Black & Decker - Dust Buster: battery replacement

Description

Recently I got a hand vacuum cleaner for free. Why? Of course: the battery pack is dead.

I don't want to throw it away, so I'm going to replace the internal battery pack with replaceable 18650 LiIon cells.

The modification consists of:
* removing old battery
* replacing the the cells with 2x 18650 cells and a balancer circuit
* replacing the original charger with a USB step-up 2S charger

Components

1 × B&D Dustbuster Extreme Connectors and Accessories / Euro Connectors

2 × 2S battery holder e.g.: https://www.aliexpress.com/item/32847696147.html

1 × 2S BMS - 20A - balanced version e.g.: https://www.aliexpress.com/item/32863604994.html

2 × 18650 cell I used some cheap cells I got with a head-lamp

1 × USB 2S boost charger e.g.: https://www.aliexpress.com/item/32949889484.html

Project Logs

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4x2000mAh: vacuum runtime

benjaminaigner • 10/06/2019 at 07:52 • 0 comments

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 :-)

Test without battery protection board

benjaminaigner • 09/29/2019 at 14:49 • 0 comments

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.

First try - battery pack test

benjaminaigner • 09/24/2019 at 17:55 • 0 comments

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$).

Build Instructions

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1

Disassemble DustBuster

Remove the 7 screws.

Note: the screw near the charging port is different.

Remove the knob on the other side (the screw is under the cap)

Pull out the battery pack + fan + motor

Split motor and battery pack.

Note: take care of the clips.

Remove the LED module completely. Attention: the metal stripes are not attached well, take care when pulling off the cables.
2

Disassemble battery pack

Open the pack by pressing the 4 clips and pulling it apart

Cut off both wires to the battery pack, dispose the cells appropriately.

Keep the charging port :-)

Remove the plastic cell separators in the case
3
Adapt 18650 holders, assemble battery with BMS
A small note for this step:

I've tried around a few variants, so the wiring I show here is messy.

If you want to repeat this step, maybe you think of a way to do it much better. But I'm using the DustBuster for 6 weeks in this configuration and I'm satisfied:-).
- Cut off the original thin wires from the battery holders
- Attention. Don't mess up the polarity!!!
- Note: the battery pack is not very "solder friendly". Heat up only a short time, and use an air filter!
Step by step connections:
- Connect the charger port + to the BMS load +
- Connect the charger port - to the BMS load -
- Connect +/- from both battery holders
- Connect +/- from the battery holders to the battery +/- from the BMS
- Connect the motor +/- (upper and lower connector) to the BMS battery +/-. //I had the problem, that the BMS was triggered all the time by the inrush current of the motor. Although the continuous current was way below battery/BMS specs (around 8A).
Connect the balancing connection on the other side:
- Both battery packs
- "4.2V" label of the BMS
Inserting the batteries: You need 4 equally charged cells from the same type & age.

And now: try to fiddle everything into the case...

I've used double sided adhesive foam tape to keep the BMS isolated.

Put both sides of the battery case back together.

Please take care of the batteries: do not damage the cells in any way!

Double watch of any possible short circuits!

View all 5 instructions

Discussions

Dan Maloney wrote 09/23/2019 at 15:07

I always found those Dust Buster vacs to be surprisingly useful. Trouble is they sit and charge for so long between uses that the battery packs just cook. Glad to see you putting one to use rather than landfilling it.

Are you sure? yes | no

benjaminaigner wrote 09/24/2019 at 09:32

Yeah, you're right. AFAIK there is none of these devices which were thrown away because of another reason than a dead battery...

I tried it yesterday with the given parts, but the 10A short-circuit protection immediately triggers, so I'm waiting for the 20A board (originally for power-drills) :-)

My plan is to include a battery meter, and I think I will charge it only if the battery is below a certain level. Let's see if this is practical ^^

Are you sure? yes | no

Black & Decker - Dust Buster: battery replacement

Description

Components