> so I thought of using a spdt relay with
>the coil connected to the AC that would connect the battery when
>the ac drops out. The advantage I see here is the circuit that
>connects the batteries uses no power and has no voltage drop
>while you are on batteries.
There are problems connecting batteries in parallel. See my previous posting.
>
>I have been working on a similar system to keep my rig powered when
>I loose AC. I use the relay to connect the battery to the charger
>while the AC is on (actually while my 12v power supply is on since the
>relays I am using have 12v DC coils), and to the rig when the AC drops.
>The radio doesn't seem to mind the momentary power glitch when the
>relay drops.
The computer might not like it, if directly connected, but the UPS should take out the glitch, if I understand correctly that you are using the UPS and just using the other battery to extend its life.
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Be nice. It doesn't take any longer.
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Charles Greene
Internet=anyibmg@n8it.org
Internet to Amprnet=slfhd@micro-link.net
115 Aaron Avenue
Bristol, RI (On the shore of beautiful Narragansett Bay)