FingerTech BL40A AM32 Reversing ESC
FingerTech BL40A AM32 Reversing ESC
The FingerTech BL40A AM32 reversing ESC brings serious brushless power to your beetleweight drive system — 40A continuous, 3S–6S compatible, and running FingerTech‘s own optimized AM32 firmware for faster response and better low-end torque than BLHeli. Programmed for both forward and reverse, it’s the ESC that gives you full control of your drive motors or reversible weapon. Pair it with the Mega Spark or other brushless drive motor and go. (Note: weapon motors are generally single-direction).
$36.50
9 in stock (can be backordered)
AM32 Power — Forward, Reverse, Full Control
The FingerTech BL40A AM32 reversing ESC is a 40A brushless speed controller built for beetleweight combat robots that need full bidirectional control. Running FingerTech’s own customized AM32 firmware, it delivers faster response, better low-end torque, and more efficient power delivery than BLHeli equivalents. Whether you’re driving brushless drive motors or running a reversible weapon, this ESC handles it cleanly.
Why AM32?
AM32 is a modern open-source firmware platform designed specifically for brushless motor control. FingerTech has taken AM32 and tuned it for combat robotics — optimizing response and low-end torque for the demands of drive systems. The result is an ESC that responds faster and more predictably than the BL20A BLHeli ESC it replaces, with twice the current capacity for larger, more demanding motors.
Drive Motor Use
The reversing ESC is the right choice for brushless drive systems. Pair it with FingerTech‘s Mega Spark Brushless Gearmotors — available in 750KV, 1500KV, and 2300KV variants — or with other manufacturers’ brushless drive motors. You’ll need two reversing ESCs for a standard two-motor drive system.
Reversible Weapon Use
Need the option to reverse your weapon direction? The reversing ESC works with the F4006 740KV Brushless Outrunner and S2838 2970KV Brushless Inrunner, as well as other manufacturers’ brushless weapon motors. For standard single-direction weapon use, the FingerTech BL40A AM32 ESC is the more common choice — see the FAQ tab for more on why.
Wiring Notes
The BL40A reversing ESC has no onboard BEC — you’ll need a dedicated 5V BEC to power your receiver. Connect the three motor wires in any order; if the motor spins in the wrong direction, swap any two wires. The NightWing kit uses this ESC for drive motors, paired with the NightWing Electronics Kit — all wiring is documented in the NightWing build instructions.
Standard vs Reversing
Not sure which version you need? The standard FingerTech BL40A AM32 ESC is single-direction — ideal for weapon motors that only spin one way. This reversing version is programmed for both forward and reverse, making it the right choice for drive motors or any application where bidirectional control matters. The hardware and specs are otherwise identical.
Features
- 40A continuous / 45A burst — handles high-demand beetleweight drive and weapon motors
- FingerTech-optimized AM32 firmware for faster response and better low-end torque than BLHeli
- 3S–6S LiPo compatible — powers the FingerTech BL40A AM32 reversing ESC across a wide voltage range
- Compact and lightweight — 1.46in × 0.49in × 0.26in, 0.43oz (12.1g)
- 3.5mm bullet connectors — direct fit for most brushless combat motor wires
- Forward and reverse — full bidirectional control for drive and reversible weapons; for single-direction weapon use, see the FingerTech BL40A AM32 ESC
Specifications
| Specification | Value |
|---|---|
| Length | 1.46in (37.0mm) |
| Width | 0.49in (12.4mm) |
| Height | 0.26in (6.5mm) |
| Weight | 0.43oz (12.1g) |
| Voltage Range | 11.1–22.2V (3S–6S LiPo) |
| Continuous Current | 40A |
| Burst Current | 45A (<10 seconds) |
| Firmware | AM32 (FingerTech optimized) |
| Motor Connector | 3.5mm female bullet connectors |
| Motor Wire Length | 3.15in (8.0cm) |
| BEC | None — external 5V BEC required |
| Direction | Forward and reverse |
Frequently Asked Questions
What's the difference between the BL40A and the BL20A?
The BL40A runs AM32 firmware vs the BL20A's BLHeli, and delivers twice the current capacity — 40A continuous vs 20A. AM32 provides faster response and better low-end torque, making it the right choice for larger motors that can exceed the BL20A's current limits during spin-up or high-load drive situations.
What's the difference between the BL40A and the BL40A Reversing?
The Standard BL40A is single-direction — ideal for weapon motors that only need to spin one way. This reversing version is programmed for both forward and reverse, making it the right choice for drive motors or weapon systems where bidirectional control is needed. The hardware and specs are otherwise identical.
Why do most weapon builds use a single-direction ESC?
Most builders use a single-direction ESC for spinning weapons, and there are a couple of likely reasons. A single-direction ESC is simpler to configure and leaves less room for error — accidentally reversing a spinning weapon mid-fight could be dangerous and disorienting. There's also a radio failsafe consideration: a single-direction ESC defaults to off on signal loss, whereas a reversing ESC could theoretically default to an unintended state. That said, a reversing weapon ESC isn't without merit — some builders find it useful for unjamming a wedged weapon, or for drum weapons where direction flexibility has tactical value. These are plausible reasons rather than definitive rules; the combat robotics community has its own well-developed opinions on this.
Does the BL40A Reversing have a BEC?
No — there is no onboard BEC. You'll need a dedicated 5V BEC to power your receiver. This is common on higher-current ESCs and keeps power clean for noise-sensitive radio equipment.
Can I reprogram the BL40A Reversing?
Yes — the BL40A reversing ESC runs AM32 firmware and can be reprogrammed using a USB AM32 programmer. FingerTech ships it with optimized settings for combat robotics use, so most builders won't need to change anything out of the box. Advanced users can tune parameters like motor KV, timing, and braking to suit their specific setup.
