Agreed. I've looked into several options and have concluded that trying to
build a DC powered PC power supply is not a very good solution, mainly
because of the large time expense and small efficiency gain. There are two
approaches which look attractive and each meets a different need. Note that
most power outages fall into one of two classes: either less than a few
minutes or else several hours to days.
One solution is to buy a UPS which will protect the system from short-term
power outages. At my home station I've done this and typical system
up-times for the computer and packet station have gone from a few days to
essentially unlimited. Although UPS systems are available with much more
energy storage, such as one designed to use an external battery, they are
probably way too expensive to be considered.
If longer up-time is required during power outages, a large deep-cycle
battery or bank of batteries will be needed. The most practical thing is to
run all the equipment directly off of the battery. Most radios use 12 V so
nothing extra is needed for them; for the computer buy a 12 V to 110 VAC
inverter. (Don't forget to either leave the monitor turned off or put it on
a transfer switch so it won't drain the battery when the power fails.) The
battery can be charged with an automatic charger, one that senses battery
voltage and switches between regular and trickle charge as needed. These
used to be hard to find but now have made it to the consumer market. I
found a charger and battery at a local discount store (K-Mart) for a little
over $100 and an inverter was obtained elsewhere for about $50. Note that
the total cost is no more than that of a heavy-duty 12 V power supply.
Jeff, k9ja
--- Jeffrey Austen | Tennessee Technological University gctzuzqj.ldccus@insight-com.com | Box 5004 +1-931-372-3485 | Cookeville Tennessee 38505 U.S.A.