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

Li+ / LiPoly batteries should be charged in a constant current/constant
voltage scheme.

At initial charge, a constant current should be used, until the cell
reaches 4.2V. At this point, the charger should charge at constant
voltage until a threshold current is reached.

The current to charge with varies with battery. The C rate is usually
good. If the battery is 4.1Wh, then it's about 1Ah. 1A constant
current until 4.2V, and charge cutoff at 100mA would be a decent
solution.

It is very important to *not* let the cell be charged above 4.2V,
unless you want some interesting pyrotechnics.

See the http://focus.ti.com/docs/prod/folder...t/bq24103.html
BQ24103 and related devices at TI for an excellent explanation of the
charge cycle.

Cheers

PeteS

"PeteS" wrote:

Li+ / LiPoly batteries should be charged in a constant current/constant
voltage scheme.

At initial charge, a constant current should be used, until the cell
reaches 4.2V. At this point, the charger should charge at constant
voltage until a threshold current is reached.

The current to charge with varies with battery. The C rate is usually
good. If the battery is 4.1Wh, then it's about 1Ah. 1A constant
current until 4.2V, and charge cutoff at 100mA would be a decent
solution.

It is very important to *not* let the cell be charged above 4.2V,
unless you want some interesting pyrotechnics.

See the http://focus.ti.com/docs/prod/folder...t/bq24103.html
BQ24103 and related devices at TI for an excellent explanation of the
charge cycle.

Cheers

Thanks, Pete, just what I needed.

If I fail to access the case innards (or fail to fix it anyway), I'll
try that. Without a new design to incorporate a very sensitive voltage
comparator, I suppose in practice that means setting it to say 5V, 1A
initially and watching my DMM closely?

--
Terry Pinnell
Hobbyist, West Sussex, UK

Well, I would set a constant current to 1A and watch the voltage rise.
If you have a fully discharged battery, it'll be about 3V.

About 70% of the charge is done during constant current mode, so simply
shutting off the current source at V(batt) = 4.2V would work at a
pinch.


Cheers

PeteS

Terry Pinnell wrote:
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.

What kind of capacity spec is "4.1Wh"?

"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

The link I provided above is a charge controller I am using. It pulses
the output to 'detect' a battery (see if the voltage rises between
pulses). It also provides for a thermistor in the battery pack (the
ones I have utilise a Panasonic NTC, nominally 10k at 25C). On that
note, you should not try to charge a Li+ below about 0C or above 45C.

Li+ battery packs could have the charge controllers on board, but they
would be specials. Most packs come with the NTC and nothing else.

Cheers

PeteS

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.

"PeteS" wrote:

The link I provided above is a charge controller I am using. It pulses
the output to 'detect' a battery (see if the voltage rises between
pulses). It also provides for a thermistor in the battery pack (the
ones I have utilise a Panasonic NTC, nominally 10k at 25C). On that
note, you should not try to charge a Li+ below about 0C or above 45C.

Li+ battery packs could have the charge controllers on board, but they
would be specials. Most packs come with the NTC and nothing else.

Cheers

PeteS

Thanks all. I'll soon know for sure whether it's a simple or complex
charger, as I'm determined to open it soon. Meanwhile I'll experiment
with charging the identical extra battery I bought a year or two ago.
(Not such a cheapskate, Fred g.)

On my To Do List for a long time has been: 'Observe Sony charger
waveform'. That would have answered that point in advance of hacking
into the case - but regrettably never actioned! I strongly suspect it
*is* an intelligent charger.

BTW, the battery currently in the camera still has a charge, as it
successfully allowed me to transfer a score of recently-taken photos
and also take a few more.

--
Terry Pinnell
Hobbyist, West Sussex, UK

Fred Bloggs wrote:

Terry Pinnell wrote:
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.

What kind of capacity spec is "4.1Wh"?

Watt hours.

Graham

Terry Pinnell wrote:

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.


Here is a message containing pretty much all I know on the subject of
lithium batteries:
http://groups.google.com/group/sci.e...963123622c4d5c

Chris