You’re standing on a roof or maybe just in your driveway, and you need to rip a sheet of plywood. In the old days—basically ten years ago—you’d be hunting for an extension cord. You’d trip over it. It would snag on a sawhorse. It was a whole thing. Then the DeWalt 20V battery circular saw showed up and basically told the corded world to take a hike.
It’s weird how attached we get to yellow tools. Honestly, it’s partially the branding, but mostly it's because these things just don't die. If you’ve ever used the DCS391, you know exactly what I’m talking about. It’s light. It’s balanced. It feels like an extension of your arm rather than a bulky machine you’re fighting against. But let's be real: not every 20V saw in their lineup is a home run. There are nuances here that most "top ten" review sites completely ignore because they haven't actually spent eight hours a day cutting 2x4s until their wrists ache.
The power gap: Brushed vs. Brushless
Most people walk into a big-box store, see the $99 special, and think they’re getting a steal. They aren't. That entry-level DeWalt 20V battery circular saw usually has a brushed motor. It sparks a bit. It smells like ozone when you push it through wet pressure-treated lumber. It works fine for hanging a shelf, but if you’re framing a deck? You’ll hate it.
Brushless is the only way to go now. Why? Because the motor communicates with the battery. It’s smarter. When the saw hits a knot in the wood, the brushless controller dumps more current into the motor to keep the RPMs up. A brushed saw just bogs down and cries. The DCS570 is the workhorse here. It’s a 7-1/4 inch saw, which matters because you can actually find blades for it at a gas station in the middle of nowhere if you have to.
Short saws suck for deep cuts. The 6-1/2 inch models are cute and lightweight, and yeah, they’re great for trim. But try cutting a 4x4 post with one. You can't do it in one pass. It’s frustrating. You end up with these jagged edges that you have to clean up with a sander or a prayer.
Real talk about battery life and the "20V Max" branding
Let’s clear something up. DeWalt calls it "20V Max." In the rest of the world, like Europe, they call it 18V. Why? Because 20V is the maximum initial battery voltage measured without a workload. The nominal voltage is 18V. It’s marketing. Is it dishonest? Sorta. Does it matter? Not really, as long as the saw cuts.
If you’re running a DeWalt 20V battery circular saw on a 2.0Ah battery, you’re doing it wrong. You’ll get maybe ten or fifteen good cuts before the power sags. It’s like trying to run a marathon while breathing through a straw. You need the 5.0Ah packs at a minimum. Better yet, the PowerStack batteries. They use stacked pouch cells instead of cylindrical ones. They’re smaller, they stay cooler, and they provide way more "punch." If you’ve ever felt a saw "stutter" in a long rip cut, it’s usually the battery overheating, not the saw failing.
High-demand tools need high-discharge batteries.
I’ve seen guys try to use the tiny batteries that came with their drill/driver kit on a circular saw. It’s painful to watch. The saw sounds sad. It sounds like it’s giving up on life. Throw a 6.0Ah FlexVolt battery on that 20V saw, even though it’s "just" a 20V tool, and you’ll feel a massive difference. The saw doesn't just run longer; it runs harder.
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Why the blade-left vs. blade-right debate actually matters
This is where the religious wars start in the carpentry world. Most corded saws are blade-right. If you’re right-handed, the motor is between you and the cut. You have to lean over the saw to see your line. It’s awkward.
A lot of the cordless models, especially the smaller DeWalt 20V battery circular saw units like the DCS391, are blade-left. For a righty, this is a godsend. You have a direct line of sight to the blade. You can see exactly where the teeth are hitting the wood without performing gymnastics. But there’s a catch. Since the heavy part of the baseplate is on the waste side of the cut, the saw can tilt as you finish the pass. You have to be careful. You have to practice.
The DCS570 and DCS575 (the 60V big brother) usually stick to the traditional blade-right orientation. Professionals often prefer this because the base sits on the "keeper" piece of wood, making the cut more stable.
It’s about what you’re used to. Honestly, if you’re a DIYer, go blade-left. The visibility will save you from a lot of crooked cuts. If you’re an old-school framer, you’ll probably hate it and call it a "sidewinder" for people who don't know what they're doing. Ignore them. Use what makes your cuts straight.
The ergonomics of the handle and the dreaded safety switch
DeWalt gets the grip right. Most of the time. The overmold rubber is sticky enough that it won't slide out of your hand if you're sweating in 90-degree humidity, but it doesn't feel like it's melting.
However, the safety switch can be a pain. You have to thumb this little lever down before you can pull the trigger. On some models, it’s positioned perfectly. On others, it feels like it was designed by someone who has never actually worn work gloves. You end up fumbling with it for two seconds before every cut. It sounds minor, but do that 200 times a day and you'll want to throw the tool into a pond.
