GT 740m probably killed battery "ultrabook"

Wi RoZ · February 2, 2015

Hey guys,

I happen to own an ASUS S56cb "ultrabook" (specs below) and after a year and two months of pretty intense usage (university, random gaming now and then) the battery died. I checked the warranty and unfortunately the laptop has a 2 year warranty except for the battery: only 1 year. After some research I found out that the battery had 436 recharge cycles during it's short life span. When I scrolled through the Windows Battery Report I noticed something strange. The battery underwent a normal wearing process but in 1 day the maximum capacity had dropped from 37 Wh to 6 Wh (design capacity is 44 Wh, 2950 mAh). I thought that it would probably be normal, but it kept bugging my mind, so on a dreary Saturday afternoon I decided to determine what could possibly cause the battery to loose so much capacity so quick. I had been using the graphics card for a long time the days before the battery died (a bit of gaming, 3D applications for studying) so I ran a benchmark to see how hot the card would become before it throttled itself. Turned out it ran steadily at about 70 degrees Celsius and didn't throttle itself. Then I checked the specs of the battery again and noticed that the battery could handle a maximum temperature of 60 degrees Celsius before degenerating. This made me wonder if it was possible that the heath of the graphics card made the battery die. I found out that the card is positioned almost near one side of the battery, which strengthened my idea. Unfortunately I don't have a thermal camera to double check this.

So what do you guys think? Could it be possible that ASUS made a stupid design flaw here? I would like to know your opinions

Specs:

- i5 3317u (1.7GHz)

- NVIDIA GT 740m (810 MHz)

- 44 Wh, 2950 mAh battery

- 500 GB, 24 GB SSHD

- 8 GB 1600 MHz DDR3 RAM

Ostwind · February 2, 2015

The GPU will only make the battery hit that temp if the GPU is right on top of the battery, sure there will be an area around the GPU that is hotter but if the battery is outside that area then it won't be affected.

isteelsolz · February 2, 2015

I imagine they expect most users to use the integrated graphics the majority of the time. Sounds like you had it in discrete mode all the time, which would cause a higher average operating temperature , and more power consumption. Thus shorter battery life.

PaulKolby · February 2, 2015

I imagine they expect most users to use the integrated graphics the majority of the time. Sounds like you had it in discrete mode all the time, which would cause a higher average operating temperature , and more power consumption. Thus shorter battery life.

first of all, he said the battery doesnt even work now yes a discrete graphics card uses more battery but doesnt ruin the battery

second of all, he probably just used it for when he gamed

Wi RoZ · February 4, 2015

Well, thanks for your opinions guys! I do indeed think that the ultrabook wasn't mend to be used in discrete mode for a long time, but I still think it is strange. The graphics card is quite close to the battery and probably transfers heat via the aluminum housing. I don't know for sure of course, maybe I can get myself a thermal camera somewhere so I can measure how hot the little machine gets around the battery.