Ken wrote in message . ..
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.

Shouldn't be.

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.

I've been doing it for years. Except I don't use the dc-dc converter.
Voltage should not be a problem if you are constantly charging the
batteries.

It seems to me to be superior to the "PWRGate" (isolator?) arrangement
promoted by West Mountain Radio:
http://www.westmountainradio.com/PWRgate.htm

I think I can put together a system that will provide long-run, 13.8V
UPS to a 30-amp-max rig for around $175, not counting the battery.
Comments?

I only spent about $50 bucks for a 12/2 amp automatic charger. I ran a
battery and a 3 amp trickle charger for years using a ic-730. It will
keep up in most instances as you don't talk all the time. Neither the
730, or the 706 I use now have any problems with the slightly lower
voltage. Both are 100w radios. MK