Uhmm.. the answer to your question would be: copy the chinese charger - it has just 2 transistors and the voltage reference IC, it works only looking at the voltage, the finalizing charge current is unregulatet and is damw cheap to produce.

My charger seems big, ugly and with a lot of uneeded parts.. but they are are all essentials.

Voltage monitoring is done via a differential amplifier, current sensing involves just a resistor and NO opamps. Current control allow me to run this circuit with voltage from 9 and up. Removing current sensing (removing 1 resistor) makes impossible for the PIC to know or limit the charge current..

Disaply again, is just wired to the PIC, I can remove it straight on, but then it's like flying in the fog

It would be possible to remove discharge features, you'll save 1 transistor, 2 resistor and 2 caps.. again.

You could remove temp sensing too, but it's the *only* safety external loops/barrier available, I wouldn't do

Really, the cheapest charger is the one on the first page

By the way, I'm tuning it more and more and I'm taking out those false voltage reading when in charge caused by various contacts resistance that are causing increased sensed voltage.. I might.. build a board for it after all the work that's been done to now.

Still, I've to fix mAh metering :\