On Tue, 10 Jul 2007 02:34:01 +0000, Larry wrote:

Stephen Trapani wrote in news:snwki.452
:

So I hook the alternator and AC charger to the common terminal of the
big battery switch, ditch the extra wire the PO had coming off of each,
and I have terminal 1 on the big battery switch go to the starter
battery and 2 terminal go to the house battery. Is that right?



There is a problem hooking it up this way. If you EVER screw up and plug
in the charger with that switch in the OFF position, the full open
circuit voltage of the battery charger, somewhere around 20-25 pulsating
VDC, will be applied to everything connected to the COMMON side of the
switch....without the battery regulating the maximum voltage of it. This
will blow every electronic gadget hooked to it on a live circuit....EVEN
IF IT IS NOT TURNED ON! Electronic gadgets use electronic switching, not
real power switches, those push button on gadgets. It will destroy them

So, I don't advocate doing it. I advocate using an isolator for both.
The diode isolators are fine. Connect the alternator to one and the
charger to another...SEPARATELY... There are 3 terminals....BATTERY 1,
BATTERY 2, SOURCE (the alternator on one and the charger on the other).
This will CHARGE both batteries from whatever charging source is running,
even both, WITHOUT inadvertently parallelling the batteries because one
of the diodes will be reversed biased when one battery tries to load the
other when running on batteries.

The other way to do it is with continuous-duty 12VDC and 115VAC
contactors available from auto parts places more cheaply. These look
just like a starter relay, except they have coils made for continuous
duty (always on).


Larry,

Re these 12 VDC continuous duty contractors available from the auto
parts with the capacity to carry starting amperage. Can you elaborate
a bit as I could sure use some of these..


A whole bunch snipped.




Larry

Bruce in Bangkok
(brucepaigeatgmaildotcom)

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