Ken wrote:
: I have been using a big switching supply for my shack. I intend to
: change over a to deep-cycle, flooded lead-acid battery if the grid
: goes down. It is, however, problematic operating a 13.8 volt radio on
: a lead-acid battery showing a voltage of 12 volts under load.

: I am thinking of replacing the power supply with a 20 amp marine
: battery charger that will automatically drop to float charge, charging
: a 105AH flooded deep-cycle battery. The battery would feed a "battery
: booster" -- a DC-to-DC converter that will maintain 13.8 volts at 85%
: efficiency. The booster would feed my equipment.

: Are there any drawbacks to this arrangement -- other than it requires
: a battery? The advantage is it won't boil the battery and will be
: immune to outages and brownouts. Also, it will do a fast recharge
: after an outage.
(snip)

How many amps is the "battery booster" rated for?

Astron sells something for similar use. Some of their power supplies are
available with the BB (Battery Backup) option. This is a circuit that will
float charge a battery, then protect the power supply when power fails and
the battery is called upon to power your rig.

I have this setup on my APRS WX station running 24/7. If commercial power
fails then the battery will take over. The computer running APRS will not
be powered, but at least the radio and TNC will still be up .. possibly
providing need network capability during an emergency. But, I'm running an
HT for a transmitter so it will work with less than 13.8 volts.

As I said above .. I think you should look into the possiblity of damaging
your charger if battery voltage is put into it the "wrong way"

Richard in Boston, MA, USA