How to choose the right ESC for an RC aircraft
ESC selection by maximum current, voltage, BEC, safety margin, cooling, connector choice and the real load from motor and propeller.
Firma 85A Brushless Smart ESC / 4000Kv Sensorless Motor Combo
Prices are intentionally not displayed on the site.
Contact RC-MODEL for current availability, technical fit, compatible accessories and a formal quote.
Firma 85A Brushless Smart ESC / 4000Kv Sensorless Motor Combo is a Spektrum product intended for surface RC vehicles, crawlers, bashers and race setups that need dependable Spektrum control electronics. This page presents the practical buying information a customer needs before ordering: fit, SKU, image, category, specifications and usage advantages.
The content is written for purchasing through RC-MODEL, without supplier prices or links to competing stores.
Key Advantages
- Organized under the Spektrum telemetry and sensor range.
- Intended for surface RC vehicles, crawlers, bashers and race setups that need dependable Spektrum control electronics.
- Check compatibility with Spektrum Smart equipment and the exact model requirements before ordering.
- Includes local product imagery and structured specifications for easier comparison inside RC-MODEL.
- Spektrum Smart compatibility is highlighted where relevant for batteries, chargers, ESCs or telemetry-aware systems.
- Smart all-in-one telemetry
- Fast, powerful 32-bit ARM M4 processor
- Waterproof
Core Specifications
- Manufacturer: Spektrum
- Brand: Spektrum
- Product Code: SPMXSEMC02
- Product Family: Spektrum telemetry and sensor range
- Application: Surface
- Compatibility Focus: Check compatibility with Spektrum Smart equipment and the exact model requirements before ordering.
- Spektrum Category: Cars & Trucks / Parts, Electronics & Accessories / Electronic Speed Controls
- Input Voltage: 2S LiPo for included motor (do not exceed 2S LiPo power with this motor)
- Amperage: 80A - 99A
- Motor Type: Brushless
- Adjustable Timing: No
- Auto Cutoff: Yes
- Battery Input Lead: IC3
- Battery Type: LiPo (3.7V per cell)
Relevant RC Academy guides
Learn before you buy
These guides explain the setup, safety checks and accessory choices that usually matter for this product type.
How to build a correct electric power system
How to match motor, ESC, LiPo battery and propeller as one complete RC aircraft power setup instead of choosing parts separately.
How to measure current draw with a Watt Meter
A step-by-step safety guide for measuring amps, watts and voltage sag so customers avoid overheating motors, ESCs and LiPo batteries.
Internal BEC vs external UBEC: which should you use?
A guide to receiver and servo power: internal ESC BEC, external UBEC, receiver battery, redundancy and large aircraft safety decisions.
How to choose a LiPo battery for an RC aircraft
Cell count, capacity, C rating, connectors, battery weight and realistic flight time explained for RC aircraft buyers.
| Technical Specifications | |
| Manufacturer | Spektrum |
| Brand | Spektrum |
| Product Code | SPMXSEMC02 |
| Spektrum Category | Cars & Trucks / Parts, Electronics & Accessories / Electronic Speed Controls |
| Connector Type | IC3 |
| Product Family | Spektrum telemetry and sensor range |
| Application | Surface |
| Compatibility Focus | Check compatibility with Spektrum Smart equipment and the exact model requirements before ordering. |
| Battery Type | LiPo (3.7V per cell) |
| Adjustable Timing | No |
| Auto Cutoff | Yes |
| BEC | Yes |
| BEC Maximum Burst Current | 8A |
| BEC Type | Switch Mode |
| BEC Voltage | 6V/7.4V |
| Brakes | Yes |
| Forward | Yes |
| Input Voltage | 2S LiPo for included motor (do not exceed 2S LiPo power with this motor) |
| Maximum Continuous Current | 40A |
| Motor Output Lead | 4 |
| Product Height | 1.3" (33 mm) |
| Product Length | 1.7" (43 mm) |
| Product Weight | 0.255 |
| Product Width | 2.1" (53 mm) |
| Programmable | Yes |
| Reverse | Yes |
| Technology | Smart |
| Amperage | 80A - 99A |
| BEC Continuous Current | 4 |
| Low-Voltage Cutoff Programmable | Yes |
| Motor Type | Brushless |
| Overload Protection | Yes |
| Water-Resistant | Yes |
| Product Application | Surface |
| ESC Type | Brushless |
| Part Type | Electronics |
| Output | 625W |
| Number of Poles | 4 |
| RPM/Volt (Kv) | 4000Kv |
| Drive Type | Forward/Brake/Reverse |
| Outer Diameter | 1.41" (36 mm) |
| Shaft Diameter | 0.125" (3 mm) |
| Motor Design | Inrunner |
| Maximum Burst Current | 550A |
| Max Input Voltage | 11.1V |
| Battery Input Lead | IC3 |
| Programming Options | Button, Programming Box, Smartlink App, On Screen Text Gen |
| Motor Class | 1/10 Scale |
| Constant Wattage | 250-499W |
| Integrated ESC | No |
| Kv Rating | 3000Kv or more |
| Sensor Type | Sensorless |
| Speed Control | Included |
| Sensored | No |
| Time Delay Brake | Yes |
| Efficiency | 81% |
Tags: Spektrum, SPMXSEMC02, Spektrum telemetry and sensor range, Spektrum Catalog, Spektrum Smart Technology, Spektrum ESCs, Spektrum Surface Electronics, RC-MODEL