On Wed, 18 Nov 2015 18:10:28 -0000, "Ian Field"
wrote:

Nickel chemistry might be on the way out, precisely because of self
discharge.

An ever increasing number of cordless devices are appearing on the market
with lithium instead of nickel.

Yep, and there's a problem. If you charge to 100% and leave it there,
the LiIon battery slowly deteriorates. See Fig 5 at:
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
That's one reason you don't see any LiIon UPS/SPS battery backup power
system. There are plenty of retrofit kits and replacement batteries,
but nothing from the OEM's. Same with cordless phones, electric
shavers, and other devices that run permanently on chargers. About
the only way to do it is to use a battery that's about twice the
calculated capacity ma-hr, and only charge it to 50% of capacity.


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