A sure sign of middle age is when you start to get nostalgic about the mobile phones of your youth. OK, those early models couldn’t do much compared with today’s smartphones. They couldn’t surf the internet, take pictures, play music or make you a cup of tea. But what they did have was a battery that lasted more than a few hours before the phone went dead. Scroll down for video . Modern life: According to a recent poll, nine out of ten people feel stressed if their phone battery run out. There’s even a word for it — ‘nomophobia’, the fear of being without a working mobile . My favourite phone of all time was a sleek silver Nokia 6310i from the early 2000s, which is still sitting in a drawer at home. It may be primitive by today’s standards, but it could run for 17 days on a single charge. Compare that with the battery life of a modern iPhone or Samsung Galaxy. Make a few calls, send a few emails, listen to some music and you’ll be out of juice by teatime. This week it was revealed that Sir James Dyson, inventor of Dyson hoovers, is attempting to solve the problem by investing £10 million in U.S.-based battery experts Sakti3. The 67-year-old entrepreneur is supporting the company as it attempts to double the battery life of our phones, electric cars and vacuums. Separately, scientists at Stanford University are hoping that their newly invented aluminium battery will revolutionise the industry with its ability to fully charge in under a minute. The battery will keep going for seven times as long as its lithium-ion relative, and can apparently withstand 7,500 recharges, whereas a conventional battery can take only 1,000. In the tech world, the battle for better battery life is never-ending. Earlier this month, Apple was left red-faced when it was revealed how quickly its new iWatch — which costs up to £12,000 — ran out of power. Sir James Dyson, pictured, inventor of Dyson hoovers, is attempting to solve the problem by investing £10 million in  battery experts Sakti3 . At the launch, Apple chief executive Tim Cook boasted that the device had a battery life of 18 hours. But it later emerged that using the smartwatch for phone calls or apps means it will die after three hours. According to a recent poll, nine out of ten people feel stressed if their phone battery run out. There’s even a word for it — ‘nomophobia’, the fear of being without a working mobile. And increasingly, phones come with built-in batteries that are almost impossible to remove without a degree in electronics. Apple started the ball rolling with the iPhone, and this month Samsung announced its latest model — the S6 — would have built-in batteries. So is there anything we can do to get more juice out of our phones? Nigel Linge, professor of telecommunications at Salford University, says the problem isn’t the batteries, which have improved immeasurably over the past couple of decades. ‘The reason why batteries lasted seven days in the 1990s is that a phone back then didn’t do a great deal,’ says Professor Linge. ‘It had a monochrome screen, made phone calls and sent the occasional text. It didn’t have apps, GPS, Bluetooth or wi-fi and it wasn’t used for Facebook. ‘If you take a modern phone and turn off all those things and just use it for phone calls and text messages, it will last a lot longer.’ The first mobile phone batteries were bulky, heavy and made with nickel cadium. They also lost battery life over time if they were not run down fully between charges, known as the ‘memory effect’. In the 1990s those early batteries were replaced by a superior version — nickel metal hydride. These didn’t suffer as badly from the memory effect, were thinner and quicker to charge. Today’s phones use lithium-ion batteries, an even thinner, lighter and even longer-lasting variety. How long they last depends what you do with them. Caught out: Early mobile models couldn't surf the internet, take pictures, play music or make you a cup of tea. But what they did have was a battery that lasted more than a few hours before the phone went dead . ‘One of the big drains is the screen — if people have the brightness turned up, it will run down the battery,’ says Professor Linge. ‘The other drain is the phone signal.’ If you are in a low signal area, your battery will drain more quickly because the phone has to work harder to stay in contact with the nearest phone mast. Phones also use up more of the battery if they are indoors, where signals are weaker. But Sunetra Chakravarti, from Mobile Choice Magazine, says there are simple things everyone can do to extend their phone’s life between charges. Turning off Bluetooth — the wireless system used by phones to connect to printers, laptops and other computers — will save your battery from running down. Switching off location services which use the phone’s built-in GPS tracker can also save power, as can turning down the volume of the ring tone and silencing any bleeps and clicks when you press buttons on the phone. ‘And make sure you have turned off any apps that are running in the background,’ she says. Keeping phones cool is also crucial: they work best below 30c (86f). So leaving them in the sun, or sleeping with the phone so it gets warm, will run it down faster. However, unlike the older style batteries, you don’t need to discharge modern ones fully before you top them up. Charging overnight shouldn’t cause problems, as modern phones and batteries have switches that stop the charging when they are full. Another way to get more out of a battery is to download the latest version of the phone’s operating system. Newer versions of the software used for Apple iPhones, for instance, let owners stop apps from constantly updating themselves with new information when they are not being used. Even then, you’ll still find major variations between different phones. That’s because some models are more efficient at making calls, surfing the internet or playing videos than others. When technology consumer website Expert Reviews tested the battery life of different smartphones, it found that the best lasted an amazing 14 hours longer than the worst. The Sony Xperia Z3 Compact kept playing a movie on a loop for more than 20 hours on one charge before it went dead — while the Nokia Lumia 620 managed just six hours and the iPhone 6 lasted just under 13 hours. Apple was left red-faced when it was revealed how quickly its new iWatch (pictured) ran out of power. It emerged that using the smartwatch for phone calls or apps means it will die after three hours . Other tests have found that the Xperia Z3 lasts on average 48 hours when used for five hours a day to stream music, make calls and watch videos. You may still need to replace a battery; a typical one will start to lose its ability to recharge after three or four years. But replacing batteries is becoming more and more difficult. Manufacturers are increasingly building batteries into phones so that owners can’t remove them. You can send your iPhone off to Apple to get the battery replaced, though it will take a week and cost £59 plus postage. And it is possible to do it yourself with a screwdriver and a replacement iPhone battery — available for around £15 on eBay. But it’s fairly tricky to pull off and easy to damage the phone. Some mobile repair shops will also replace batteries — and charge a lot less than Apple. The bright spot on the horizon is that it will soon take less time to charge up a phone. ‘Almost every manufacturer is bringing in faster charging, so with 15 minutes of charging you get four hours of talk time,’ says Sunetra Chakravarti. Sales of portable chargers are also booming. These slim boxes have to be charged in advance but are small enough to fit in a pocket. If your phone is running low, the charger tops up the battery. But until battery life catches up with the demands of modern phones, millions of mobile users will spend their life plugging in their phone to charge.
Most modern phone models have batteries that only last a couple of hours .
Problem isn't batteries, but amount of tasks mobiles are expected to do .
Battery life can be improved by turning off Bluetooth, sounds and GPS .