16 Oct
2005
16 Oct
'05
1:53 p.m.
Subject: battery education sought
From: "Jay West" <jwest at classiccmp.org>
Date: Sun, 16 Oct 2005 13:30:35 -0500
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
I noticed my HP 262X terminals have a "Duracell TR133" battery in the back
to maintain settings when powered off. The battery indicates "Mercury" on
the side.
Extinct due to envromental concerns. Common use these days are the
3V lithium coin cells for the same uses.
Are mercury batteries rechargable? I would have thought
they'd use a nicad
or something to charge up while the unit was on.
Do not attempt to charge. Bad things can happen.
Mercury batteries were used for many reasons, high energy density,
extremely long shelf life at near zero power consumption and very
stable voltage over life. Lithium cells have replaced them in
most apps where battey drain is low and extremely long stable
life is desired.
The TR133 battery also indicates "4.2V". It
seems the Duracell replacement
for this battery is Alkaline, and 4.5V. Should I use it?
Jay
I'd expect that would work just fine. If your really uncertain add a shotkey
rectifer in series (Vf about .3V). My bet is the logic they keep alive
is a CMOS RAM and in operation that device Vcc is 5V.
Allison