Alternate batteries

Mark Shields (TCHSHIELDMJ@CRF.CUIS.EDU)
Sun, 23 Jul 1995 19:16:24 -0500 (CDT)

7-23-95

Thanks for the replies on the whine--seems it is the nature of the beast.

I made up an external battery cable using a standard mini-DIN-8 male cable,
with 9V battery snap on the other end. It will snap onto one of the Radio Shack
holders for 8 AA cells (there are two styles). Very carefully observed
polarity. I used the pinouts that were posted to the list some time ago, and
checked everything three times!

Using either seven or eight cells (alkaline--1.5V each) the low battery light
would stay on--think the UL's internal circuitry "knows" something is wrong.
And each time you boot up, you get an error message and have to hit F1.
But it works fine. I tried seven cells because I wanted to see if it would
work. There is room inside where the old battery goes for seven AA cells. Will
have to fabricate a holder or find a slim one commercially.

I'm using Ray-O-Vac Renewal rechargeable alkalines. Have used them before and
they seem O.K.--don't claim to be rechargeable as many times as NiCads, but
hold about twice as much energy. Also, since they are 1.5V, they are the key to
running the machine on 7 cells. They are also reasonable around here--5 bucks
for four AA cells or 5 bucks for two D cells.

I got 55 minutes running the machine on 7 cells, using Spinnaker's Easy Working
Writer. Did not try anything else. Was on low backlight and high processor
speed--I value that for my purposes but sure it would have been longer at low
speed.

I also bolted together two Radio Shack D-cell holders and made a monster D-cell
battery pack that I put in my briefcase (I have a big briefcase!). I'm not
going to try to run it dead, but figure it should be good for 15 hours or so!
It has a snap connector like the 8-AA pack, so they are interchangeable using
my cable.

Another reason for using the Ray-O-Vac Renewals is that, like lead-acid and
NiMHy, they don't have a "memory" and so don't have to run them dead like
NiCads. This is especially important since the low battery light is now
useless--just keep charging them up every once in awhile and don't let them run
all the way down. I have noticed, though, that about 10 min. before the end,
EACH KEYSTROKE will make the screen dim noticeably. Warning enough.

Noted the three leads on the silicon hard drive backup battery. This is
probably a voltage tap so something inside can get 3.6V and something else can
get 2.4, etc. There is room in here for three AA cells, although they are a
little fatter than the original battery and you would have to just tape over
them or something. Radio Shack has high-capacity NiCads that are 850 mAh just
like the original.

Mark Shields
TCHSHIELDMJ@CRF.CUIS.EDU
"If we would teach children, we must first become children with them."
- Martin Luther