Todd Allcock <elecconnec@AmericaOnLine.com> wrote in
news:fuji0l$dt4$1@aioe.org:

> Good point- despite the "500+" recharge cycles a typical Li-Ion is
> supposedly capable of, I find them to be noticeably weaker after a
> year of daily charging. My 26-month old HTC Wizard just got it's 3rd
> battery recently. While the batteries I'm no loger using weren't
> totally spent, they fell below the "make it through a 16-hour day"
> threshold I require to consider them useable.
>

Here's yet ANOTHER legacy from the old Ni-Cd days. Li-Ion batteries
only discharged half way, then immediately recharged ASAP, will cycle
nearly indefinately, far longer than the life of the devices they are
in! There is no old Ni-Cd 500 recharge cycles on Li-Ion batteries. How
long they run is totally dependent upon how they are treated by the
users and how much load heating the engineers put upon them in their
device design.

Buy two identical devices powered by the same size Li-Ion batteries.
Run one of them like a Sellphone braggart, running it for days until
it's dead, then recharging it "when I get around to it".
Run the other one by plugging it into its charger every chance you get,
never leaving it in a discharged state for any length of time.

Test it for yourselves. Li-Ion batteries are FLOAT batteries that LOVE
to be immediately recharged from ANY state of discharge.

------------------------------------------------------------------

Your daily charging is very admirable. But, there's another dark side
to Li-Ion battery maintenance....

Inside every Li-Ion is a special IC timer that prevents you from really
killing the battery pack below about 50% of its REAL capacity because
deep cycling them simply destroys them. A 1000 mAh battery pack has a
2000 mAh set of cells in it. During the discharge cycle, the timer
measures the load current and acts as an amp-hour meter like the one on
the side of your house that runs both up and down....down during use, up
during recharge. UNfortunately, the battery pack ISN'T following the
IC's charge state curve, exactly.

Over time, several months of constant cycling, the IC's idea of what's
charged and discharged gets out of sync with battery reality. Lucky for
the battery it moves DOWN the real curve, not up into the overcharge
range. Li-Ion batteries must NEVER be overcharged or they EXPLODE
FORCEFULLY. (See Dell's exploding laptops for demo) This IC prevents
that. So, your device's charge point goes down, when the IC cuts off
the charging prematurely from reality....and it's discharged point goes
up, with the IC cutting off the device to save the battery way earlier
than necessary. You observe, correctly, the battery doesn't run as long
as it used to.

The solution is to cycle it hard just ONCE to reset the IC, which has an
algorithm built into it just for this purpose. About every 3-4 months,
run the device until the IC absolutely refuses to run any more. Even
cycling it AFTER the IC cuts it off the first few times is even better.
After the IC shuts it down, wait 10 minutes and power the device back up
until the IC shuts it down again, a further discharge. DO NOT LEAVE IT
DISCHARGED LIKE THIS FOR MORE THAN 10 MINUTES as it damages the
battery's crazy chemistry. When the IC refuses to let the device come
on any more, even for a minute, IMMEDIATELY plug the device into its
charger and LEAVE IT PLUGGED IN OVERNIGHT to get a full recharge. Test
the battery run time and you'll find it has been restored, saving you
$20 from the net or $90 at your Sellphone company for exactly the same
battery.

Li-Ions properly treated and RECHARGED IMMEDIATELY as soon as you can
recharge it, last for years!

DON'T DO THE IC RESET ABOVE ANY MORE THAN IS ABSOLUTELY NECESSARY TO
RESTORE RUNTIME. The less you do it, the longer the battery will last.
It costs you every time you do the reset, so don't make it a regular
habit until it really needs it!

Oh, and NEVER STORE A PREVIOUSLY CHARGED LI-ION BATTERY! If you have
spare batteries, SWAP THEM WITH THE DEVICE OFTEN! They have a very high
self-discharge rate and will simply destroy themselves sitting in your
drawer! I swap out the batteries at least once a week. DO NOT COME
HOME, SWAP OUT THE CURRENT BATTERY FOR THE OTHER BATTERY....BEFORE YOU
FULLY RECHARGE THE CURRENT BATTERY, leaving it in a stored DISCHARGED
state! No, no, no....do the swapout ONLY after the battery that's
currently being run is FULLY RECHARGED, FIRST, then pull it and put in
the battery out of the drawer, FULLY RECHARGING IT NEXT before you use
it. You can never recharge them TOO OFTEN.