I search for Android Wattmeter on the net for my eBike and found wireless Bluetooth COBOX Wattmeter for Android device and it is not so expensive.
http://www.cobox-ebikes.com/290/wireless-bluetooth-cobox-watt-meter-power.html
I wanted to know if anyone has experience with it?

http://www.cobox-ebikes.com/290/wireless-bluetooth-cobox-watt-meter-power.html
I wanted to know if anyone has experience with it?