connection from battery to drill?

Afterthought...

Servisol Contact Cleaner 200ml

Provides electrical cleaning and mechanical lubrication for contacts, switches and relays • Removes tarnish, dirt, grease, dust, oil and other deposits• Prevents arcing between dry contacts• Inaccessible areas are accessed by the extension nozzle supplied with the can• Supplied in a 200ml aerosol can

This might fix a switch problem but it will cost £4.99 to find out

It's solved problems for me...
April 2015

You have a difficult problem - as far as I know batteries are usually sealed - not made to be taken apart.

Your problem will be a poor connection one place or another - an intermittent open circuit in the battery itself - in the drill body or the switch - the switch has moving parts so it's a most probable cause. It will not be a short - a short will cause a fire - you would know about it.

If it were my drill I would give up on it - a successful repair is most unlikely.

Good luck...
April 2015