Arfa Daily wrote:
"Terry Pinnell" wrote in message
...

The battery in My Sony DSC-P1 digicam is some years old now, but still
serving me well. Its NP-FS11 Lithium-ion battery has specs: Max V =
4.2 V; Nominal = 3.6 V; Capacity 4.1 Wh. Its charger has suddenly
expired, so I'm seeking advice on either getting to its innards and
fixing it, or safely using my home-brew DC power supply while I shop
around for a replacement charger. I'm a bit unsure of lithium-ion
requirements and tolerances, and as these batteries are pricey I don't
want to risk damaging it.

The charger is a model AC-LS1A and has specs:
AC IN: ~ 240 V, 50 Hz, 11W
DC OUT: 4.2 V, 1.5 A

Mains AC is reaching the charger OK, but at the output plug there is
no voltage, and DC resistance is off the 20M scale of my DMM, so
presumably open. The output cable is integral, cannot easily test for
continuity, but it *looks* OK.

1. What is best approach to get into the case? Hacksaw? Or any secret
spots to drill which might reveal screws?
2. Any 'obvious' causes?
3. Could I safely connect to a 4.1 V DC source from my bench power
supply? At what optimum current?

Any/all advice would be much appreciated please.

--
Terry Pinnell
Hobbyist, West Sussex, UK


Everyone seems to be worrying about charging the battery correctly, but the
very basic specs quoted for the charger may suggest that it is in fact just
a simple power supply, and that the charge control electronics are actually
in the battery - I've seen this before, as temperature is a significant
factor in Li-ion battery charging, and it's convenient to connect the
temperature sensor, buried in the battery pack, straight to the charge
control electronics, rather than to have to get the info out of the pack and
into external control electronics.

Some camcorder charger units that I've come across, will not output any
charge current, unless they ' see ' a voltage from a part discharged battery
pack, across their output terminals. I've had many such chargers across my
bench in the past, claiming to be faulty with no output, when in fact the
problem lies with the pack that they are trying to charge, having no
terminal voltage at all to get the charge cycle going.

Just a thought ...

Arfa



Good point- and it looks to be a 1160mAH capacity too- so maybe the
cheapskate should just buy another one before he blows himself up
http://www.ezbid2000.com/catalog/pro...products_id=36 and
cheap chargers are prevalent:
http://www.greenbatteries.com/bachforsonpn.html
As a rule, the Li chargers will not fast charge at terminal voltages
below 2.5V and temps outside 0-50oC.