I recently got a Kospet Optimus Pro and wanted to be able to use it for online tasks while on the go (checking email, weather, etc).
But I found that turning on BT internet tethering caused a large amount of battery drain on the watch, even when doing nothing else (around 45% in 8hrs).
I decided to look for a way to have tethering only activate when the display was on.
After a bit of searching I found a thread on XDA that showed how to do just that via tasker.
Bluetooth Auto Connect
You need to install tasker and Bluetooth auto connect and then follow the instructions on the XDA thread to create tasker profiles to turn tether on and off.
I found it worked better on my watch with the initial wait time set to 5 seconds rather than 20 as suggested so that it is close to the backlight timeout.
After setting this up I only loose 13% over 8hrs (with the watch doing nothing else) and when I unlock the display BT tether auto-activates in a few seconds and I have internet access without the constant battery drain, or having to mess around in the BT menu.
I hope this helps others get better battery life from their watches