Peter Parry wrote:
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.
I'd assumed that ('entry level') to be true, because all of the 'super
deals' on DeWalt & Makita include low capacity (1.3a/hr) NiCD batteries,
presumably because they are cheaper?
ISTR that Makita with red NiCD batteries were at one time called Maktek and
offered as a lower cost alternative to a Makita with black NiMH batteries.
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.
Is that so? I've always believed NiCD did have a memory effect.
therefore can be 'topped up' or charged at any time without affecting
battery life.
So can NiCd with the right charger.
Is this the crux of the matter? Is the charger in some respects as/more
important than the batteries?
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.
This is what I'm after Peter, the choice of batteries is very confusing for
the average DIY guy, me included. I recently bought a new 14.4v NiMH 3.6
a/hr battery for my Makita DD because it seemed like a good deal. Truth be
told I didn't really know if NiMH was a better or worse deal than NiCD.
So, to rephrase my question, could we have a section on batteries (power
tool) in the Wiki to make matters clear for the battery numpty like me?
--
Dave - The Medway Handyman
www.medwayhandyman.co.uk