This is a simple soldering project with just a few connections required. We know you’re eager to get started, but don’t rush into it…most importantly, do not install the USB jack on the PowerBoost! We’ll be wiring to the PowerBoost directly.

DO NOT install the USB jack on the PowerBoost!


Cut two pieces of wire about 4 inches long. Our 30-gauge silicone stranded wire works well…or use 30-gauge wire-wrap wire or peel a couple conductors off a ribbon cable.

Strip about 1/4" insulation from one end and 1/8" from the other. Tin the ends if using stranded wire.

Tin the legs of the switch and solder the wires: one goes to the middle pin, the other goes to either of the two outer pins; the third pin is not connected.

For later reference: the switch is “off” when moved to the two-wires side.

Optional but recommended: heat-shrink tubing reinforces these connections so they won’t break off later. Use it if you got it!

Solder the other end of these two wires to EN and adjacent GND pin on the PowerBoost (near the Adafruit logo).

Polarity doesn’t matter here; either wire to either pin.

Wires should be above the board; let’s keep the underside as flat as possible.

Power Wires

Cut two pieces of thicker wire (20 gauge is ideal, but a little smaller is OK) about 4.5 inches long. Use different colors for + and – if you have it, else keep careful notes.

Strip 1/2" of insulation from one end of the wires, and 1/8" from the other end. Tin the ends if using stranded wire.

Using pliers, wrap the longer exposed end of the wires around two #4-40 x 3/8" metal screws to create little hooks.

Remove the screws afterward; we’ll get back to these later.

The other end of these wires solder to the + and terminals near the end of the PowerBoost board. (Not the mounting holes!)

As with the power switch, the wires should run above the board to keep the underside flat.


Trim ONLY the minus (black) wire on the Lithium Ion battery, keeping about 2 inches. Strip a little insulation and tin the end of the wire. Solder this to the PowerBoost GND pin that’s between “USB” and “Bat.”

Make sure the power switch is in the OFF position before continuing.

Cut and solder just ONE BATTERY WIRE AT A TIME, else you risk an electrical short…this battery packs a wallop! One at a time, please.

Now repeat with the plus (red) wire. Cut to 2 inches long, strip, tin end and solder to the PowerBoost BAT pin.

If you accidentally make a solder bridge between GND and BAT, pull the wire out quickly while the solder’s still molten! Clean up the solder on the board and try again.

These batteries do feature short circuit protection, but that’s no reason to tempt fate. Handle every battery with respect!

Test It!

Cover the ends of the two power wires with some masking tape, or just be super extra careful that they’re not touching each other or anything conductive.

Try the power switch. The blue LED should turn on with the switch in one position, off in the other position. This LED indicates that the PowerBoost is providing 5V output. You can test with a multimeter if you like.

Plug in a USB wall charger. You should see a yellow LED indicating the battery is charging, or green if it’s fully charged.

If everything looks good, switch it off and you can then optionally clean up any pokey wire bits from the underside of the PowerBoost board.

Be careful not to bridge the BAT and GND connections when you do this. Trim one at a time, and don’t contact the other pin.


If you don’t see a blue LED when switched on, it can usually be traced to the following:

  • Check your soldering closely. There may be a bridged solder connection, a cold joint, or a clipped bit of wire cruft may have landed on the circuit.
  • Try the power switch in both positions.
  • The battery may be run down. Try briefy charging it.
  • The battery’s protection circuit may have triggered during soldering and didn’t reset automatically. Plug in a USB charger briefly and see if that revives it…you should see a yellow LED indicating “charging,” then try the power switch again and check for the blue LED.

This guide was first published on Jan 14, 2016. It was last updated on Jan 14, 2016.

This page (Soldering) was last updated on Jan 11, 2016.

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