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Re: Issue with notebook (maybe the battery?)



Hi, Tomás and Joe.

On 26/03/17 07:49, Joe wrote:

>>>> [snip]
>>>>
>>>> Checking the purchase invoices, I bought the notebook on September
>>>> 19, 2013, and then changed the battery on November 2, 2015. So
>>>> less than two years ago I have this battery.
>>>>
>>>> The notebook I use it practically every day and I leave it
>>>> sleeping from one day to the next so I do not have to open every
>>>> application every time. I'm not sure if that impacts so much on
>>>> the battery life.  

>>> If it was a long term degradation, possibly. With some battery
>>> technology/technologies(?) there is a "memory" effect. If there is a
>>> repeated "shallow discharge"/recharge cycle ( sleep overnight
>>> followed by running during day with charger plugged in) the
>>> effective battery capacity will decrease. IIRC that applies to only
>>> one technology but can't remember which.  

>> That would be the nickel family (NiMH and its predecessors). Laptops
>> changed long ago (I'd venture somewhere in the 90-ies) to Li-whatever.

> Lithium isn't particularly sensitive to state and depth of charge,
> apparently the optimal long-term storage state is about half-charge.

>> Those have other weak spots: overcharging shortens their lives,
>> especially being overcharged *and* higher temps. More overcharging
>> leads to fireworks. They *need* some electronics to take care of
>> that. Deep discharge is also fatal to their lifetimes.

> Complete discharge is instantly fatal, they can never wake up again.
> All lithium cells have rudimentary electronics to cut off discharge
> earlier than this, typically 2.8-3.0V per cell. Charging is relatively
> complex, constant current of about half capacity to around 4.1V, then
> constant voltage to fairly precise 4.2V, then when the current drops
> below a certain level, cutoff.
> 
> It should be possible to leave a lithium battery permanently connected
> to the charger. No 'trickle charge' will occur, no additional current
> will flow until the cell voltage drops by a certain amount. But full
> charge is not recommended for long-term storage.
> 
> Yes, I had to build a lithium battery into something a few years ago,
> I had to learn how to charge it. 

Thank you for sharing these interesting comments. I think some time I've
inadvertently consumed the entire battery charge (although this was
something that happened a long time ago, I think). Perhaps the
recommendation to avoid this is to check the "Enable Power Management"
option in KDE.

Do you think that of the information I showed in
/sys/class/power_supply/BAT0/uevent or
/org/freedesktop/UPower/devices/battery_BAT0 can be detected any
electrical problem with the battery?


Kind regards,
Daniel

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