Good morning all, On 10/10/2015 5:07 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote:
I was thinking of doing the same a while back, and intended getting a UPS and adding a large external battery pack, so if the mains failed late at night, I could run the GPS receiver and a few other things overnight, and consider starting the generator in the morning. I contacted a dealer on eBay, who specilaises in UPSs. He told me that the smaller units with built in batteries will die if you put large external batteries on them.
Years ago, I used to work at a place that would give me all their cast-off computer parts, including old UPS'. I've taken probably opened up about 20 of them, from various manufacturers.
The problem is that most don't have good heat-sinking on the power transistors. One unit of a brand I can't remember, all it had for a heat sink was an aluminum bar! Clearly, it was only designed to be run for a small length of time.
(It's the same case for the transformers - on several removed transformers, I've tried to use them backwards to get 12 VAC from 120 VAC, and they overheat quickly at more than 50% load.)
If you add external batteries, likely you will overheat and fry the electronics as they get far hotter than they ever intended.
thanks much and 73, ben, kd5byb _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
