Various diagram

Normally mobile batteries have a lifespan of 2-5 years under normal usage. But then we have to replace them. Nowadays there are cheap replacement batteries which cost no more than 1$. But these low cost batteries run only 6-12 months. What to do with the used batteries, which can’t be reused in mobiles?
Well, easy solution is to use the batteries in a circuit that requires less current. We can use them for LED lighting. Thus your automatic lighting emergency light is ready which runs by your waste Mobile Battery. 

 

 

 

Source by : http://www.extremecircuits.net/2012/08/hacks-and-mods-reuse-old-mobile-phone.html