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Li-ion charger

I

ian field

Jan 1, 1970
0
Before I blow myself up - what is the simplest safe charger design for
Li-ion cells?!!!

TIA.
 
M

Mr. Wizard

Jan 1, 1970
0
ian said:
Before I blow myself up - what is the simplest safe charger design for
Li-ion cells?!!!

TIA.

Texas Instruments has Benchmarks line of gas guage and charger I.C.'s
for Li+ batteries. They are fairly simple to use and should save you
the trouble of blowing things up.
 
I

ian field

Jan 1, 1970
0
Mr. Wizard said:
Texas Instruments has Benchmarks line of gas guage and charger I.C.'s
for Li+ batteries. They are fairly simple to use and should save you
the trouble of blowing things up.

Not having accounts with any trade suppliers unfortunately limits me to the
rather meagre range of semiconductors stocked by Maplin - and whatever I can
skip raid!
 
M

martin griffith

Jan 1, 1970
0
Before I blow myself up - what is the simplest safe charger design for
Li-ion cells?!!!

TIA.
A plethory of stuff at Linear

BTW dont put a Sony label on it


martin
 
I

ian field

Jan 1, 1970
0
martin griffith said:
A plethory of stuff at Linear

BTW dont put a Sony label on it


martin

I wasn't going to put any label on it - why particularly not Sony?!

Besides - I thought it was Dell laptops leading the way in using Li-ion
batteries as incendiary devices!!!
 
M

Mark Fortune

Jan 1, 1970
0
ian said:
I wasn't going to put any label on it - why particularly not Sony?!

Besides - I thought it was Dell laptops leading the way in using Li-ion
batteries as incendiary devices!!!

Sony make the batteries for Dell and Apple laptops which have recently
been in the media recently for removing eyebrows.
 
M

martin griffith

Jan 1, 1970
0
Not having accounts with any trade suppliers unfortunately limits me to the
rather meagre range of semiconductors stocked by Maplin - and whatever I can
skip raid!
Get a RS or farnell account, fake some letter heads, as long as you
pay by credit/debit card no probs.

BTW where are you based?


martin
 
M

Michael A. Terrell

Jan 1, 1970
0
ian said:
I wasn't going to put any label on it - why particularly not Sony?!

Besides - I thought it was Dell laptops leading the way in using Li-ion
batteries as incendiary devices!!!


They were made by Sony, for Dell, but they have no indication that
they are made by Sony, unless you enter the code numbers on Dell's non
working battery recall website and it spits out a recall notice. All I
ever get is "Server not found", but I have at least one battery involved
in the recall. Sony also made the battery packs for Apple that are
being recalled. I've pulled the batteries out of all my newer laptops,
just in case.

BTW, on the TV news out of Orlando a couple days ago they reported on
a Dell laptop that caught on fire in the cab of a big pickup truck. The
moron threw it into the back of the cab where it set the truck on fire.
His excuse was that he just wanted to get it away from his daughter. I
would have either thrown it out the window, or pulled off to the side of
the road and set it off in the dirt to burn. Tourists!


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
C

Chris Jones

Jan 1, 1970
0
ian said:
Before I blow myself up - what is the simplest safe charger design for
Li-ion cells?!!!

TIA.

Go to the website of the battery cell manufacturer and get the datasheet.
If you don't put several cells in series but rather just use one cell, then
you should be able to get away with just a current-limited constant voltage
power supply, but some kind of redundant circuitry to disconnect the
battery if the charger develops a fault might be needed depending on where
the thing is being used. You must make sure that you don't charge the
battery above a certain voltage (about 4.2V but read the datasheet) nor
discharge it below another certain voltage (again see datasheet). If you
want to float-charge a lithium cell then the voltage is supposed to be a
bit lower than the value used for cyclic charging and discharging. You
should consider the likelihood and consequences of any component failing,
and I would choose to put the battery in a substantial diecast metal box in
case it catches fire anyway.

Chris
 
J

John Woodgate

Jan 1, 1970
0
dated Fri said:
Not having accounts with any trade suppliers unfortunately limits me to
the rather meagre range of semiconductors stocked by Maplin - and
whatever I can skip raid!

RS (in UK, not Radio Shack) will take credit card orders on the Web. So
will Rapid. Farnell will, but only for orders over a value which I've
temporarily forgotten. There are other suppliers, too. Get a copy of
'Television' magazine.
 
P

Philip Pemberton

Jan 1, 1970
0
John said:
RS (in UK, not Radio Shack) will take credit card orders on the Web. So
will Rapid. Farnell will, but only for orders over a value which I've
temporarily forgotten.

Either £20 or £30 for mail order, or £5 if you're going down to the trade
counter to pick it up. That £5 limit applies to cash-at-the-trade-counter
orders too, IIRC.
 
D

dt

Jan 1, 1970
0
How many cells, of what capacity/charge current and from what power
source (240v or 12v)?
David.
 
