I've been using my Razor Viper Wireless daily now for a couple of years. Over the last couple of weeks I've noticed the battery life being no where near as good as it used to be.
Today, from a full charge (94% as it no longer charges to 100%), the mouse turned off after 4.5 hours of use (RGB off, 1000hz refresh, using wirelessly).
I've seen a couple posts on here with the similar issue. Hoping there is a fix for the battery issue, if not it may be time to invest in a different mouse.