48v dc power

From: Bill Dawson <whdawson_at_mlynk.com>
Date: Thu Oct 12 16:32:58 2000

-> > > The worst problem about running power directly from the
-> car's supply is
-> > > that it's not a clean, steady stream of juice.
-> Computers run best on clean
-> > > power, and a car's power is anything but. Hence, the
-> deal of being grossly
-> > That's an understatement; voltage can fluctuate
-> > between 8 and 15V as different subsystems in the car
-> > are turned on; then there are spikes in excess of 100V
-> > induced by different systems; and then, if your battery
-> > contacts are less than perfect you can have 30VAC, rectified
-> > (or not, if the rectifiers fail in a particularly nasty
-> > mode!) from the alternator.


Reminds me of the time I took a 50 mile trip to my brothers in the Rover
88. When I arrived, it was dark, but all the lights on the Rover seemed
brighter than usual. Opening the hood, I noticed that the battery was
somewhat swollen. For some now forgotten stupid reason, I decided to
lift the positive terminal while the Rover was still running. Every
bulb on the Rover immediately exploded, although no other electrical
damage was done. Seems the alternator rectifiers went bad, which
damaged the regulator contacts. It was putting out well over 100 volts.
The battery was merely acting as a load, and when I removed the positive
terminal, POW!

Bill
Received on Thu Oct 12 2000 - 16:32:58 BST