You're standing on a job site, or maybe you're just stuck in your driveway during a power outage, and you look at your stack of red batteries. If you've bought into the Milwaukee ecosystem, you probably have a dozen M18 packs rolling around your truck bed. It makes sense to want a Milwaukee portable power station that just works with what you already own. But here is the thing: the Milwaukee M18 CARRY-ON 3600W/1800W Power Supply isn't exactly a "power station" in the way a Jackery or an EcoFlow is.
It's a different animal entirely.
Most people buy these things thinking they can run a fridge for three days during a hurricane. You might be disappointed if that's your plan. Honestly, Milwaukee built this for the guy who needs to run a table saw where there isn't a plug, or the crew that needs to charge phones and laptops in a gang box without tripping a breaker. It’s a tool. It isn't a camping accessory, though you could certainly use it for that if you don't mind the weight.
What the M18 Carry-On Actually Does
The Milwaukee M18 Carry-On Power Supply (2845-20) is basically a sophisticated inverter. It takes four M18 batteries and pushes out 3600 starting watts and 1800 running watts of pure sine wave power. That "pure sine wave" part is actually a big deal. Cheaper inverters use modified sine waves which can basically fry your laptop or make your microwave hum like it’s about to explode. Milwaukee used the good stuff here so your sensitive electronics stay safe.
But there is a catch. It requires all four battery bays to be populated to hit that peak 3600W output. You can’t just slap one 5.0Ah battery in there and expect to run a circular saw. It doesn’t work like that. The system pulls from all four batteries simultaneously to distribute the load, which keeps the batteries from overheating and extends their lifespan. If you’ve ever felt how hot an M18 battery gets after heavy drilling, you’ll understand why this matters.
The design is rugged. It’s got a roll cage. It looks like it could fall off a tailgate and keep ticking, which is more than I can say for those sleek, plastic power stations you see on Instagram.
The Battery Math Most People Ignore
Let’s talk real numbers because marketing jargon is usually garbage. If you put four 12.0Ah High Output batteries into this Milwaukee portable power station, you have a total capacity of about 864 watt-hours.
Think about that for a second.
A standard "large" dedicated power station often starts at 1000Wh or 2000Wh. If you’re running a 15-amp corded tool, you are going to chew through those batteries fast. We are talking maybe 20 to 30 minutes of continuous, heavy cutting. For a carpenter making intermittent cuts throughout the day? It’s a godsend. For someone trying to run a space heater in a tent? Forget about it. You’ll be in the dark by midnight.
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This is the fundamental trade-off of the Milwaukee system. You aren't buying capacity; you're buying convenience and discharge rate. It can dump power fast enough to start a high-draw motor. Most "lifestyle" power stations struggle with that initial surge and will just throw an error code. Milwaukee’s M18 CARRY-ON just grunts and gets to work.
Real World Use: Not Just for Saws
I’ve seen guys use these for some pretty creative setups. One electrician I know uses it specifically for "temp power" during panel swaps. He can keep the homeowner's internet and a few lights running while the main power is killed. It makes him look like a hero.
- It has two 120V outlets.
- One USB-C PD port (which is great for fast-charging a MacBook).
- One USB-A port.
- An onboard charger.
Wait, the charger part is huge. When you finally get back to a wall outlet, you plug the unit in, and it charges all four batteries inside it. It’s a 4-bay sequential charger. It isn't the fastest charger Milwaukee makes—don't expect Supercharger speeds—but it simplifies your life. One cord, four batteries, no mess.
Why It Beats a Gas Generator (Sometimes)
Gas generators are loud. They smell. They require you to carry a gas can that eventually leaks in your trunk. The Milwaukee portable power station is silent. Truly silent. You can run it in a basement, a crawlspace, or a bedroom without worrying about carbon monoxide poisoning.
There's also the "instant on" factor. No pulling a cord eighteen times in the cold. You hit a button. You have power. For service technicians working in finished homes, this is the professional way to work. Bringing a gas-chugging Honda EU2200i onto a customer's manicured lawn is a vibe, but maybe not the one you want.
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The Competition: MX FUEL vs. M18
If you really need to run the heavy stuff, Milwaukee has the MX FUEL Carry-On. That’s the big brother. It’s also significantly more expensive and uses a completely different battery platform. If you aren't already on the MX FUEL line, the M18 version is much more practical.
However, we should be honest about the price. The M18 Carry-On is not cheap. When you add the cost of four 12.0Ah batteries, you’re looking at a serious investment. If you already own the batteries, the "tool-only" price is manageable. If you don't? You might be better off looking at a dedicated unit like a Delta 2 or a portable solar generator.
Common Frustrations and Weird Quirks
It isn't perfect. One thing that bugs people is the lack of a detailed LCD screen. You get some basic LED bars to show battery life, but it doesn't tell you exactly how many watts you’re pulling or exactly how many minutes of runtime you have left. In 2026, that feels a bit dated. Most modern power stations have apps and Bluetooth monitoring. Milwaukee kept it "job site simple," which some call durable and others call lazy.
Also, it's heavy. With four 12.0Ah batteries inserted, you're lugging around a significant chunk of weight. The handle is sturdy, but you won't want to carry it a mile into the woods.
Is It Right For You?
You have to look at your tool chest. Do you have a sea of red? If yes, this is a no-brainer for emergency backup and remote work. If you have DeWalt or Makita tools, buying into this just for the power station is a mistake. You'd be paying a premium for a battery interface you can't use elsewhere.
The Milwaukee portable power station shines in the "intermittent high-draw" category. It’s for the guy who needs to drill ten holes in concrete where there’s no power, or the photographer who needs to charge camera batteries and a laptop in the middle of a field.
Actionable Next Steps
Before you drop the cash, do a quick audit of your power needs. Check the labels on your devices. A standard laptop uses about 60W. A small fridge might pull 100W but spikes to 600W when the compressor kicks in.
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- Calculate your "Big Four": Identify the four 12.0Ah or 8.0Ah batteries in your collection. If you only have 5.0Ah packs, the runtime on this unit will be disappointingly short for high-draw tools.
- Check the Sine Wave: If you're comparing this to a cheap off-brand inverter, remember that the Milwaukee provides "Pure Sine Wave" power. Don't risk your $2,000 MacBook on a $100 modified sine wave inverter.
- Plan Your Charging: Remember that this unit charges batteries sequentially, not all at once. If you need all four batteries topped off in an hour, you'll still need your external Rapid Chargers.
- Evaluate Your Mobility: If you need wheels, look at a cart or a Packout mod. This unit is not natively Packout compatible, which is a weird oversight by Milwaukee, but plenty of people have come up with clever DIY mounting solutions.
Ultimately, this isn't a "set it and forget it" home backup system. It’s a mobile power solution for people who treat their gear like it's meant to be used. It’s tough, it’s reliable, and it uses the batteries you already trust. Just don't expect it to run your whole house, and you'll be more than happy with it.