Andy Hall wrote:
It turns out that, to my mind at least, they've done it the most
expensive way possible, so much for shaving off the last few cents.

It has a fairly solid looking transformer rectifier power supply,
full wave rectification by the way, no corner cutting there. There are
then various indicator LEDs, a microswitch (with an external button to
press it) and a latching relay. There are *three* connections to the
battery, one of which is a temperature sensing one, when the
temperature rise indicating full charge is detected the relay is
latched off.

As I said, this surprised me, because it makes the charger relatively
complex. A crude rectifier and series resistor would be cheaper and
so would a delta/V detecting IC. As it is they have to have a
latching relay in the charger, three connections to the battery and a
temperature sensor in every battery. Certainly not corner cutting to
my mind.

This would all be a point if you were considering western component
costs and labour rates. The electromechanical components are very
cheap indeed and the labour rates to assemble them a tiny fraction of
western levels.

It *is* on a PCB, the latching relay is of the 'looks like an IC'
variety. The assembly costs of a charger with a delta/V chip instead
would be near enough identical, if not a little cheaper because there
wouldn't be the additional complication of the temperature sensor in
the batery.

The charger you describe could be put together by virtually unskilled
labour whereas as soon as ICs and PCBs are used, the game changes.

You're not seriously trying to persuade me that the PCBs, chips, etc.
used in 'expensive' tools aren't assembled in the Far East are you?

--
Chris Green