Asus has packed the FonePad with as many features as possible, all of which would be rendered moot if the battery life fails to live up to expectations.
The Taiwanese company has fitted the FonePad with a 4270mAh battery. It's a larger model than the Nexus 7 and is calculated to take into account the 3G usage of the device.
Asus claims you'll get up to nine hours of use from the tablet with 720pHD video playing with brightness up at maximum and both 3G and Wi-Fi enabled.
The Li-polymer 16Wh battery is sealed in to keep the chassis as thin and light as it is. This means there's no option to prise off the cover and insert a replacement when you're spent, but considering how rare this option is on tablets, it's not a huge surprise.
One of the pre-loaded apps that arrives with the FonePad is the battery-bolstering Power Saver app. You can choose from three modes: ultra-saving mode, optimised mode and customised mode.
The first and second will eke out as much from the battery as possible by lowering screen brightness (still the biggest draw on the battery) and powering down apps. Ultra-saving mode will also disconnect from the network where possible to cut down on 3G drain.
Customised mode alters the power plan of the tablet depending on which scenario you're using. Unfortunately, we couldn't find any indicators of what scenario we were on, let alone how to change it.
Slightly more useful is the Power Usage Chart - found in the settings menu - that breaks down exactly which parts of the Asus FonePad are drawing the most power.
Our own usage testing of the FonePad pretty accurately mirrored Asus' 9-hour claim. We activated all connectivity (except 3G) and put brightness and volume to maximum then looped HD footage until the battery died. The FonePad managed 504 minutes (just under 8.5 hours) - an impressive result.
One of the biggest reasons to opt for a 7-inch tablet over a larger alternative is the portability, and battery life plays into this in a big way. The FonePad doesn't have any problems in this department and we recommend it if you want a bumper battery life.