Andy Hall wrote:
On 23 Oct 2004 17:43:21 GMT, wrote:

Andy Hall wrote:

NiCd and NiMH batteries can both be charged using the Delta V method
which involves monitoring the battery voltage very accurately to
detect the small voltage drop that occurs just after peak charge and
to stop the charging. With NiMH, the drop is about 2mV per cell, so
implementing chargers is not easy.

It's trivially easy with a ready made chip that does all the hard work
for you. They can be bought 'off the shelf' now. One off price is
only a dollar or two and I'm pretty sure they'd be a lot cheaper in
quantity. The most well known manufacturer is Dallas/Maxim.

Yes I know.

However, consider the impact of a dollar or two on the costs and
margins for a Chinese factory making a power tool that will end up in
B&Q for a few tens of pounds. The ex-works price is probably around
£10-15 tops so anything that does not need to be there is likely to be
left out. Every cent counts.

I knew you were going to say that which is why I added the bit about
"they'd be a lot cheaper in quantity".

The game is not quality, it is of meeting a minimal price and a
minimal spec. and having an acceptably low return rate within the
intended warranty period.

Yes, and what I was saying is that the chips are now so cheap that
it'll be no more expensive to produce tools with 'intelligent' fast
chargers and you'd get a gain in reduced returns etc.

--
Chris Green