On Sun, 6 Dec 2009 14:21:47 -0800 (PST), Mel Farrer wrote: >Most of the wall warts are just rectified AC. Very little if any >filtering.
We have a lot of power interruptions up here in the Santa Cruz mountains, thanks to storms, falling trees, and wild fires. Rather than buy a lot of commercial units, I have put together a bunch of little home-brew back-up power supplies for most of this gear. I simply find suitable batteries at swap-meets and use a wall wart as a float charger, with a parallel feed to the equipment. To avoid overcharging the battery, I carefully match the "normal" charging current so that current into the battery falls into the "trickle" range (5% -10% of the 10 hour discharge rate). This tends to work quite well. When power drops, our internet router, AC powered phones, Ethernet switch, etc. all continue to work just fine, even through relatively long outages. Likewise, my 12-14v ham gear runs on a couple of big Costco deep cycle batteries that are charged from a little 10A supply. Again, charging current is kept below that which could degrade the batteries. They won't run a big amp, but they do fine to keep K3s and a VHF rig running. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
