On Wed, 25 Nov 2009 13:48:00 +0000, PeterC
wrote:

On Wed, 25 Nov 2009 11:29:49 +0000, BD wrote:

On Tue, 24 Nov 2009 00:43:34 +0000 (GMT), Dave Plowman (News) wrote:

In article ,
The Medway Handyman wrote:
Do NiMh batteries self discharge if left unused for a period of time, or
is this just a myth?

They do - as do Ni-Cads. But by how much seems to vary wildly by make. Or
whatever. In other words you could have some which appear to take a full
charge and last ok when used near immediately - but discharge very quickly
when not used, as it were.

Newer ones will retain significant charge for up to a year. The ones that
come pre-charged are normally that type. Hybrio was one make, now
superceded by uniross ultra.

They are more expensive, but I find them useful for a backup set.

7-Day Shop is doing its own brand of these at a couple of quid less.

I saw somewhere a test that showed the 2100mAh hybrid cells outlasting NiMH
of nominally higher energy when used in a camera - can't remember the
details.


One factor AIUI is that some higher energy batteries eg Energizer,
have a high internal resistance, so it doesn't take long in some
instances for them to be unable to power the device they've been
installed in. I nearly threw away a digital camera because it would
only last a few seconds with new batteries. I bought even higher
capacity Energizers and it still would only last a few seconds. I
bought Sanyo Eneloops and it now goes for months.


--
AnthonyL