The dust blower is another "invisible" feature. A good DeWalt 20V battery circular saw blows a stream of air right in front of the blade. This clears the sawdust so you can actually see your pencil line. If the blower is weak, you end up blowing on the wood yourself like you're trying to put out a birthday candle. It’s annoying. The DCS570 has a decent blower, though it’s not perfect.
Surprising durability and the "drop test"
I once saw a DCS391 fall off a six-foot scaffold onto concrete. The baseplate (the shoe) was made of magnesium. It didn't bend. It didn't crack. It just got a little scratch. If that had been a cheap stamped-steel shoe, the saw would have been garbage instantly.
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That’s what you’re paying for.
You’re paying for the fact that the guards don't bind. Have you ever used a cheap saw where the lower guard gets stuck on the wood as you start a cut? You have to reach down with your finger to pull the guard back—which is incredibly dangerous—just to get the cut started. DeWalt’s guard geometry is generally excellent. It retracts smoothly, even on thin bevel cuts.
Speaking of bevels, most of these saws go up to 57 degrees. Most people only need 45 or maybe 22.5. But having that extra range for weird roof pitches is a lifesaver. The markings are etched, not just painted on, so they don't rub off after three months of sliding around in a truck bed.
Common misconceptions about "Power Detect" and "FlexVolt Advantage"
DeWalt has been confusing everyone lately with these labels. You’ll see a DeWalt 20V battery circular saw that says "Power Detect" or "FlexVolt Advantage."
Here is the simple version:
- Power Detect: The saw has extra sensors to identify when you’ve plugged in a high-capacity 20V battery (like an 8.0Ah). It then pulls more juice to give you more torque.
- FlexVolt Advantage: The saw can "talk" to a 60V FlexVolt battery. Even though the saw is still 20V, it uses the extra headroom of the big battery to increase its power output significantly—sometimes by 40% or more.
If you already own FlexVolt batteries for your miter saw or table saw, getting the "Advantage" version of the 20V circular saw is a no-brainer. It’s basically a 60V saw in a 20V body. It’s a beast. If you only have the standard 20V batteries, don’t bother paying the premium for those labels. You won't see the benefit.
Real-world maintenance: Don't ignore the basics
These saws are "brushless," but they aren't magic.
Sawdust is the enemy. It gets into the vents. It gets into the trigger mechanism. Every once in a while, take a compressor and blow the thing out. You’d be surprised how much gunk builds up inside the housing.
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And for the love of everything, change your blade. People complain that their DeWalt 20V battery circular saw is "losing power" or "burning the wood." It’s almost never the saw. It’s the dull, $5 blade they’ve been using for three years. A cordless saw lives and dies by the sharpness of its blade. A dull blade creates friction. Friction creates heat. Heat kills batteries and motors.
Buy a decent Diablo blade or DeWalt’s own Precision+ line. The thinner the kerf (the width of the cut), the less wood the saw has to remove, and the longer your battery will last. It’s simple physics.
Actionable Steps for Your Next Project
If you're ready to pick up a DeWalt 20V battery circular saw, don't just grab the first yellow box you see.
First, check your existing battery stash. If you have mostly 2.0Ah or 4.0Ah batteries, plan on buying a kit that includes at least one 5.0Ah or 6.0Ah pack. You will need it.
Second, decide if you're a "blade-left" or "blade-right" person. Go to a store and physically hold both. See which one lets you see your cut line better without twisting your neck. The DCS391 is your go-to for blade-left; the DCS570 is the king of blade-right in the 20V ecosystem.
Third, immediately ditch the "stock" blade that comes in the box. They’re usually okay for rough framing, but if you want clean finishes or better battery runtime, swap it out for a high-quality ultra-thin kerf blade.
Finally, register the tool. DeWalt’s three-year limited warranty is actually decent, but they are sticklers for paperwork. Keep a digital copy of your receipt. If the electronics fry in year two, you'll be glad you did.
Stick to the brushless models, use high-capacity batteries, and keep the vents clear. That saw will likely outlast your next three trucks.
Next Steps for Long-Term Tool Health:
- Clean the Shoe: Occasionally wax the bottom of the aluminum or magnesium shoe with paste wax. It makes the saw glide over the wood with zero effort.
- Battery Storage: Don't leave your 20V batteries in a freezing garage or a boiling hot truck during the summer. Extreme temperatures kill the lithium-ion chemistry faster than heavy use ever will.
- Listen to the Motor: Learn the sound of a "happy" saw. If the pitch drops significantly, back off the pressure. Let the blade do the work. If you force it, you're just wasting battery and wearing out the bearings.