“14 hours battery life when Web browsing” is the claim made by Asus for the new Atom X5-based Transformer T100HA. Given the size and weight of this tablet (the keyboard doesn’t have an extra battery,) that’s huge. So huge that I don’t believe it. I’d like to believe it but my history of testing PCs based on Intel Atom processing platforms tells me to question it. I’ve done that below.
We don’t know the battery capacity of the T100HA but there’s little-to-no chance that Asus have managed to pack anything more than 36 Wh into this chassis. It’s fairly easy to work that out.
A 36 Wh hour battery running for 14 hours is an average 2.5 watts battery usage. The stars will have to align to achieve that figure – a screen backlight can take 1.5W at half-brightness alone.
The low reported resolution of 1280 x 800 will help reduce GPU power usage and it is possible to drop brightness to very low levels in dark rooms if you want to get super-efficient. If the tablet (the keyboard must be disconnected for the best efficiency) is close to a WiFi hotspot and turned to low power settings there are some savings there and if there are no desktop applications running a Windows system can be extremely efficient but I still very much doubt you can reach 2.5 W average drain in a ‘Web Browsing’ situation.
It’s possible that Asus have used the Edge browser (Windows Store apps are, in general, better than desktop apps in terms of efficiency) for this test, and done it so slowly that the system is effectively idle for 90% of the time.
OK, there might be a single case where it you can use a Transformer Book T100HA online, with one charge, for 14 hours but I challenge any reviewer to achieve it.
For the other million-plus cases you can forget 14 hours battery life. Given what we’ve seen on the Atom X7-based Surface 3 and similar Baytrail-T tablets you can expect a minimum of 4W of average drain under ‘normal casual’ usage…rising to 5W after 6 months when you’ve installed a bunch of programs that run in the background.
Asus Transformer Book T100HA battery life: 7-9 hours real-world online battery life, in my opinion of course! Naturally i’ll be very happy if i’m wrong because this would be a significant step forward in web-browsing efficiency on a 10-inch PC.
More information, images, links to articles and the specifications we know so far are in our database.