Dear Mr Rawles,

This letter is in response to the piece on using photovoltaics to charge batteries by C.K.. I feel I should spend some time discussing some potential problems with charging Lithium Ion ("Li-ion") batteries the way C.K. proposes. However first a few general notes.

- I am all for scavenging if you know what you are doing like some of us. But 'newbies' are better off not trying to disassemble anything more complicated than a desktop power supply for safety reasons as JWR pointed
out. I should add that the process that causes the 'bounce' after discharge also keeps some capacitors charged much longer than you would imagine possible.

Secondly if you only need some diodes or resistors, you can buy a batch of 100 for a few dollars on-line which will give you a lifetime supply.