Running NEC UL on C-cell nicads

Dave, MRO1-3/C6, DTN 297-8251, 508 467-8251 14-Sep-1994 1332 ((no email))
Wed, 14 Sep 94 13:35:46 EDT

I finally got around to trying to run my UL on off-the-shelf nicad batteries,
and the results were very good. I used 8 clearance bin Eveready (TM?) C-cell
nicads (manufactured in '92) and they ran it for over 3 hours! (The UL was on
low processor speed and bright backlight.) This is compared to about 40 min on
either of its new NEC batteries.

Since nicads only put out 1.2 Volts per cell, I was starting at ~9.6V instead
of the 12V the UL is used to. The big disadvantage of this is that the low
battery light was on the entire time (no warning of actual power loss.) I
suppose I could use 10 nicads for a real 12V, which would probably add another
30 to 60 minutes of operation as well. I was going to use 6 alkalines (11.x
V), but they don't recharge well if you discharge them much (deep cycle
discharge = 0 recharge cycles.) This is according to my generic alkaline
recharger - the dedicated rechargables may be significantly better.

I think Caldor is selling Millenium (TM?) nicads cheap. I haven't tried them
but I guess they'll work as well. The Millenium (TM?) nicads have a lifetime
warrantee ($1.00/battery handling fee) and have a 1 hour fast recharge. This
yields a 3.5 to 1 operation-to-recharge ratio compared to the 1 to 35 ratio
(40 minutes to discharge/24 hours to recharge) for the NEC battery. I know NEC
claims their batteries charge in a mere 16 hours, but it always seems to take
mine 24 hours.

What I did was to remove the built in battery and plug in the juice from the 8
C cells into the DC IN jack as if it were the power supply. It ran games, word
processors, modem, etc. fine at low voltage, but my desktop couldn't talk to
it reliably with LAP-LINK (TM?) (the 'high' voltage probably wasn't above the
threshold voltage on the PC.) Of course, when it's next to the desktop, I can
always just plug it in!

Disclaimers: don't try this at home without ESD protection and the personal
blessing of Zeus.

Dave Brown