Hey there, drone enthusiasts! If you’re diving into the world of custom drone builds or looking to upgrade your current setup, you’ve probably realized that Electronic Speed Controllers (ESCs) are kind of a big deal. These little devices might not get as much attention as flashy motors or cameras, but trust me - they’re the unsung heroes that can make or break your flying experience.
I’m going to walk you through everything you need to know about choosing ESCs for your drone, from the basics to some of the nitty-gritty details that most guides skip over. Like with my LiPo battery guide, I’ll start with a TL;DR for those of you who just want the quick version.
Think of an ESC as a super smart power regulator that sits between your battery and motors. When your flight controller sends a signal like “Motor 3 needs to spin at 75% power right now,” the ESC translates that digital command into the precise electrical current needed to make that motor spin at exactly the right speed.
This might sound simple, but in a drone, these calculations are happening hundreds of times per second, and even tiny delays or inaccuracies can mean the difference between butter-smooth flight and a twitchy mess that’s constantly fighting you.
ESCs aren’t just dumb power switches either - modern drone ESCs are mini-computers that handle:
The ESC is doing all this complex work while being bombarded with vibration, heat, and electromagnetic interference. No wonder they sometimes fail! Let’s make sure you choose ones that won’t.
The amp rating tells you how much continuous current your ESC can handle without turning into a firework display. This is super important to get right.
Here’s how to figure out what you need:
For example, if you’re running motors that pull 28A at full throttle with your chosen props:
28A × 1.2 = 33.6A minimum rating neededYou’d want to go with 35A or 40A ESCs to be safe.
I’ve seen way too many people try to cheap out here and go with the exact rating or less. Don’t be that person! When your ESC fails mid-flight because you pushed it too hard on a hot day, you’ll wish you’d spent the extra $5 for higher-rated ones.
Here’s a real-world example: I was flying a 5” freestyle quad with EMAX ECO II 2207 1700KV motors on a 4S battery with 5.1” props. The motor specs claimed they’d pull around 28A max, but when I hooked everything up to a current meter during a punch-out, they actually pulled spikes of 32-33A! If I’d gone with 30A ESCs, I’d have been in for a bad time.
ESCs are designed for specific battery cell counts, usually shown as an “S” rating:
Using an ESC with a battery that exceeds its voltage rating is asking for a spectacular but short-lived light show. The magic smoke will escape and your ESC will never work again. Been there, done that when I accidentally plugged a 6S battery into a 4S-rated build. Oops.
You’ve got two main options for ESC configuration:
Individual ESCs (one per motor):
4-in-1 ESCs (all four on one board):
For most modern 5” builds, I strongly recommend 4-in-1 ESCs unless you have a specific reason not to use them. The wiring simplicity alone is worth it, and they’ve gotten much more reliable in recent years.
The ESC firmware world has changed quite a bit recently. Here’s what you need to know:
This is still the budget workhorse of the drone world:
If you’re on a tight budget, BLHeli_S ESCs will absolutely get the job done. I still use them on some of my beater quads that I don’t mind crashing.
This is my current go-to recommendation for most builds:
With BLHeli_32 development shut down, Bluejay has become the natural successor for many pilots. It gives you most of the benefits of more expensive ESCs without the higher price tag.
This is the up-and-coming alternative that’s generating a lot of buzz:
Pros:
Cons:
I’ve been testing AM32 ESCs on my freestyle build for about two months now, and I’ve noticed they feel more connected and responsive, especially during quick direction changes. However, I spent a good few hours tuning them to get everything dialed in just right.
The premium option in the ESC world:
KISS ESCs have a dedicated following, and for good reason - they just work, and they work really well. If budget isn’t a major concern and you want a polished experience, they’re worth considering.
The protocol is essentially the language your flight controller uses to tell your ESCs what to do. Newer protocols are digital and more precise:
The current standard comes in several speeds:
DShot was a game-changer because, unlike older protocols, it’s digital. This means it’s not affected by small voltage fluctuations that can cause inconsistencies in analog signals.
This is a feature worth seeking out - it allows the ESC to send data back to the flight controller, specifically motor RPM information. This enables:
In my experience, bidirectional DShot with RPM filtering is one of the biggest improvements you can make to any build. It’s like going from standard definition to HD - suddenly everything is clearer and more precise.
You might still see these mentioned:
Unless you’re working with legacy equipment, stick with DShot.
I’ve built dozens of drones, and here are some hard-earned lessons about ESC installation:
Most ESCs these days come with a capacitor that needs to be soldered to the power input. Don’t skip this! The capacitor helps filter out voltage spikes and noise that can cause issues with video feed and flight performance.
For a 4-in-1 ESC, you’ll want to solder the capacitor as close to the power input as possible. I like to add a bit of heat shrink tubing over the leads to prevent any shorts.
Vibration is the enemy of good flight performance. Consider these options:
On my freestyle quad, I use 3M VHB tape to mount the 4-in-1 ESC to the frame, and the difference in gyro noise compared to hard mounting is significant.
If you ever fly near water, snow, or in humid conditions, consider adding conformal coating to your ESCs. This clear protective layer helps prevent shorts from moisture. Just be careful to mask off any connectors or components that shouldn’t be coated!
The days of beeping and booping through ESC programming with your transmitter are (thankfully) behind us. Here’s what you’ll need:
For BLHeli_S and Bluejay firmware:
I still use this for most of my builds since it’s simple and gets the job done with minimal fuss.
If you go the AM32 route:
When using AM32, be prepared to spend some time learning what all the settings do. The payoff can be worth it, but it’s definitely not “plug and play” like BLHeli.
For KISS ESCs:
In a typical quadcopter, motors need to spin in specific directions to counteract each other’s torque:
Getting this wrong is a common beginner mistake that results in a drone that flips over immediately on takeoff. Been there, done that, got the broken props to prove it!
This affects how the ESC drives the motor:
I typically use medium timing (around 22°) for freestyle flying as it gives a good balance of responsiveness and efficiency.
Modern ESCs with digital protocols usually don’t need manual throttle calibration, but it’s still good practice to check that your ESCs are responding through the full throttle range in your flight controller’s motor test tab.
A desync happens when the ESC loses track of the motor’s position, resulting in a momentary loss of power or stuttering. This often happens during rapid throttle changes or if there’s a mismatch between ESC timing and motor requirements.
If you’re experiencing desyncs:
I once had persistent desyncs that drove me crazy until I realized one motor had a slightly bent shaft from a crash. Replaced the motor, problem solved!
If your ESCs are getting too hot to touch after flights:
On a hot summer day in Phoenix, I had to add a tiny 20mm fan to my 4-in-1 ESC to prevent overheating during long freestyle sessions. Made a world of difference!
Most ESCs use beep patterns to communicate issues:
Learn to listen to what your quad is telling you through these beeps!
As we move forward in 2025, a few trends are becoming clear:
Keep an eye on these developments, but don’t worry too much about having the absolute latest tech. A solid, reliable setup that you understand well will always beat bleeding-edge components that you’re struggling to configure properly.
After all this information, here’s my practical advice for different types of builds in 2025:
Remember, the “best” ESC is the one that matches your specific needs, flying style, and the rest of your components. Don’t get too caught up in having the latest and greatest—reliability should always be your top priority.
Happy building, and may your ESCs never let out the magic smoke!
Published Apr 09, 2025