I was having few old laptop batteries in my junkyard therefore I have decided to make some use of those batteries. Normally laptop batteries are of 3.6 to 4V rating therefore I have searched a LED strip from market here in Pakistan those LED strips are very common and easily available therefore I have selected a strip of 18LEDs, such strips are available for 20 cents (20 Rupees) from Pakistani market.
Now I have purchased Nokia battery charger socket a charging indicator LED and a switch and a diode all those spares are available for 10 cents (10 Rupees)
So if you have old laptop batteries you can construct this LED light just for 30 cents.
Circuit is very easy
1. just connect battery with LED strip via switch
2. Connect charging socket with battery via a diode
3. Connect charging indicator with LED to charging socket.
Your Extra Bright DIY Light is Ready