Current Li-Ion chemistry is much improved from a few years ago, and self-discharge rates are a lot lower (hence the amount of charge left after 6 months).

It's fine to keep the battery in a drawer (cool/dry, of course) and charge every 6 months. They will probably last longer, but perhaps not for the reason you would expect.
You also have to accept that you loose the advantage of the built-in UPS-like behavior of a laptop with a battery, but if you have an external UPS, you may be OK with that.

For storage you actually want to partially discharge the battery (to 80%) before putting it away; Li-Ion has self-damaging chemistry at both 100% and 0% (whiskering and swell-cavitation), so you want to discharge to 80% before storing it, then charge back to 80% before it drops below 30% (typically 6-9 months, check it monthly to be on the safe side).

Recent systems won't "cook" a battery, the charge circuits automatically avoid overcharge, but any (commonly available) Li-Ion kept at 100% charge for too long will develop internal shorts due to the whiskering effect of high charge separation combined with corrosive internal chemistry. Whiskering does take a rather long time, however, typically 3-5 years for good quality batteries.

On 07/22/2012 09:12 AM, keith smith wrote:
>
> Sometime ago we discussed laptop battery life.� I asked the question about leaving the battery out and if that would extend the life of the battery.� I'm not sure that option was explored.
>
> Last December I took the battery out of my two lap tops.� I use both daily for about 15 or 16 continuous hours.
>
> I have been thinking the batteries might be fully drained by now.� Much to my surprise the newer laptop's battery was at 81% and the older laptop's battery was at 58%.
>
> Both are taking a charge.� After they are fully charged I will put them back in my desk drawer and charge them again in 3 to 6 months.
>
> I've have had poor performance from laptop batteries and did not want to "cook" these.� It will be interesting to see if this extends the life of the battery.
>
> Any thoughts?
>
> ------------------------
>
> Keith Smith
>
>
>
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