The long awaited Milwaukee M18 Fuel rechargeable air compressor has been in the works for a while. Carpenters has tested its per-charge claim on 1,600 18-gauge nails. Some users have even tried a Milwaukee battery-operated air compressor with an impact wrench and tire inflation. I am a professional plumber by profession. While it may seem unusual for someone like me to review a 2840-20 compressor, I have a few thoughts. First, I can use it on the job site without electricity. In fact, my team has now successfully used it to vent and air test PEX heaters on multiple pipes.
advantage
- Compact, rugged and convenient design with carrying handle and roll cage
- 68dB quiet operation
- Save time working without power
- 135 PSI, 1.2 SCFM @ 90 PSI Sufficient for many light duty tasks
shortcoming
- At 31.2 pounds, it's a bit heavier than several of its competitors
Check out our Best Air Compressors article to see our top picks for a variety of applications and uses.
Milwaukee M18 Fuel Compact Compressor for Discharge Heater
Even where there is electricity, we usually bleed the heater manually. With the Milwaukee M18 Fuel Compact Quiet Compressor, I can just let it do all the work. The compact design and convenient carrying handle make it an excellent job site compressor. I also like the protective roll cage, which is super easy to store in the van and move around the job site.

I had a co-worker "borrow" a Milwaukee cordless air compressor to stress test a new sewer line. He uses a 2840-20 instead of a hand pump. It works pretty well — in fact, much faster and with less effort than the old-fashioned way. He endorsed it further and made it hard for me to get it back!
Milwaukee Chargeable Air Compressors for Pressure Testing
Our neck-o-the-woods street pressure is 75 PSI. Therefore, we typically pressure test repiping jobs for at least 15 minutes using a 150 PSI compressor. This gives us confidence that the pipeline is ready. Of course, this pressure is far more than what is required for the test, but it provides additional peace of mind. At 135 PSI, the Milwaukee M18 Fuel Compact Quiet Compressor didn't quite pass our maximum pressure test, but it easily meets rough PSI levels. Our electric pancake compressor can go up to 150 PSI, but if the job site has no power, Milwaukee can be used as a very close approximation.

To test the pressure, we use a hose spigot with a gauge to connect the line to a Milwaukee battery operated air compressor. The 2-gallon water tank provides plenty of volume for the task. Then we pump it up and look at the gauges. Usually, we do this at lunchtime so there is plenty of time to sit down. When we get back to the job site, we look at the gauges. If it reads the same pressure, we're in business!

The convenience of wireless and the ability to get work done on jobsites without power comes with some time tradeoffs. The Milwaukee M18 Fuel Cordless Air Compressor takes over 90 seconds to charge. Still, it's much faster than doing nothing!
Woodworking with the Milwaukee 2840-20
While I'm a plumber by trade, I also do a lot of carpentry. I recently converted my kitchen into a "tasty factory" (my wife's term). I use a Milwaukee M18 Fuel Compact Quiet Compressor on some trim jobs. The Milwaukee cordless compressor helps me drive 2" brad nails with ease – the nailer never exceeds the air supply.
The convenience of using a really quiet battery powered compressor cannot be overemphasized. Milwaukee measured far less noise output than noisy pancakes. The sound pressure level we measured with a decibel meter was only 72 dBA. If I were a professional carpenter, I'd want this on every pruning job, whether or not I had power available!

price
You can buy the Milwaukee battery-operated air compressor as a bare-bones unit for $349. Kit options are available for $548 (12.0 High Output Battery) and $598 (12.0 High Output Battery and Charger). Let's take a look at the game.
- Ridgid 18V kit with (2) 2.0 batteries and charger only (1 gallon): $297
- DeWalt FlexVolt 60V Max kit with only 6.0 batteries and charger (2.5 gal) DCC2560T1: $299
- Milwaukee M18 Fuel Compact Silent Compressor (2 Gallon) 2840-20: $349
Milwaukee Battery Powered Air Compressor Bottom Line
The Milwaukee M18 Fuel Compact Quiet Compressor seems to be the cordless tool that Milwaukee fans have been eagerly waiting for. It's quiet and powerful, especially with the 12.0 battery. It also takes up almost no space and is easy to carry. Carpenters will undoubtedly benefit from its functionality, but other professionals like plumbers can also take advantage of it as I do.

Specification
- Model:
- 2840-20 (bare metal)
- 2840-20BAT (with 12.0 high output battery)
- 2840-20KIT (with 12.0 high output battery and charger)
- Sound output: 68dB(A) SPL
- Fuel tank capacity: 2 gallons
- Maximum Pressure: 135 PSI
- SCFM: 1.2 @ 90 PSI
- Pump Type: Oil Free
- Regulator: Singleturn
- Dimensions (L x W x H): 16.25 x 18.62 x 10.6 inches
- Weight: 31.2 lbs.
- price
- 2840-20 (bare metal): $349
- 2840-20BAT (with 12.0 high output battery): $548
- 2840-20KIT (with 12.0 high output battery and charger): $598