Black & Decker - Dust Buster: battery replacement

I've charged 4x2000mAh cheap cells externally and just put them into the B&D vacuum for runtime testing.

I've used the vacuum for around 20-25 times for cleaning the cat litter and hair around the apartment.

-> 1 week without charging

I think this is enough, because I don't want to have the charger always on.

Next steps:

• Waiting for the BMS module for balanced charging
• Writing the HD instructions :-)

For testing purposes, I've tried the vacuum without a battery protection circuit.

The performance was good, but not the best. The battery capacity seems to be enough for ~10-15min, but the cheap "9900mAh" batteries are getting warm after ~30s.

The next try will be with 2x2 batteries (1+1||1+1), so this is the added 2nd battery holder:

I will measure the runtime with 4x2Ah cheap cells and 4x3Ah good cells.

Yesterday I've disassembled the vacuum cleaner and tried to connect the new battery pack.

My first try was a combination of 2 18650 cells in a cheap battery holder with a 10A battery protection board ( https://www.aliexpress.com/item/32920842556.html ).

It was not possible to start the motor, the short circuit protection immediately kicks in and cuts of the power.

Next try:

20A board. There are 30A boards as well, but only for 3S, which would be too much for the motor (original voltage: 9.6V; 2S: 7.2V; 3S: 10.8V).

https://www.aliexpress.com/item/32863604994.html

with a balancing circuit (~2$).