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XPS 13 9370 - Charging Question

Can someone else with an XPS 13 9370 verify this behaviour for me?

I have "Advanced Charge" mode turned on, where it will only charge the battery to 90% to prolong its long term life.

When using the laptop, once it's at 90%, it'll constantly flicker between "89% (plugged in - charging)" and "90% (plugged in - not charging)", roughly every 30-60 seconds. The white light at the front will continually go on and off in tandem. 

Is it normal that it keeps going down to 89% and needing to recharge to 90% when on AC power? I'm worried something will ruin the battery doing this all the time. I expected it to be able to run entirely off AC power without touching the battery.

Thanks!

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@CalmDownMonkey wrote:

Thanks for the responses!

I'm wondering though... why does the battery discharge at all when it's plugged in? Shouldn't it be running purely off of AC Power? If I'm not mistaken, the battery should go to 90% and just stay there.

 


That's why I used the term self-discharge.  The system isn't drawing from the battery, but batteries lose some of their charge naturally just by sitting around.  It can take a while, but it does happen.


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7 Thorium

It sounds like that charging profile specifies a maximum charge level but not a minimum charge level before it starts charging again. Keeping the battery topped up to 90% is better than keeping it topped up to 100% (where it would switch between 99 and 100% even if it doesn’t show that), but not as good as allowing it to self-discharge before recharging. I have my system set with a max charge of 80% and a minimum charge of 50%, so after reaching 80% it self-discharges over a few days down to 50% before charging again. The potential inconvenience of course is that I could end up disconnecting my laptop from the wall and only have a 50% charge. You have to decide whether potential day to day inconvenience is worth extra longevity.


Thanks for the responses!

I'm wondering though... why does the battery discharge at all when it's plugged in? Shouldn't it be running purely off of AC Power? If I'm not mistaken, the battery should go to 90% and just stay there.

 


@CalmDownMonkey wrote:

Thanks for the responses!

I'm wondering though... why does the battery discharge at all when it's plugged in? Shouldn't it be running purely off of AC Power? If I'm not mistaken, the battery should go to 90% and just stay there.

 


That's why I used the term self-discharge.  The system isn't drawing from the battery, but batteries lose some of their charge naturally just by sitting around.  It can take a while, but it does happen.


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2 Bronze
2 Bronze

Hi,

Long time no full charge will affect it's life too.

In fact,one battery's life can be charged up to 5000 times,it's over 10years, so i don't suggest setting like this,just make sure that not always full charge.


@samwonder wrote:

Hi,

Long time no full charge will affect it's life too.

In fact,one battery's life can be charged up to 5000 times,it's over 10years, so i don't suggest setting like this,just make sure that not always full charge.


Going a long time without fully charging the battery does not negatively affect the longevity of a lithium-ion battery, and laptop batteries are typically rated for a few hundred full charge/discharge cycles before they lose a significant portion of their charge capacity, not a few thousand.


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