text: Sending dozens of messages or playing games for hours can cause your phone to overheat, which can drain battery and even damage the device. Now an Israeli team of developers has built a 'thermal protection' case that not only warns you when your phone is getting too hot, it will automatically cool it down. Called Amited, the case uses micro-fans to blow heat away from the device, or can heat a phone using resistance coils if it gets too cold. Scroll down for video . The Optimal case (pictured) was designed by Israel-based Amited. Sensors in the case monitor the phone's temperature and if it gets too hot, Optimal will cool the device using two built-in micro-fans. And if it gets too hot, Optimal engages its Anti-Freeze protection mode to gently heat the phone using resistance coils . The recommended storage temperature for most batteries is 15°C (59°F), while the 'extreme allowable' temperature is 40°C to 50°C (40°C to 122°F). Studies have found that a phone is most efficient when it's between 0° and 35°C (32°F to 95°F), and keeping it as near room temperature as possible (22° C or 72°F ) is ideal. At an average temperature of 0°C (32°F), a lithium-ion battery will lose six per cent of its maximum capacity every year. At 25°C (77°F) degrees that number jumps to 20 per cent. Optimal syncs with a smartphone over Bluetooth and constantly analyses the phone's temperature when Auto mode is enabled, using built-in temperature and humidity sensors. Optimal syncs with a smartphone over Bluetooth and constantly analyses the phone's temperature when Auto mode is enabled, using built-in temperature and humidity sensors. The board and fans are pictured . Auto mode can be disabled and users can also manually track temperature changes using an app. This app shows  changes over time, but also reveals which apps in particular are having the highest thermal effect on the phone. Users can then set their own custom temperatures zones and set alarm thresholds . Inside the 0.19-inch (5mm) thick case is a pair of 'virtually silent', 0.07inch (2mm) micro-fans with air flow of 1.3 litres per minute. These dissipate the heat and cool the phone down. Amited is also fitted with an ultra-thin heating coils attached to the back of a conductive copper plate. When Optimal notices a drop in temperature, Anti-Freeze mode will engage these coils to stop the phone from freezing, even in sub-freezing conditions. Optimal's sensors are pictured. When Optimal's air vents are blocked, for example when the phone is in a pocket or bag, it will alert the user to warn them the temperature in their phone needs to be corrected. Alternatively, the phone can use Optimal's built-in battery as a backup . Optimal is fitted with temperature sensors, resistance coils and two 2mm micro-fans. It syncs with a smartphone over Bluetooth and constantly analyses the phone's temperature when in Auto mode. If it gets too hot, Optimal will cool the device using the micro-fans. These fans help the phone dissipate heat faster and cools down the device. And if the phone gets too hot, Optimal engages its Anti-Freeze protection to gently heat the phone using the resistance coils. Optimal remains in low-power, 'sleeping mode' the rest of the time to conserve battery. Auto mode can be switched off at any time, though, and people can manually analyse their phone's temperature, as well as see which apps impacting the device. Plus, when Optimal's air vents are blocked, for example when the phone is in a pocket or bag, it alerts the user to warn them the temperature of their phone needs to be corrected. Alternatively, the phone can use Optimal's built-in battery as a backup. Amited is launching an Indiegogo campaign to fund production of the case (pictured) on 9 April. Optimal will be available for pre-order for Apple, Samsung, Nexus, HTC & Xperia phones. Prices haven't been announced . Studies have found that a phone is most efficient between 0° and 35°C (32°F to 95°F), and keeping it as near room temperature as possible (22° C or 72°F ) is ideal. At an average temperature of 0°C (32°F), a lithium-ion battery will lose 6% of its maximum capacity every year. At 25°C (77°F) degrees that number jumps to 20%. Batteries exposed to hot temperatures lose their ability to store energy and the hotter the temperature, the faster they lose this ability. Extreme heatcan also cause permanent battery failure if exposed for long periods. In the cold, when the temperatures drop low enough, the phone could think its battery is empty even if it’s fully charged. The colder it gets, the least amount of energy that the battery can provide. In addition, the internal resistance of the battery grows, causing the output voltage to drop. When Auto mode is enabled, these subtle temperature changes are tracked automatically, but this mode can be disabled and users can manually track these changes using the Optimal app. This app shows temperature changes over time, but also reveals which apps  are having the highest thermal effect on the phone. Users can then set custom operation modes based on their activity and location, set their own custom temperatures zones and set alarm thresholds. 'Heat is the worst enemy of your smartphone battery,' said Amited. 'Like all electronics, constant exposure to the elements will have a negative impact on your smartphone. 'Intense usage will lead to overheating, while extreme cold weather will lead to some circuits freezing inside your smartphone. 'In time, these can affect the performance of your phone’s CPU, battery and GPU. And, eventually, they’ll let you down completely.' 'Optimal is the world’s first thermal protection case designed to keep your smartphone working at its best, no matter where you go or how excessive you use it.' Amited is launching an Indiegogo campaign to fund production of the case on the 9 April. Optimal cases will then be available for pre-order for Apple, Samsung, Nexus, HTC & Xperia phones. Prices have not been announced.
target: Sensors in the Optimal case track subtle changes in a phone's temperature .
  Micro-fans inside the case cool the phone down if it gets too hot .
  While built-in resistance coils gently heat the device if it gets too cold .
  Case is launching on Indiegogo this week, but prices haven't been revealed .