David Lang wrote:

OK, so we all know cordless power tool batteries have a limited life
governed by the discharge cycle.

What's the best way to prolong life? Discharge completely on a regular
basis? Recharge immediately after each use?

If you can do a full charge discharge cycle most of the time this will
help. If you start out with a good quality pack this is easier to do
anyway since the self discharge rate will be low, so you can use half
the charge, put the tool down, come back a week later and still use most
of the other half. Many of the cheaper packs encourage partial charging
on the grounds that you need to charge packs in an unknown state just
the be sure they will be ready when you want them.

Not overcharging is one of the most important things. With most NiCds
you can charge at a low rate (i.e. 16 hour charge) and not worry too
much about going over. Obviously this is not much use for a power tool
though - most people want faster chargers. The worst examples are the
"mid speed" ones - often these will charge in 2 to 5 hours and have no
control over the charging. These will kill batteries fast. A good
intelligent charger with delta peak detection and thermal sensors will
work best.

Don't run packs completely flat. Don't leave them flat for long periods.
Don't subject them to extremes of temperature.

And where does one get the individual cells from if you want to replace?

RS / CPC/ Farnell / Maplin / and any decent model shop.

Failing that send the complete pack to http://www.re-cell.co.uk/ and
they will rebuild it for you.


If you equip a poor or medium spec tool with a decent set of cells and
buy it a good charger (Makita and the like sell them separately if
required) you will not only get much better life from the batteries, but
also improve the performance of the tool by sometimes a very substantial
margin.

(I note that many budget tools have copied the same terminal arrangement
as used by Makita, since their chargers are universal and will typically
charge anything in the range of 7.2 to 14/18/24V (depending on model)
you can often use a Makita charger on these other packs as well)


--
Cheers,

John.

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