Ian Malcolm wrote:


Tim, I think you have a small problem . . .

So you've got the Aux battery fed off the engine battery via a diode.

This means that any load on the Aux battery will drain *BOTH* batteries
as if the Aux is lower than the engine current flows through the diode.
*NOT* what you wanted.

If you want to make this work, you'd need to reverse your isolator diode
plate and take the alternator output direct to the Aux battery.


Ian, you are absolutely right, and actually thats what I did. I was
thinking one way and typing another.

And I AM glad you called that to my attention.

And actually, I'm going to revam it some more.

you said, something like : Why don't you use a combiner(Isolater)?"

Actually, I'm going to make my own. A commercially bought isolator
(combiner) is actually

a three(for the most common) post device, which has "Alternator output"
on usually the center post, and "Bat.1" on another, and "Bat 2" on the
third. And this contains a couple heavy diodes to allow the alt to
charge simoaniously both battery banks, yet, leave the bateries
independant of each other. And that's a good idea.

The problem I have with the commercially made products, is that if one
diode diode goes out. Then the whole combiner, as you say, is bad, that
is, unless you wish to press the diode pac out of the finned aluminum
heat sink, and dig through the epoxy, and finally figure out that
you're fairly well wasting your time trying to repair the unit (that
is, unless it's made to be repaired), only to have to go buy another
one.

I have found that it's much easier to have two seperate heat sinks and
configure them to do the same thing as the commercially sold unit.

Reasoning is, that unlike the mounted commercial unit, which you
usually end up having to mount in some hard to get to place (like on a
small power boat), you can take your seperate heat sinks and mount them
anywhere you wish..tuck them in convenient places.

Also, if and when one goes bad, then thats the only one you need to
replace.

besides, I have a bountiful supply of these, just sitting around in the
junk.. LOL!

Thanks for your Input, Ian, I will check out the various threads.

Tim