BatteryFu is one of my first Android applications that I wrote to save battery life (and data) on my HTC Dream (G1) back in 2010. It has over 250,000 downloads!
Here are some great comments I got from users:
Pure gold !!!! Best of its kind. A battery saver that has no equal. This dev has raised the bar and is miles ahead of the wannabe competition with their high priced bloat ware. Bravo & thanks.
Awesome app Really works like charm. Its so small. I uninstalled JD. I have everything i need in this small app. JuiceDefender cant really defend itself against this app. Nice one
THE BATTERY APP To be the best, here we have the elegance and sleakness in just 70k. Unlike the competitors, all of which are around or over a meg!? Free shouldn't mean bloatware, this is that example.
I've since open sourced BatteryFu under the liberal MIT licence.