential. No need to replace that often, as individual
equipment have 2-5 A fuses in the panel.

Having the 20A in the negative line will do just as well. Hopefully you
will never have to replace it if the rest of the system is properly
designed.

Two fuses and several switches will add some resistance, but voltage
drop will not be a problem unless you are running something in
100..150 Watt range.

The resistance of fuses and breakers is minor and of no significance
in most cases.

Other people have already posted warnings, and I would also like to
emphasize that lead-accid batteries have very low internal resistance,
leading to high short circut currents. It is possible to melt a wrench
or other tools if they come to contact with plus and minus terminals.

Nothing special about lead-acid. My AGMs and gels will melt a wrench in
pretty short order as well.

Almost twenty years ago I was in the Army (Signal Corps), and in field
exercises we run high power HF radios with car battery power before
AC generators were up and running. Could get on the air a few minutes
faster.. Anyway, this one guy managed to short circut a heavy cable
used to jump start cars. Poof, it vanished in a cloud of smoke. That
time we were glad we had gas masks on , that probably saved his
eyesight.

No kidding. Big batteries are to be respected.

Mike
OH1NZQ