battery only charged up to 98%

[apbudha]

In Power Manager -> Battery Maintence it is set to 'Always Fully Charge (Start when below 96%; stop at 100%), yet it is only charging up to 98% after 3 cycles, as it shows in Power Manager. Is there a reasonable explanation for this?

[trekrema]

Batteries are not perfect, depending on the battery manufacturer, a brand new battery will be anywhere from say 95-100%. The initial charge when you first purchase a new battery or get a new laptop is very important. Never use a new laptop without following the directions for initial use (usually you need to charge the battery for 14 hours or so). This initial charge makes or breaks the batteries useful life.

[ryengineer]

Cells are chemicals, moving parts that require adequate amount of initial chrages:

New batteries:
When purchasing a new battery, you may find that the battery is at or near 0% capacity. This will be due to the length of time the battery has been in stock and does not affect the quality of the battery. If the battery is at 0%, it may take up to 12 hours of continuous charging or, cycling the battery three times (see the Battery conditioning section below) to wake up the battery. If the new battery still does not have a charge after having been charged for 12 hours or cycled three times, it should be replaced. Standard warranty on all ThinkPad batteries is no more than one year as stated in the Statement of Limited Warranty that comes with the machine or battery.

How to get the most out of your battery - ThinkPad.

[apbudha]

thank you for these very valuable responses.

another question though; the info on the sight says:

"Cycle the battery (fully charge, then fully discharge) three times."

^^Does this mean a deep-charge? , if so:

"Deep-discharge occurs when your ThinkPad system is used on battery power until the charge is at 0% (the system will automatically go into hibernation)."

and "Do not deep-discharge Lithium Ion batteries."

Then how are you supposed to condition a Lithium Ion battery, or what does it mean to fully discharge for a Lithium Ion battery if it isn't a deep-discharge?

[ryengineer]

You're mixing up information for Ni-MH battries with Li-ion batteries:

It is recommended that you deep-discharge your Ni-MH* battery every few months for optimum performance. Deep-discharge occurs when your ThinkPad system is used on battery power until the charge is at 0% (the system will automatically go into hibernation). At this point, attach the AC adapter and charge to 100%.

Do not deep discharge Li-ion battery, it's the very same type used by your X6x series thinkpad, I never discharge my thinkpad battery below 4% and would suggest you the same.

Some lithium-ion batteries feature an ultra-low voltage cut-off that permanently disconnects the pack if a cell dips below 1.5V. A very deep discharge may cause the formation of copper shunt, which can lead to a partial or total electrical short. The same occurs if the cell is driven into negative polarity and is kept in that state for a while.

Manufacturers rate the lithium-ion battery at an 80% depth of discharge. Repeated full (100%) discharges would lower the specified cycle count. It is therefore recommended to charge lithium-ion more often rather than letting it discharge down too low. Periodic full discharges are not needed because lithium-ion is not affected by memory.

Lithium and lead-based batteries do not require a periodic full discharge. In fact, it is better not to discharge them too deeply but charge them more often. Using a larger battery is one way to reduce the stress on a battery.

Discharge methods quoted from Battery University.