Have you attempted this? Found this forum through google, I have same hoover here. What bosch does with this is absolutely criminal. The hoover in question works 5-10 minutes from full charge. I thought one of the cells died hence low run time, I've disassembled it and taken out ALL Samsung cells out and then tested each one of them separately and ALL of them have 90% factory capacity and ALL of them are within 30mah from each other, yet Bosch must have set up controller to only run at ~15% factory run time! at this capacity/charge cycles!It just this minute struck me that there are only two wire connecting to the motor. Looking closely, I can see that the coils are in the rotor. Thus a brushed DC motor.
Therefore I can simply remove the entire Bosch circuit board and replace it with a 7S BMS and and a solid state relay or similar to bypass all the Bosch planned obsolescence crap.
Cheaper, simpler and more certain than trying to restore the eeprom(s) to factory defaults.
To add to insult, if you disconnect/connect the battery pack in incorrect order the atmega chip will get in blocked mode and the board is bricked.
I've purchased 7s BMS and a charge indicator, just wondering what relay to use or whether I can somehow reuse some of the components on the original board for switching ground(motor works of switched ground). It also runs at 10A(brush motor at around 1A), I was thinking to get the motor to run at full power with switch in position 1 and in 2-3 to run motor and the brush motor together. Not fussed about running it at lower voltages.
Attached is the eeprom dump for this hoover too(from a working one), in case someone decides to go that way.