Modern mobile phone battery life tends to be measured in hours rather than days, but one US manufacturer has just announced a model that can run for 15 years from a single AA battery.

It’s called the SpareOne and maker XPAL Power intends it for use as an emergency phone that’s always ready for action — no matter how long it’s been left idle (as long as it’s less than 15 years, obviously).

The idea is that the SpareOne can be left in a car glove box or kitchen drawer without having to worry about the state of its battery — and since it runs of a standard AA, replacing a dead battery with a new one is still pretty easy.

Alan Cymberknoh, SpareOne Project Director at XPAL Power said: “SpareOne’s breakthrough technology provides an unprecedented lifeline during dire situations that require an emergency response. By operating on a single AA battery, SpareOne solves so many daily issues, serving as a simple back-up phone you can carry without worrying whether it’s charged or not.”

“It can be left in a car for emergencies, used by hotels who want to pre-program concierge numbers for guests, passed to your children or parents to maintain an open line of communication — it’s essentially designed to make and receive the most important calls, no matter what.”

The SpareOne has a talk time of 10 hours and can automatically transmit location data via the mobile phone network, making it useful for rescue situations where there’s no obvious landmark information.

The SpareOne will be available in the US later this year for $50 (around £30), but it’s a standard GSM handset that uses a SIM card and XPAL Power does plan to offer it for sale in Europe.