[TenTec] DC Power Supply Backup

[WILLIAM MANSEY]

Hello Bill,
    I have the type of setup you are referring to.  I have a pair of Astron
35 amp power supplies powering my station.  I have a 12 Volt, 75 Amp/hr
battery "floating" at 13.8 volts across each supply.  You do not need such
large batteries - - - I just came across this pair of batteries at a
fantastic price.  These batteries are sealed Gel-Cells and I would suggest
that you use this type of battery rather than a standard motorcycle or
automotive battery as they give of gases much more readily than the sealed
ones.  A good source of batteries is one of those companies that deal with
motorized scooters for the elderly.  There are probably other sources as
well.
    Please visit my home page because I have information there concerning a
modification to the Astron power supply for this application.  My page is at
http://mysite.verizon.net/wa2pvk  If you are unable to get to my page -
please reply to me directly for more information.  Be sure to install a fuse
or circuit breaker between the power supply and battery!!!  THIS IS
IMPORTANT!  If (and this has happened to me) a surge trips the power
supply's over voltage circuit AND there is no fuse - things could get very
ugly.  ALSO - watch the initial current when you connect the battery.  Check
the battery's specifications to see what limits there are concerning maximum
charge current.  The current will initially be, potentially, rather high but
it will drop and level off at the float level pretty quickly unless the
battery is in a state of partial discharge.
    NOW that I have gotten that stuff out of the way - - - This is a pretty
handy arrangement.  Just take the time to do it correctly and you will be
pleased with the results.  (do it wrong and you will possibly blow the
regulator in the power supply, damage the battery, OR have a fire.)
UNLIKELY - BUT I would much rather err on the side of being overly cautious
instead of seeming to be complacent.  As I said; Please contact me directly
if you have any questions or comments.  73, Bill