The Samsung S6 Edge in a New York Samsung shop on the day of its release in 2015 / Spencer Platt/Getty Images

The details were released in a hard-to-find Federal Communications Commission filing

Samsung's upcoming Galaxy S7 Edge could have 38 per cent bigger battery than its predecessor, the S6 Edge.

We already knew that the new Edge was going to have a heftier battery than the previous version, but the difference is much bigger than we thought.

As reported by CNET, a document filed by Samsung with the US Federal Communications Commission (FCC) shows that the S7 Edge has a 3600mAh battery - a huge 36.5 per cent increase over the S6 Edge's 2600mAh.

The FCC filing (click 'FCC ID Label and Location' to see it) is an official document that all companies must submit before they can sell their products in the US, and it's listed on the FCC's website, so there's a strong chance the information is accurate.

A larger battery would also make sense, considering the S7 Edge is expected to have a bigger screen than the previous version - 5.5 inches to the S6 Edge's 5.1 inch.

While much of the extra juice would go towards powering the large screen, Samsung fans can expect their S7 Edge to get good battery life as well.

We'll know for sure on 21 February at 6PM GMT, when the Galaxy S7 and S7 Edge are expected to be released at a Samsung unveiling event ahead of the Mobile World Congress trade show.