Cordless drills

[Cleggy]

I have a 12V Bosch drill which must be over 30 years old now, and still in excellent condition. I opened up one of the old Nicad packs and re-fitted it with three 18650 Li ion cells and that has proved to be a very cost-effective way of getting many more years out of it. I managed to build in a small digital voltmeter to give an indication of state of charge, and two terminals to provide 12V output; useful if I'm using a mini-drill on the car.