Choosing the right motor is one of the most important decisions when building a 4 inch FPV drone.
Compared with larger 5 inch freestyle builds, 4 inch quads require a careful balance between weight, thrust, efficiency, and responsiveness. A motor that is too small may feel underpowered, while an oversized motor can reduce efficiency and make the build heavier.
The MEPS SZ1804 motor was designed for lightweight FPV builds that need strong acceleration and precise control. In this review, we tested the MEPS SZ1804 3500KV motor on an Apex 4 inch quad to see how it performs in a real freestyle setup.
Why Choose 1804 Motors for a 4 Inch FPV Drone?
When selecting motors for a 4 inch FPV drone, pilots usually choose between several motor sizes, including 1505, 1804, and 2004.
The motor size directly affects flight characteristics.
| Motor Size | Characteristics | Suitable For |
|---|---|---|
| 1505 | Lightweight and efficient | Lightweight cruising builds |
| 1804 | Balanced thrust, weight, and control | 4 inch freestyle drones |
| 2004 | Higher torque and power | Aggressive freestyle builds |
For many 4 inch freestyle builds, 1804 motors offer an excellent middle ground.
They provide:
- Faster throttle response compared with smaller motors
- Better recovery after dives and flips
- Enough efficiency for longer flight times
- Lightweight performance for compact frames
This makes 1804 motors a popular choice for pilots who want a small quad that still feels powerful. Here is a detailed guide of FPV motor size guide.
MEPS SZ1804 Motor Specifications
The MEPS SZ1804 is a lightweight FPV brushless motor available in different KV options for different battery setups. The 3500KV version is designed for 4S builds, while the 2450KV version is suitable for 6S applications.
| Specification | MEPS SZ1804 |
|---|---|
| Motor Size | 1804 |
| KV Options | 3500KV / 2450KV |
| Recommended Battery | 4S / 6S |
| Shaft Diameter | 1.5mm |
| Magnet | N52H Arc Magnet |
| Material | 6061 Aluminum Alloy |
| Maximum Thrust | Up to 731g |
| Application | 3-4 inch FPV builds |
The motor uses a Uni-Bell design that improves durability while keeping the overall weight low. The reinforced structure helps protect the motor during crashes, which is especially important for freestyle pilots.
MEPS SZ1804 3500KV Unboxing and First Impressions
Once we’re cozily back indoors, it’s time to unwrap our treasures. True to my hunch, inside the package are the motors I’ve been eagerly anticipating. The packaging itself is impressive, signaling the quality of the contents. As I unbox one of the motors, the first thing that strikes me is its aesthetic appeal and the attention to detail in its construction.
What’s Included:
- A well-crafted SZ 1804 3500 KV Motor
- Cool space-themed MEPS Stickers
- A quality control card from MEPS, ensuring the motor meets their high product standards and technical requirements
- Accessories including a washer, a spare C clip, and two different sizes of screws for mounting
First Impressions
The 1804 3500 KV motors are not just about looks; they feel robust, with strong magnets and thoughtful design touches like epoxy or silicone at the wire ends to prevent damage during crashes or rough handling. This level of detail promises durability and reliability, essential for any serious FPV quad build.
Building an Apex 4 Inch FPV Quad With MEPS SZ1804 Motors
For this test, the MEPS SZ1804 3500KV motors were installed on an Apex 4 inch frame.
The previous setup used 1505 motors at 3750KV, which already provided good performance. The goal of this upgrade was to compare whether the larger 1804 stator size could deliver better power and flight control.
Build setup:
| Component | Setup |
|---|---|
| Frame | Apex 4 inch |
| Motor | MEPS SZ1804 3500KV |
| Battery | 4S LiPo |
| Camera | Caddx Ratel |
| Video System | TBS UniFi Pro 32 |
After installation, the motors matched the lightweight Apex frame well, providing a good balance between compact size and performance.
Flight Performance: How Does the SZ1804 Perform?
During the maiden flight, the MEPS SZ1804 3500KV motors showed strong throttle response and smooth control. The biggest improvement compared with smaller motors was the feeling of power reserve.
Instead of requiring higher throttle input during aggressive maneuvers, the SZ1804 motors provided stronger acceleration and more confidence when recovering from fast movements.
For freestyle flying, the advantages were noticeable:
- Strong Throttle Response: The increased stator size provides more torque, allowing the quad to accelerate quickly.
- Smooth Control: The motor response feels predictable, making precise movements easier.
- Better Freestyle Capability: Loops, rolls, and fast direction changes benefit from the additional power.
MEPS SZ1804 vs 1505 Motors: What Changed?
One of the biggest questions for 4 inch pilots is: Are 1804 motors better than 1505 motors? The answer depends on the flying style.
| / | 1505 3750KV | MEPS SZ1804 3500KV |
|---|---|---|
| Weight | Lower | Slightly higher |
| Thrust | Good | Higher |
| Acceleration | Fast | Stronger |
| Flight Feel | Light and agile | More controlled |
| Freestyle Performance | Good | Better |
The 1505 setup feels extremely lightweight and responsive. However, the SZ1804 provides additional torque, making the quad feel more stable during:
- Punch outs
- Fast direction changes
- Recovering from dives
- High-speed freestyle moves
For pilots who want a 4 inch quad that feels closer to a 5 inch freestyle drone, the extra motor size can be beneficial.
Who Should Choose MEPS SZ1804 Motors?
The MEPS SZ1804 is a good choice for pilots who build:
4 Inch Freestyle FPV Drones
The motor size provides the power needed for aggressive freestyle flying while keeping the quad compact.
Lightweight Apex-Style Builds
For lightweight frames, 1804 motors create a strong power-to-weight ratio.
Pilots Upgrading From 1505 Motors
If your current 4 inch quad feels underpowered, moving to an 1804 motor can improve acceleration and overall flight confidence.
Recommended Battery Setup for SZ1804 Motors
Choosing the correct KV version is important.
MEPS SZ1804 3500KV
Recommended:
- 4S LiPo battery
- 4 inch freestyle builds
- Lightweight setups
MEPS SZ1804 2450KV
Recommended:
- 6S LiPo battery
- Higher efficiency builds
- Longer flight applications
Using the correct KV and battery combination helps maintain motor efficiency and avoid unnecessary heat buildup.
Closing Thoughts: A Successful Build with MEPS Motors
The MEPS 1804 motors have proven to be an excellent choice for the Apex 4″ frame, offering the perfect blend of power, efficiency, and durability. This build is a testament to the quality of MEPS motors and their capability to enhance the FPV flying experience.
Thank you for joining me on this build and flight adventure. Despite the cold, the thrill of flying keeps us warm. Stay tuned for more episodes, and consider grabbing some MEPS motors for your next build. Until next time, take care and happy flying!
FAQ
Is 1804 motor good for a 4 inch FPV drone?
Yes. 1804 motors provide a strong balance between weight and power, making them suitable for many 4 inch freestyle builds.
What KV motor should I use for a 4 inch FPV drone?
For most 4S 4 inch freestyle builds, around 3500KV is a common choice. For 6S builds, a lower KV option such as 2450KV is more suitable.
Are 1804 motors better than 1505 motors?
1804 motors generally provide more torque and thrust, while 1505 motors are lighter and more efficient. The better choice depends on whether you prioritize freestyle power or lightweight efficiency.