What do you plan to use for batteries? If you have some flexablity I would use four 6 volt golf cart batteries. Best bang for the buck you can get. You should be able to get 235 ah batteries for about $82.00 a piece that means with 4 of them (wired the right way) you can get 470 ah for about $400 after tax and cables.
Throw a 3 or 4 stage marine charger on it and you will have a real nice setup. If you have the money another nice thing you might want to get is a link 10 or link 20 by Xantrax. It will tell you the state of your batteries like you have never seen before. Vern On Tue, 16 Oct 2007 23:11:14 -0000 "ldgelectronics" <[EMAIL PROTECTED]> wrote: > Hello All, > > I have a requirement to install a battery backup system >at a local > ham repeater. It's a GE Mastr II running about 100 >watts. With that > much RF power, a couple of 100 AH batteries is only >going to last a > few hours. > > My first thought was to add a second lower power RF amp >(something > like 20 watts or so) and use coax switches tied to the >AC mains to > switch to the smaller amp when the AC power was out. >This should give > me a factor of 4 or 5 more amount of time on the backup >batteries. > > The second thought (and here is where I need input), was >to bring the > variable resistor (R8 on the VHF version) from the 10 >watt driver > board to a smaller external board. Then add a second >variable > resistor and a relay to switch between the two. This >should give me > two independent amp settings that can be controlled by a >single > control. > > Is there any reason why this should not work? It would >save the cost > of the second smaller amp and two fairly expensive >coaxial relays. > > The relay could be controlled from the repeater >controller or > automatically with just a 12v DC wall wart. > > Dwayne Kincaid > WD8OYG > >
