Unit powers down when at about 85% battery life

Fully charge my Edge 1030, once the power drops to about 85% the unit powers down as if the battery is dead.  It's pretty consistent in that I can charge it to 90%+ and it works fine, but once it drops (I think the exact number is about 87%) it powers off.

Has anyone had this happen? Maybe the battery needs replacement, which I hear isn't easy to do?