Cordless drill require battery dismounted/mounted to operate

Thread Starter


Joined Jul 12, 2023

Greetings from Finland, my 1st post here.

At a cheap flea market i bought a quality Würth cordless drill. The drill works excellent but has a quirk.

After mounting the battery, the drill working led lights up and drill is usable. The led will go off after a minute of last drill turn. With led the whole unit dies. Battery removed, wait 5sec, remount and it is again good to go. Weird.

There is no mechanical in-built power switch at the lower drill body to the battery to cut off power without the battery (would not make sense anyway). The battery pack has new cells. Battery pack's only extra feature is NTC-resistor, which is ok.

I disassembled the drill. A tight packed small circuit board is at the bottom, no visible fails there.

I figured it would be enough to fool the logics to see the drill is used all the time when battery mounted. I guess the motor is driven by PWM. After working the battery could be removed, yet dismounting/mounting while working is PIA.

Any ideas what to look for and fix. Alternatively what would be a low current consumption smart way to make the circuit board see drill is in use when not.

Thanks in advance.

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