Introduction: Electric Drill Battery Charger

I was looking for a way to charge my Smartphone while on the go, I had looked at many battery packs, but none i had found gave me the mAh rating that i was after.

One day when charging my cordless drill batteries, i thought can i modify this to charge my phone instead of charging the drill battery.

I have two chargers for my drill, one large quick charge, and one slow trickle charge.

Parts :

  • 18V Cordless Drill Battery
  • 18V Cordless Drill Slow Charger
  • Car Cigarette Socket
  • USB Car Power Adaptor


  • Torx Screwdriver
  • Soldering Iron
  • Solder
  • Handy helper (to hold the board)

This guide shows you how i did it.

Step 1: Dis Assembly

Remove the 4 Torx screws.

Remember which terminal that connects to the battery is in which channel.

carefully remove the circuit board from the housing.

Step 2: Swapping IN and Out

Due to the nature of this charger there is a protection diode preventing reverse voltage.

swap over the wire from in to out and vice verse.

Step 3: Attach Car Cigarette Socket

Attach to the lead out of the board to a Car Cigarette Socket, The USB charger shown is a 12-24 V type and the battery is an 18V battery.

I haven't determined what the capacity of the battery is, but i have charged my phone (Moto-G) several times from flat while using it, without charging the Drill Battery.

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