GLOBAL – How long do five battery bars last you? Or two? It’s difficult to tell and really depends on your mobile phone usage. But there’s now a way to see just how long that one remaining bar is likely to last. Nokia Battery Monitor is available from Ovi Store, so read on to find out all about it.

It’s annoying when you wake up and realise you’d forgotten to plug your phone in to charge the night before. We’ve all done it. You then try to work out in your head, how long your phone will last before you’re adrift from the network, leaving you to rely on the work email for communication, but hope you don’t get caught.

Nokia Battery Monitor has been developed by Nokia and VTT Technical Research Centre, in Finland. With Nokia Battery Monitor, you’ll be able to see, in really simple terms, how long your phone has left before it decides to call it a day and goes to sleep on you.

There are three tabs at the top of the page once you open Nokia Battery Monitor. Estimates, Statistics and Info. Estimates will predict how many more days, hours or minutes you have left in your phone and will even break it down further into Talk time, Web browsing, Active use or Music playback. Which means you’ll see exactly how much longer you’ll be able to listen to your favourite band or how many minutes you have left on a phone call before you’ll have to plug it in to charge again. Any one of these Estimates can be pasted to your homescreen as a live widget, to make it easier for you to view.

Statistics shows you how you use your phone on a day-to-day basis. You’ll see how much energy is used throughout the week and you’ll see the results in percentages. So you’ll know if you spend too much time, and therefore energy, on sending text messages for example. This is a good way of looking at your habits and is interesting if nothing else.

Info is a page that contains all the information on Nokia Battery Monitor, such as the app version number, app overview and how to uninstall it should you want to. You’ll also see that Nokia welcomes all comments and ideas on how to improve the app and you’re given an email address to send all your feedback. I think it’s great to see this sort of encouragement. If you think it needs work, tell them, but it helps to be constructive.

I installed Nokia Battery Monitor on my Nokia N8 this morning at about 8am after a full night’s charge, I’m now being shown I’ve got 1 day, 21 hours left of active usage at my current usage rate. 9 per cent of my energy usage so far today has been from the homescreen itself, so that’s probably the apps I have running on it and 18 per cent is from phone calls.

Note that the accuracy of the app might …vary. Mobile phone batteries do not discharge at a predictable rate. For example, if your phone has been on standby all day, then it might believe that it’s got a full day’s use left. If you then receive two hour-long phone calls, it was probably mistaken. Accuracy improves over time, though: it calibrates itself to your typical usage pattern.

Try Nokia Battery Monitor for yourself and download it from Ovi Store, it’s free and available for S60v5 and Symbian^3 devices.

I think you’ll find it interesting to see exactly where your energy is spent in your phone. What do you think of Nokia Battery Monitor?