"Peter Parry" wrote in message
news
On Wed, 01 Jul 2009 21:12:16 GMT, "The Medway Handyman"
wrote:

(I've re-ordered this to make the reply easier to follow)

To a battery layman like me, this is a golden nugget of information.
Makes
it perfectly clear which is which.

So, first of all, is it by & large all true?

Not really. To call NiMH "entry level" is sales crap to get idiots to
buy more expensive batteries. One advantage NiCd has over other
technologies is it is rugged and works better at extremes of
temperature.

NiCD (Nickel Cadmium). Entry level rechargeable battery which must be
fully
discharged before recharging. Failure to do so can reduce battery life.

NiMH and NiCd have very similar charging and discharge
characteristics. NiMH batteries often come with better quality
chargers and it is this rather than their fundamental characteristics
which make a difference. NiMH have a slightly higher charge capacity
than NiCd for a given weight.

NiMH (Nickel Metal Hydride). These batteries have no memory effect

Neither do NiCd.

therefore can be 'topped up' or charged at any time without affecting
battery life.

So can NiCd with the right charger.

NiMH batteries also tend to out perform NiCD batteries in high drain
applications.

Wrong. NiCd can have better high drain characteristics than NiMH. It
is a function of battery design not chemistry.

Li-ion (Lithium -ion). The newest battery technology for cordless power
tools, with no memory effect

Just like NiMH and NiCd.

they can be 'topped up' with no effect to battery life.

Not true, Lithium batteries have a finite charge cycle life and each
charge, whether partial or full eats into it.

The main benefit to this battery type is the weight - up to
40% lighter that NiMH batteries makes these the favourite for power tools.

They are not necessarily lighter, they certainly have a better energy
capacity per unit of weight so you can have the same weight and more
energy or the same energy and less weight.

If so, should we steal it for the Wiki?

I'd rather something a bit more balanced.

NiCd seem pretty rare now presumably because of recycling and Cd toxicity.

I'd have said NiMH are now the standard, Li ion started in phones etc and
are moving to tools, but at a price.

For individual AA cells in cameras and GPS, I get much better performance
from NiMH than NiCd, but some of that is almost certainly thanks to using a
better charger which does each cell individually. I agree with Peter that
chargers have got better anyway and that tends to help NiMH.

I don't know whether the often described NiCd "memory effect" is true or
not, but over time I've seemed to end up with more "bad cells" in sets of
NiCd than NiMH.