"Jeff Liebermann" wrote in message
...
On Sun, 6 Mar 2016 18:04:58 -0000, "Ian Field"
wrote:

At the end of the day; that chip is a lithium cell charge controller.

Yes, with the added bonus of a puff counter and copy protection
system:
http://se.azinstall.net/2015/10/hacking-vuse-e-cig-puff-counter.html

Most of my home brew lithium chargers require supervision, the charge
board
from an e-cig can be left to get on with it - even if it takes a long time
to charge a decent sized cell.

I've been experimenting with fast charging 18650 cells at 4A. So far,
I've confirmed that I can charge at the data sheet rate without damage
but only if I keep the cell cool and not try to get too close to 100%

The ones I've been doing so far are basically a TL431 shunt regulator -
there are various ways to boost the current rating with external
transistors.

Nothing bad has happened yet - but I take care not to leave them charging
too long.

The current experiment is charging a 3x3 18650 laptop pack.

The charger is an 8uF wattless dropper on 50Hz, no safety circuits - so it
can only be on charge while I'm there monitoring it. 3 sessions so far, and
its only up to 11.8V.