Laptop battery dies with 75% remaining

[daflyinggriffin]

I have an Asus G751JT that I purchased about a year and a half ago. It came with Windows 8 originally, which I upgraded to Windows 10 as soon as it became available. I had no issues until about 4-5 months ago, when it would turn off as soon as I unplugged the charger. I checked the wear on it, and there was only at ~20% wear. However, after purchasing a new battery online and replacing it, and reinstalling Windows, it was able to run on the battery again.

HOWEVER, I faced an even stranger issue at that point. Once the battery drops down below ~90%, it shuts off suddenly. If I try to boot it back up at this point, it loads until it opens Windows opens, and then shuts off again. I can boot up BIOS at this point and leave it on for a while, but then dies after about 30 minutes. The wear on this battery is ~13%, and it has a maximum capacity of 88 Wh and a current maximum capacity of ~77 Wh. The low battery level is set at 10%, and the critical battery level is set at 5%. I have tried re-calibrating the battery by letting it run until it dies and then letting it fully re-charge, but that obviously didn't take long as it shut off after ~15 minutes, and didn't fix the issue.

Trying to troubleshoot, I reinstalled Windows 10, which did not help. I then disabled ACPI, which I initially thought corrected the issue. It ran with Windows for slightly longer, maybe 30 minutes, and then shut off as before. It would then not turn on at all until I plugged the laptop back in, which makes me believe the battery was fully "dead" at this point. Upon loading Windows, I re-enabled ACPI, which showed that my battery was at ~75% charge.

TL;DR Got new battery, it dies suddenly at 90% charge in Windows, but runs longer in BIOS. I disabled ACPI, and it began to die instead at 75% charge, but then wouldn't turn on at all until I plugged it back in.

Here is the output from CPUID HWMonitor:

 

[basroil]

Bad batteries happen, just have it replaced.

 

[daflyinggriffin]

Bad batteries happen, just have it replaced.

Are you saying that the new battery I purchased was faulty?

 

[basroil]

Are you saying that the new battery I purchased was faulty?

Does happen, can't be sure if it's the battery or motherboard without testing it with a known working battery

 

[slyverine]

does the laptop run perfectly if you run it without a battery?

 

[daflyinggriffin]

does the laptop run perfectly if you run it without a battery?

It runs perfectly if I run it with a battery attached. The only issue is that it cuts off once it reaches ~75% charge while unplugged. Unfortunately, it is not especially easy to troubleshoot issues without the battery attached, since it is non-removable.

Should I try removing the battery to see if it still runs while plugged in?

 

[slyverine]

Nope , not necessary if it runs perfectly with the battery and charger on. Well 2 things i can think of first as mentioned by basroil a faulty battery. Second, iam not sure about this, maybe laptop gives false indications of battery health and computer thinks batery is dead and shutsdown.

 

[daflyinggriffin]

UPDATE: I had the laptop running in Windows without the power cord attached, and it ran for about an hour, all the way down to 70%. However, as soon as I attempted to open a few programs, it shut down. It doesn't seem hot whatsoever, and this laptop has a fantastic cooling system, but maybe it has something to do with the processing?

 

[basroil]

UPDATE: I had the laptop running in Windows without the power cord attached, and it ran for about an hour, all the way down to 70%. However, as soon as I attempted to open a few programs, it shut down. It doesn't seem hot whatsoever, and this laptop has a fantastic cooling system, but maybe it has something to do with the processing?

What you describe is current limited operation. Try these tests, from 100% to shutoff:
1) Turn on a heavy game and run it on benchmark mode (or in idle in game without doing much, not menu though!)
2) Run a movie, 1080p repeating (highly recommend MPC-HC)
3) Open word and just leave it like that
4) Leave the computer idling on desktop

If each one lasts longer, in terms of percent battery draw until failure (not time), then what's happening is that your battery or motherboard+battery can't handle the drop in voltage properly

 

[daflyinggriffin]

Thank you for all of the help!

I will test this out and report back tomorrow.

In the meantime, I will note that I observed that certain operations seem more likely to cause the laptop to shut down (i.e. loading Windows 10, opening up the Google Chrome application), whereas others seem to have no effect (opening additional tabs in Chrome, opening Word, streaming movies).

Also, if it's true that my battery or motherboard+battery can't handle the drop in voltage properly, would that mean a faulty battery could still be the cause?

 

[daflyinggriffin]

Confirmed. I had no issues playing games in Steam or playing videos in 1080p. However, when I re-boot Windows, or close and re-open the Chrome browser, the laptop shuts off immediately.

What does this mean?