Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!pasteur!ucbvax!decwrl!jumbo!murray
From: murray@jumbo.dec.com (Hal Murray)
Newsgroups: sci.electronics
Subject: Running a Mac/SE from batteries and inverter
Keywords: Mac, batteries, inverter
Message-ID: <13671@jumbo.dec.com>
Date: 4 Apr 89 03:59:45 GMT
Organization: DEC Systems Research Center, Palo Alto
Lines: 19

I'm thinking about taking my Mac out into the field where there aren't any
power lines. Has anybody run one from batteries?

A friend has scrounged an inverter from an old ambulance. It says "square
wave output". I haven't put it on a scope yet. The Macintosh Family
Hardware Reference says the SE needs 85-135 V (rms), 47-73 Hz. I don't see
anything about the shape of the waveform.

I'd assume that the vanilla line => bridge => big caps power supply front
end would be happy with a squarish wave as long as it didn't brown out.
This type of supply normally only uses a small fraction of each half
cycle near the peak. I can't reverse engineer a power supply and convert
from rms to peak and guess the waveform from the inverter and ... all at
the same time.

Anybody know the answer and/or where to look/ask for more info?. Trial and
error could be expensive.

PS: Anybody know if the fan runs on DC or AC?