funny charging experience...

Hey guys, my first post in this forum. I've been using my XPS 13 9350 for about a month now and I love it!

I had a weird issue pop up just now.. My laptop is plugged in 24/7 since I got it, it just stays on my desk. I havent moved it since. While using my laptop, I noticed the battery charge LED light up, which I never actually saw it light up before. I thought this was odd... since I never unplugged or lost power to my laptop, nor have I moved the charging cable at all for it to lose power momentarily. Anyway, I check the battery indicator on the taskbar it's down to 94% and charging, about 19 mins left for full charge.

What can cause this? Has anyone experienced this before? is this built into the BIOS or something, for it to slowly drain the battery and charge it back up to extend the life or something?

 

This. Depends on laptop model and make, it probably goes to around 90% and then back up.
If it would charge battery from 99->100->99->100 continuously it would "kill" the battery much faster.

 

As above, if left plugged in all the time eventually the battery discharges. When it drops below 95% the charger will kick in.

 

Cool, thanks for the info!!

 

When the battery is full, isn't the energy supposed to bypass the battery and go directly to the power supply system for the laptop?

 

Yes, did you have a point?

Sent from my SM-G920F

 

I read his post as saying that the battery discharges when it isn't charging, but instead of charging it back up again at 99% it waits til it's down at something like 90%. My point was that it doesn't need to charge the battery when it's connected to the charger.

Since it was a stupid question I guess what he was saying was that it sometimes drop to 90%, cause staying at 100% charge over time is bad for the battery?

 

The battery doesn't suffer memory effects and while they will quote it at 400 charges it should still do 800 50% charges with the same degradation (shown as wear level)
I doubt you will get 4000 charges from 90 to 100% and still have a good battery at the end but you can set charging profiles in the BIOS or using the Dell Command software.

 

The charging kicked in at 94%
I never saw this before in any of my previous laptops, which is why it was surprising to me. I did see this only once in a Macbook Pro, but it was an older model with a really old battery. I figured the battery must have been defective. My current MBP which I bought last year and which has been plugged in since then has not done this either, while I was using it.

I did a clean install of Win10 on my laptop and didnt install any of the Dell software, other than drivers and the Dell SupportAssist program.
Next time I reboot, I'll check the BIOS settings and see if I can find something.

 

The older core2duo macbook pros used the battery as a supplemental powersource during high wattage use as the (rather large) powerbrick didn't provide quite enough juice. If your battery was removed or dead, the laptop effectively shut down a core and ran on just one core...

 

Actually,. this is pretty standard behavior. Any battery will very slowly discharge even if it isn't being used, so eventually the charge level will go down. At which threshold it starts charging is something else. My XPS 15 is set to custom thresholds of 60% before it starts charging and it stops charging at 95%.

 

Very interesting. Thanks for that info!! I saw some interesting settings in the BIOS as well. I don't wanna mess with them though! I like the current performance and profile of my laptop