In article ,
Only Fair wrote:

I find the Energizer 2500mah double A batteries have major problem that
causes them not to hold a charge. When I require the use of these batteries
I find they are dead after only a few weeks of shelf life. The Energizer
2100mah cells are great with no problems what so ever and they have an
outstanding shelf life. When I called Energizer to discuss the problem with
the 2500mah, they deny any problems with these batteries and inform me the
problem is my charger. I have use 3 different charges and the problem
remains. I recommend no one purchase the Energizer 2500 mah batteries due to
their failure to hold a charge. I will never purchase Energizer batteries
again because the Energizer Company fails to support the customer. Has
anyone else have this problem?

I don't have direct experience with those specific models. However, I
have read (and noticed myself) that NiMH cells have a much greater
self-discharge rate than NiCD cells do. One source states that
typical NiCd batteries tend to self-discharge by around 10% per month,
that typical NiMH batteries are up in the 25%-per-month range, and
that there is a tradeoff between NiMH self-discharge rate and total
battery capacity. Self-discharge can be reduced, it seems, by
selecting the hydride material to improve hydrogen bonding, but this
typically reduces the battery capacity.

It seems likely to me, based on this reading and on what you report,
that the 2100 and 2100 mAH Energizer batteries may have been designed
and optimized for two different sorts of use strategy. The 2100s may
use a hydride with stronger hydrogen bonding, which would reduce
self-discharge and give a long shelf/storage life. The 2500s sound as
if they use a weaker-binding hydride, optimizing for the greatest
amount of storage capacity when freshly charged, but with a more rapid
self-discharge.

I've heard similar tales from a guy who makes extensive use of
battery-powered electric hand tools. In his application (occasional
use) he strongly prefers NiCd batteries, since he can charge them up
and depend on the tool still working in a few months. The NiMH
batteries seem to be preferred by people who use their tools
constantly, and need recharge them every few days anyhow - the faster
self-discharge simply doesn't matter for these folks and the greater
battery capacity is a win.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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