Cordless Rotary Hammer Drill Restoration and Battery Rebuild 7S60A


This tool is obsolete because it runs on old Nimh batteries. It was abandoned in Japan. Everything is fine except for the battery and the charger. I bought it to restore and want to know its quality.

All that needs to be done is to clean the internal parts, put in new grease, and especially make a new battery with lithium that has the same power as the old one. The original battery contains 20 of Nimh batteries. Watch the video from Gear Show:

The Nimh battery cell fully charged voltage is around 1.5V so with 20 cells in series connection, the total voltage is around 1.5V x 20 ~ 30V.

The lithium battery 18650 cell fully charged is 4.2V, so to get voltage around 30V I need connect them in series 7 times. 4.2V x 7 ~ 29.4V. I choose bms 7S60A high load current from battery pack to the motor. After restoring and trying to use it, I am very satisfied with this result.