P

Philip Pemberton

Jan 1, 1970
0
ian said:
Before I blow myself up - what is the simplest safe charger design for
Li-ion cells?!!!

The Maxim MAX1811 - it's a single-chip 500mA lithium-ion battery charger. Feed
it +5V, add some decoupling capacitors and wire it up to a lithium battery.
Simple.
 
P

PeteS

Jan 1, 1970
0
ian said:
Before I blow myself up - what is the simplest safe charger design for
Li-ion cells?!!!

TIA.

If you don't want to use a pre-made charge controller, then here's the
standard charge method for _standard_ Li+ (but check the battery
datasheet from the mfr carefully)

Constant current (at up to the 1C rate) until the battery terminal
potential reaches 4.2V per cell. It's usually ok to charge Li+ in
series, but due to imbalance (especially in older batteries), it's best
to measure each individual cell for the 4.2V (The line of T.I. gas
gauges and chargers mentioned earlier do, in fact, do this).

Switch to constant voltage mode until the charge current drops below
some threshold (usually CCrate/10)
Stop charging.

Do not trickle charge Li+ (this can have spectacular side effects).

Cheers

PeteS
 
I

ian field

Jan 1, 1970
0
Get a RS or farnell account, fake some letter heads, as long as you
pay by credit/debit card no probs.

BTW where are you based?


martin

UK!
 
I

ian field

Jan 1, 1970
0
John Woodgate said:
RS (in UK, not Radio Shack) will take credit card orders on the Web. So
will Rapid. Farnell will, but only for orders over a value which I've
temporarily forgotten. There are other suppliers, too. Get a copy of
'Television' magazine.

Recently I heard RS had waived the requirement to be an account holder, so I
emailed them and they sent me the CD cat. As I wanted some LEDs I logged on
to view the data sheets before deciding which ones to buy and their system
refused me access! They ignored my email asking about this so I didn't
bother with them anymore!!!
 
I

ian field

Jan 1, 1970
0
Mark Fortune said:
Sony make the batteries for Dell and Apple laptops which have recently
been in the media recently for removing eyebrows.

Allegedly someone in Aus' described it as a "flamethrower"! - and going by
the photo of an unusually well illuminated conference room shown on the news
that's a fair comment!!!
 
I

ian field

Jan 1, 1970
0
Michael A. Terrell said:
They were made by Sony, for Dell, but they have no indication that
they are made by Sony, unless you enter the code numbers on Dell's non
working battery recall website and it spits out a recall notice. All I
ever get is "Server not found", but I have at least one battery involved
in the recall. Sony also made the battery packs for Apple that are
being recalled. I've pulled the batteries out of all my newer laptops,
just in case.

BTW, on the TV news out of Orlando a couple days ago they reported on
a Dell laptop that caught on fire in the cab of a big pickup truck. The
moron threw it into the back of the cab where it set the truck on fire.
His excuse was that he just wanted to get it away from his daughter. I
would have either thrown it out the window, or pulled off to the side of
the road and set it off in the dirt to burn. Tourists!


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

The Sony connection is something I should have guessed! From my monitor
repair days quite a lot of Dell monitors were Sony's in disguise. Quality
was either very good or very bad _ one model in particular had a tall steel
heatsink in the middle of the board which hit the CRT bowl if the base
flexed, Sony decided that the best cure was to glue a rubber block to the
CRT, this trapped the heatsink between the PCB and block so the PCB warped
and cracked!!!
 
I

ian field

Jan 1, 1970
0
Chris Jones said:
Go to the website of the battery cell manufacturer and get the datasheet.
If you don't put several cells in series but rather just use one cell,
then
you should be able to get away with just a current-limited constant
voltage
power supply, but some kind of redundant circuitry to disconnect the
battery if the charger develops a fault might be needed depending on where
the thing is being used. You must make sure that you don't charge the
battery above a certain voltage (about 4.2V but read the datasheet) nor
discharge it below another certain voltage (again see datasheet). If you
want to float-charge a lithium cell then the voltage is supposed to be a
bit lower than the value used for cyclic charging and discharging. You
should consider the likelihood and consequences of any component failing,
and I would choose to put the battery in a substantial diecast metal box
in
case it catches fire anyway.

Chris

Thanks - all good advice, the question was more general as pertaining to
whatever cells I might happen to come by, but one Toshiba pack contained an
array of Panasonic cells which have what might be part numbers stamped on
them, this might be a good starting point.
 
T

Tim Auton

Jan 1, 1970
0
ian field said:
Recently I heard RS had waived the requirement to be an account holder, so I
emailed them and they sent me the CD cat. As I wanted some LEDs I logged on
to view the data sheets before deciding which ones to buy and their system
refused me access! They ignored my email asking about this so I didn't
bother with them anymore!!!

By 'refused me access' do you mean it wouldn't let you have the
datasheets without logging in? That always was annoying, but I noticed
recently that you don't need to be logged in to see datashets any more.
Even before that, creating the required account was pretty
straightforward, even if it was a pointless inconvenience.


Tim
 
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