[Noisebridge-discuss] lithium-ion battery questions

[Michael Shiloh]

I agree with this theory. The fuel gauge circuitry needs to be 
recalibrated WRT the new battery.


David Yao wrote:
> I think the sales person was speaking in term of using it in the laptop 
> until the laptop does its own safe shutdown, which is a safe discharge 
> for li-ion batteries. The computer ought to follow the norms for 
> protecting the battery in this case. I presume damage doesnt occur until 
> the battery is discharged beyond this OS shutdown point. Thus you should 
> be fine if you start charging soon after OS deems it time to shutdown.
> 
> A possible reason for his recommendation to cycle the battery like this 
> is that the OS/BIOS could need to re-calibrate with the new battery. 
> Going straight from and old, worn out battery, to a fresh new battery 
> can make the laptop's time-remaining estimation inaccurate. ie, laptops 
> supposedly re-calibrate the time-remaining with every charge-discharge 
> cycle, and so the calibration for an old battery can be vastly different 
> than what it should be for a new battery. Doing a full charge-discharge 
> cycle a few times ought to re-calibrate it.
> 
> That's my guess.
> 
> -
> DYao
> 
> 
> On Sat, Dec 19, 2009 at 8:28 PM, Michael Shiloh 
> <michaelshiloh1010 at gmail.com <mailto:michaelshiloh1010 at gmail.com>> wrote:
> 
>     I little suspicious advice. I think discharging completely is very bad
>     for Li batteries, so much so that they usually have a built in circuit
>     that cuts out at some threshold.
> 
>     If no one on this list is an expert, I can forward your question to a
>     friend who is quite an expert.
> 
>     M
> 
>     John Magolske wrote:
>      > I recently bought a replacement lithium-ion battery for my X40
>      > ThinkPad. The salesperson at Central Computers mentioned I should
>      > charge it to 100% and completely discharge it, cycling twice in this
>      > manner as an initial "breaking in" procedure. Would anyone know if
>      > this is appropriate for a lithium-ion battery? Battery University [1]
>      > recommends against discharging lithium-based batteries too deeply.
>      >
>      > Also, there are safety issues with lithium-ion batteries [2], so
>     I'm a
>      > little concerned that I might be taking more of a risk by
>     purchasing a
>      > "no-name" replacement rather than the official Lenova branded
>     battery.
>      >
>      > [1] http://www.batteryuniversity.com/parttwo-36.htm
>      > [2] http://www.batteryuniversity.com/partone-5B.htm
>      >
>      > TIA for any perspective on this,
>      >
>      > John
>      >
>      >
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