[aprssig] OT - DC Auto Charger with auto cutoff

Robert Bruninga bruninga at usna.edu
Mon Jul 19 18:08:04 EDT 2004

>Because of a wreak in my van....
> I was thinking about putting a battery in the back and 
>running everything off of it.  Is there any device that 
>... would automatically shut off when full charge is reached?

Here is a tangential answer.  When considering operating 
mobile/portable do not overlook the DIRT CHEAP uninter-
ruptible power supplies that are showing up in junk piles 
and at hamfests.  Sure, they mostly have  dead batteries, 
but if you choose only the ones with a single internal battery, 
you get a NICE 115V AC power inverter *and* AC charger 
for a 12 volt battery, such as your car. 

Even at the Hamfest, after he jumps at your $5 offer for it,
say, "but only if it works".  Then as long as it is a 12v model, 
just hook it across his car battery. If it puts out 115v AC, 
then you got a good deal.

I found a bunch of 24 volt ones that ran off of two GEL
CELL batteries.  I just replaced the two batts with a single
larger 12 volt battey and hooked it in series with my car's
12 v and now I get twice the life from the original design.

Anyway, these things are everywhere.  At one hamfest
a company was selling a whole pallete full at $9 each
AS IS.  Factory returns.  Turns out, all that I bought
had NOTHING WRONG with them.  But apparently
the customers returned them because they didn't
"work".  But when you READ the label on the bottom
they say USER MUST CONNECT RED wire to 
battery internally  after purchase....  duh...

All of them had the red wire still in its original
short-free-wrapper...  go figure...


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