You don't have [an old charger], an old battery , a white LED bulb , or two or three , 10 ohms one watt resistor , any switch one. : This is an LED lamp available in the market for only two to three rupees , the lamp is better to buy white color. Since we will use it as a lamp , it is better to use a 10 ohm resistor color code brown black , one watt. Note that if you want to light the LED lamp, only one battery is a registered one and the same lamp goes on, but it is better to put a switch to turn off the lamp. Now let's see where to put the switch: After installing the switch, let's see how to do it when the battery is running out ? How to charge the battery with mobile charger , a few extra purses are used here , 1K resistor , a D1 normal rectifier diode 4007 or any other purse that is fitted only if the lamp is lit while charging the battery will indicate that the battery is charging.