🚀 go-pugleaf

In article <13662@optilink.COM> walsh@optilink.COM (Mark Walsh) writes:
>From article <1992Dec15.161824.7507@cc.gatech.edu>, by byron@cc.gatech.edu (Byron A Jeff):
>
>> I'm planning on using a battery pack with the D size batteries for a computer
>> I'm building.
>
>These babies are expensive.  For the D's, you are talking
>eight bucks each.  Why not just use a camcorder battery?
>RS has a cellular phone battery that is 12V, 2300mAH for
>forty bucks.  I bet that this would work well for a
>computer.  Does anybody know about the laptop PC batteries?

What you say is true. A couple of folks (Yo Jason and Dean!) have clued me
into a couple of possibilities.

1. Maxim Corp. makes an extremely cool voltage regulator series (the MAX722 and
   MAX723) That does the following: It'll regulate either a higher voltage
   (up to 9 or so) or a lower voltage (check this: Down to 1V!) input to
   5V at 200ma. So I can use only 2 batteries and this regulator to get 5V.
   It performs internal switching and charge pumping at 85% efficency. In 
   addition they also have a lower voltage mode for doing battery backed
   RAM or 3.3V chips.

2. Apparently we computer follks are looking in the wrong place. The real hotbed
   of NiCad activity is in hobby car racing. These folks have to deal with
   everything we've talked about and more: fast charging, getting the most
   power out a cell, not blowing up cells ;-)! So one side effect of this is
   the use of high current, fast charging Nicads. Here's two sources:

------------------- Begin Included Text ---------------------
Tower Hobbies 1-800-637-4989
or Sheldon's Hobbies: 1-800-822-1688
Ask about pricing on single D-Cell nicads, not matched or pushed, for
use in truck-pulling (they will know what this means). 
--------------------------------------------------------------

The best thing about Nicads Mark are that they are rechargeable. So a
high initial investment of $40 or $50 is amortized over years or use.
Also the high capacity D cells have twice the capaicty of the camcorder
battery. That means twice as long between recharges.

One last aside: The car hobbyists say that the memory effect is real. This
means that continued (<- important) partial charging and discharging of
NiCads will reduce their effectiveness over time. This means that it's
better to run the battery all the way down then recharge.

Later,

BAJ
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Another random extraction from the mental bit stream of...
Byron A. Jeff - PhD student operating in parallel!
Georgia Tech, Atlanta GA 30332   Internet: byron@cc.gatech.edu