Samsung Galaxy Tab S review

Battery life on the Tab S is impressive. You can get at least a working day out of it with pretty much constant use, and more like two under regular conditions. If you didn't play with it much at all, several days wouldn't be out of the question.

On the days I was testing the Tab S it had dropped to around 60% by the evening from a full charge in the morning, with the larger model having slightly more juice left in the tank.

That's a scenario that was repeated in our standard 90 minute HD video test — the 8.4-inch model dropped to 87% battery from a full charge, with the 10.5-inch model holding steady at 90%. Although the larger tablet has a bigger screen, it's working with the same number of pixels and has a larger battery installed (7,900mAh vs 4,900mAh).

The same TechRadar video test knocked the Sony Xperia Z2 Tablet down to 72% and the 2013 Nexus 7 down to 80%. It's not the most scientific measuring stick but it gives you a fair idea of where the Tab S fits into the market as a whole.

The ultra power-saving mode is worth a mention, something we first saw on the Galaxy S5. It turns Wi-Fi and Bluetooth off, switches to a greyscale mode and restricts you to only the most essential apps like the calendar and clock (you can add apps to this list if you want to). Should you ever go on holiday and forget your charger, it may come in handy.

With a battery level of 59% I switched on the ultra power-saving mode and was given an estimate of 30 days' worth of standby time. Even as an estimate, that's noteworthy. The technology inside the Tab S screen — where black pixels don't draw any power — certainly helps here.

That's on top of the usual power-saving mode that dims the brightness, turns off constant syncing and disables Wi-Fi, Bluetooth and GPS. You can dig into these options and fine tune them if you wish to. It's a less drastic option, but it can help when you're trying to save power as much as possible.