DIY Cordless Tool Batt Adapter
I was given a number of broken Dewalt 6Ah + 9Ah battery packs from a tool repairer
From the 10 , I was able to make 6 good packs.
(These Flexvolt packs have 5cells x 3 in then. Typically 1 of the 3 sets of cells fail, so I swapped the cells from another pack)
Dewalt have no protection cut out in the pack itself so can be charged easily - 21v (4.2v/cell) using buck converter on a 24 battery pack
I only have Ryobi and Makita tools so made some of my own adapters from faulty Ryobi and Makita packs
Used the Dewalt 'travel' plate - broke the tabs and melted in some contacts - see pics
Soldered some decent wires (can reuse mains power leads) between the battery fittings and screwed them together.
Double check you have the battery connected the right way round and fits ok in the tools you are using
Ready Supply of Batteries
Just remember that the Dewalt have no low voltage cutout so keep listening for the motor speed slow down.
Packs also have very basic battery gauges on them to check.
Been running these packs for several months with no issues.