Nikon coolpix L820

I bought this camera for my wife a year or so ago for family photos.... well she never uses it and its a bigger camera with 30x zoom so I'm gonna use it hahaha.. its a little too big for a scope mount I think. but it dose have a high speed video recorder at 240fps and I think 420 fps but it will only let me record 15seconds at a time. I put it on the tripod and tried to get some action on pest birds but with only 15secs to film its hard to work the camera and gun at the same time.. So what I guess I'm askinging is if anyone else has this camera and if theres a way to get more record time out of it. or if all high speed cameras only have 15seconds or so of video life???

I guess I could just use the regular camcorder but who wants that withoult slow motion ??