The battery life problem with iPhones isn't new for users who have long complained that their smartphones don't last as long as other phones. But Apple has always claimed that the iPhones' battery life is just as good as other phones in its league, at least that's what the battery life claims on specific models suggested. But Which?, the UK consumer advocacy group, decided to challenge Apple's claims and found shocking results.

According to the report published by Which?, Apple significantly overstates the battery life of its iPhones. The claims are made after testing nine iPhone models and Which? found that none of the Apple smartphones lived up to the official battery time claims made by the Cupertino tech titan.

In one example, Which? noted that Apple claims the battery life of the newly-released iPhone XR is 25 hours of talktime, whereas the independent investigation revealed the handset lasted only 16 hours and 32 minutes. This was the highest discrepancy of 51 percent noted in all smartphone models tested by Which?

Apple, iPhone 7, Made in India, Bengaluru, Wistron
Apple iPhone 7Apple Press Kit

Which? also noted that Apple's battery life claims are exaggerated by at least 18 percent. The method used by Which? for testing iPhones' talk time battery life was not revealed, which gave Apple the grey area to deny the claims. Apple's methodology for testing the battery life of iPhones is published on the company's official website.

"We rigorously test our products and stand behind our battery life claims. With tight integration between hardware and software, iPhone is engineered to intelligently manage power usage to maximize battery life. Our testing methodology reflects that intelligence," Apple was quoted as saying in response to Which? investigations.

Apple, iPhone Xr
Apple iPhone XrApple Event Page (screen-grab)

According to the report, Which? also tested phones from other brands and found that HTC's battery life claims were overstated by 5 percent. It doesn't fall anywhere close to 18-51 percent exaggeration by Apple.

On the other hand, some brands like Sony, Nokia and Samsung seemed to have understated the battery life of their smartphones. Sony's Xperia X5 Compact is said to have a battery life of 17 hours, whereas Which? found the handset actually lasted 25 hours and 52 minutes.

"Which? is warning people to be wary when looking at the expected battery life of mobile phones as they may vary from the manufacturer's claims," the body noted in its report.