For a long time I’ve had old back up cell phones taking up space in my desk drawer. I was curious if I could put any of these old phones to some use. I can’t just throw them away so I decided to try and re-purpose one of them as a portable charger for my current smart phone.
Step 1: Materials
- Mp1405 5v 1a Lithium Battery Charging Board (Blue board)
http://www.amazon.com/gp/product/B00EXGFG42/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1
2. DC 3V to 5V 1A USB Battery Converter Step Up Module (Red board)
http://www.amazon.com/gp/product/B00C93Z8JY/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
3. SAMSUNG OEM EB-L1D7IBA 1850MAH BATTERY FOR GALAXY S II
(If you don’t own a Galaxy S II)
http://www.amazon.com/gp/product/B007PSBELE/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
4. 4 jumper wires ((2) 1.5 inch wires, (2) 2.5 inch wires)
Tools
1. Soldering Iron
2. Solder
3. Access to a 3D printer
Step 2: Circuit for charging portable battery
Insert and solder the two 2.5 inch wires to the B+ and B- terminals of the “Mp1405 Charging Board”. Each of these wires will be connected to their respective positive and negative contacts on the battery. The “Mp1405 Charging Board” is what will be used to charge the cell phone battery, and will feed power from the battery to the “DC Converter Step Up Module”. The Micro-USB connector on the “Mp1405 Charging Board” will be used to charge the internal battery of the portable charger.
Step 3: Circuit for charging smart phone from portable battery
Using a 1.5 inch wire, connect the OUT(-) terminal of the “Mp1405 Charging Board” to the IN(-) terminal of the Converter “DC Step Up Module”. Do the same thing with the OUT(+) and IN(+) terminals. The USB connector on the DC Step Up Module will be used to connect a micro-USB cable in order to charge a smart phone.
For more detail: Portable Charger for your Smartphone
