I've never had a problem driving my C11 all night (or even a couple of nights) with my $30 Radio Shack automobile jump-starter battery. It has a single cigarette lighter port, which is all I need, and it recharges by being connected to any household extension cord. No special external charger is required. I think it's rated at something like 12AH. However, I can believe that for people with CCDs, computers, dew shields, etc., more power is needed. So... take a look at the following: http://www.astro-nut.com/gel-cell.html If that battery (a really slick bit of home-brewed ingenuity) doesn't do the trick for you then you've really got to rethink your observing strategies. Seth -----Original Message----- From: utah-astronomy-bounces+sjarvis=slco.org@mailman.xmission.com [mailto:utah-astronomy-bounces+sjarvis=slco.org@mailman.xmission.com] On Behalf Of Joe Bauman Sent: Monday, April 30, 2007 10:54 AM To: Utah Astronomy Subject: RE: [Utah-astronomy] Portable power supply I'm very pleased with my Kendrick batteries. I bought a small one many years ago, then a larger version when I got a bigger 'scope. But both still work fantastically well and each seems capable of driving the telescope all night. The problem I've had is with keeping my computer and CCD setup going, which requirer AC. (I'll never be able to run a laptop for hours on batteries, I have concluded.) Plugging into my Jeep's electrical system quickly drains the battery, unless I keep running the engine -- and that seems to be bad for the Jeep. I recently bought a gas-fueled generator that was on sale at Pep Boys and can't wait try it out in the field. The huge drawback is that the generator makes a lot of noise so I have to go off by myself to do astrophotography. -- Joe _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.utahastronomy.com