Best Product – Reader Question: Why Does my Milwaukee M18 Cordless Vacuum Sound Different?

Milwaukee Tool M18 0880-20 Cordless Wet-Dry Vacuum

A reader wrote in with a great question, asking why his Milwaukee M18 cordless wet/dry vacuum sounds different depending on the battery being used to power it.

Jp wrote:


Hello, I purchased a M18 small wet/dry shop vac (not the backpack). I noticed this weekend a higher rev sound with 12.0 batteries than with 9.0 batteries. Does this indicate that the vac is like a “Fuel” product which acts differently with high-output batteries? There is no fuel branding on the vac. Would they silently upgrade a product to “Fuel” tech without the overt branding?

I’m assuming that Jp is referring to Milwaukee’s 0880-20 vacuum, shown above, a compact M18 wet/dry vac that’s been around for a while.

This is a brushed motor vacuum, and although it has been updated over the years, but not the motor. This is still a brushed motor vacuum.

Michael Q. wrote in, back in 2017, after discovering the updated design:

Milwaukee Tool M18 0880-20 Cordless Wet-Dry Vacuum 2017 Update

Michael – I’m sorry for not being able to get back to your email in a timely manner, but you were exactly right about the major differences – the 0880 was updated with a larger battery compartment to fit newer M18 batteries, and the internal storage compartment was reworked to allow for internal hose storage. There are a couple of smaller changes as well.

I followed up about the 0880 well after Michael’s original email, triggered by another email or two about the changes.

Previous 0880-20 New 0880-20
96 dB 92 dB
Compatible with NiCd and M18 Compatible with M18 only
Accessory storage outside unit Accessory storage enclosed & inside unit
Standard on/off switch Waterproof on/off switch
Flip up handle Integrated handle
Flat hose end Angled hose end for quicker cleanup
Flat surface area utility nozzle Improved & larger surface area utility nozzle
Washable filtration No washable filtration

“New” refers to changes made in October 2017, and presumably no further changes or updates have been made since then.

Okay, so what’s going on with Jp’s Milwaukee M18 cordless vacuum? Why does it have a different sound profile depending on the type of battery pack used to power it?

Usually, the noise a motor makes could indicate a difference in speed or power as it changes, with even subtle shifts being noticeable.

I reached out to Milwaukee, and this is what they said:

When brushed motor products are equipped with a higher output battery pack, it could cause a little more noise because the additional power and less impedance of the high output pack causes the motor to spin slightly faster. This is often more noticeable on products that move air, like fans. On our [brushless motor] FUEL products we are able to control the motor a bit more because of the advanced electronics.

Sounds like a reasonable explanation to me.

Thank you to Jp for a great question, and also Michael Q. for writing in about the 0880 update so long ago.

Mysteries solved!!

I have one of these cordless vacuums, purchased two holiday shopping seasons ago when I spotted a great deal, and it has held up wonderfully in the years since. I’d buy it again in a heartbeat.

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