On Mon, 15 Aug 2011 07:17:32 -0700, "Bob F"
wrote:

Hmmmmmmm. I peruse
http://www.streetdirectory.com/trave...vs_li_ion.html
and it sez longer (than NiMh) life cycles for NiCd.

I'm always suspicious of information sites that don't bother to supply
any numbers. This looks like a more useful comparison:
http://www.ka7oei.com/nicds.html
If you want authoritative reading, start he
http://batteryuniversity.com

If true, I'd likely be better off with NiCd. No?

You decide. It's not so much the chemistry, as it is how it's used.
See below.

It says NiMH has larger capacity, but NiCd has longer run time. You say what?

NiCd can handle more charge cycles. For NiCd, is you do everything
right you'll get perhaps 1000 charge cycles before the battery
deteriorates to about half capacity. For NiMH, you'll get perhaps 600
charge cycles.

Doing the math for typical batteries, NiCd will deliver:
0.7A-hr * 1000 cycles = 700A-hr
while NiMH will deliver:
2.0A-hr * 600 cycles = 1200A-hr
So, if you recycle your batteries when they're half dead, you'll get
almost twice the lifetime with a NiMH than with NiCd, where you need
to charge NiMH about 40% less often.

However, that's at best, under ideal conditions, with a device that
favors NiMH (i.e. no self-discharge problems and moderately high peak
current). If you do something non-ideal, such as charge the batteries
every day at the same time, you'll get 1000 days out of the NiCd and
600 days out of the NiMH which makes the NiCd the winner. NiMH is the
superior technology only if you charge the batteries when they're
almost fully discharged (at the knee in the discharge curve). If you
recharge by the clock, then NiCd is better because you can recharge it
more often.




--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558