Tag: power

Adding Five Volts portable power to your project

Thanks to the growth in portable battery options we can hack those “power banks” to make portable, rechargeable five volts power sources for your own projects.

We will be be hacking and comparing two different products that output five volts – a nicely packaged and made external battery pack for older Apple stuff and a new cheapie 18650 powerbank.

a diagram for the ages

Both products are basically the same.  It’s a lithium-ion battery with a USB charger on the front and a boost on the back to output USB standard five volts.  Some differences – the Apple power bank thing has an LED gas gauge to tell you how much charge it has and only starts outputting when you press the button.  It needs that manual button press to start feeding your project the five volts.  The cheapie 18650 powerbank does not need a button press – it’s switch is automatic as soon as you put a load on it, five volts are coming your way.  Also the Apple power bank has some battery protection circuitry in it to stop you from draining the battery to the point it’s damaged internally.  The 18650 powerbank has no such protection and you can kill the battery if you drain it all the way and then some.

pretty packagingLooks mighty pretty in it’s packaging, this was originally designed to be used with Apple products that had their original proprietary 30 pin socket.  Now that Apple has switched to a different proprietary socket everyone had to go out and buy new powerbanks, cables, etc.  Look on ebay for deals on stuff like this where time has moved on.


Let’s voltage outputsopen up the nicer power bank.  Grab a thin blade screwdriver and go to town.  This is an external charger that is rare in that it has a built in USB cable, not a micro socket you plug a cord into. Designed to feed five volts into the original Apple proprietary socket it is out of favor as Apple has switched to a different proprietary socket. Still, five volts is five volts. After prying off the shell with a screwdriver we can see the output side has three different wires.  five volts, ground and some strange Apple proprietary voltage.

We need to cut the old Apple socket offadded wires and solder in our own red and black to the five volts and ground connections.  At that point we have a portable,  rechargeable power supply that outputs five volts a the push of a button.   A little hot glue for strain relief on the USB charging cable and perhaps wrapping it in electrical tape so all the connections are covered.


The cheapie 18650 setup is even easier to hack.  On USB sockets the two outside wires are the power and on this one, it’s five volts and the right and ground on the left.  Knowing that and still putting a bit of color on the socket so we can tell which is which we solder wires onto the exposed connections.

Finally put them all back together again and start charging them up.  We now have two sources of five volts for a project, one with a manual switch and LED gas gauge and the other will give out five volts right away, no switch needed.   If you need five volts for your electronics project at AMT, come talk to me as I have a small supply of both kinds of powerbank available for member projects.