Train Horn Compatible with DeWalt 20V Battery

A complete portable horn. No installation required.

This is a complete cordless device powered by your compatible DeWalt 20V MAX battery. You do not need a separate drill, impact driver, vehicle wiring, or an installed air system.

The box contains the horn base and trumpets. Screw the trumpets into the base by hand, without additional tools, then connect your battery. Press the built-in trigger as you would on a drill or impact driver, or press the button on the included wireless remote to sound the horn. Battery and charger are optional extras, sold separately.

Boss Horn’s story began in late 2022.

Boss Horn began developing and producing its first train horns for DeWalt batteries in late 2022. At the time, comparable portable devices were operated by a drill-style trigger. Boss Horn introduced wireless remote control to this category, giving customers another way to activate the horn and opening up many more uses.

Comparable remote-equipped horns from Boss Horn’s closest competitor followed approximately nine months later. By then, Boss Horn’s product was already reaching customers in the United States and other countries. The team continued developing the design to address the shortcomings of those early versions.

Metal trumpets. Built for lasting use.

Early devices in this category often used inexpensive plastic trumpets that fell short in durability and sound quality. The horns use metal-alloy trumpets with a powder-coated finish for a full horn sound and long-term durability.

The alloy and protective finish resist corrosion and rust, helping the trumpets stand up to long-term use.

From modified power tools to Boss Horn’s own housing.

Boss Horn’s original approach used genuine DeWalt drill and impact-driver housings. This provided a compatible battery connection and a familiar power-tool appearance, but the housing was never designed around Boss Horn’s horn components.

Building a horn meant dismantling a complete tool and removing its motor, gearbox, switches, and other internals, leaving the shell and battery connector. Those unused components went to recycling, creating unnecessary material waste.

In mid-2026, Boss Horn introduced its purpose-built housing, designed specifically for the horn. The air-compressor motor fits securely inside instead of moving around or working loose. Boss Horn selected high-quality materials of the type used for power-tool housings, while giving the device its own style and a more precise internal fit.

This change improved assembly consistency and reduced defects, failures, and returns. It also eliminated the need to dismantle a complete power tool to build each horn.

A custom control board, developed over a year.

Boss Horn’s custom horn-control board was introduced in mid-2025, following approximately a year of development, around ten design iterations, and extensive revisions. The current housing, control board, and updated standard remote are used across all models in this DeWalt-compatible lineup.

The board brings together volume control, motor protection, and independent battery protection. Development continues as the Boss Horn team refines the electronics and prepares further revisions.

Choose the volume level that fits the moment.

Two-trumpet models have two volume settings. Four- and five-trumpet models have three. Volume control is built into the device rather than relying on a different battery or a different horn assembly.

Motor protection that addresses an early failure point.

Heavy use could overheat the motor in earlier designs. Excessive heat could deform the motor-brush holders, causing the brushes to bind and the motor to seize.

Boss Horn’s control board tracks motor running time to manage heat buildup. When the protection limit is reached, it stops the motor and temporarily locks out operation for cooling. Compared with Boss Horn’s earlier designs, Boss Horn has seen approximately 95% fewer motor failures caused by overheating.

Normally, allow approximately 10 minutes before continuing. The cooling timer only advances while a battery is connected. If you remove the battery during the lockout, reconnect it and leave it connected for 10–15 minutes so the timer can complete—even if the motor has already cooled down. A cool motor alone does not clear a lockout whose timer has not finished.

Deep-discharge protection, in two stages.

First, the board checks battery voltage when the motor starts and while it runs. If voltage is too low, it blocks the motor from starting or continuing to draw power, rather than taking the battery’s remaining charge.

Second, the board manages power to the wireless receiver inside the horn. In earlier versions, the receiver remained powered continuously while waiting for a signal. A battery left connected could gradually discharge so deeply that it would no longer accept a charge. The new receiver power-management system addresses that idle drain.

Three power modes for the wireless receiver.

Always on keeps the receiver powered and ready for remote operation. Always off disables power to the receiver. Standard mode keeps it powered for three hours after the battery is connected, or for three hours after the horn was last sounded.

In Standard mode, sounding the horn restarts that three-hour window. After three hours without use, the receiver switches off automatically. This three-hour receiver timer is separate from the motor’s cooling timer.

Tested for months of connected storage.

Boss Horn’s tests showed that, in Standard mode, a battery can remain connected to the horn for months without damage from deep discharge. In some tests, the battery remained connected for more than a year. Automatic receiver shutoff prevents continued receiver drain during storage.

We still recommend disconnecting the battery after use and before storage to prevent accidental activation. While the receiver is powered, an unintended radio signal could activate a connected horn—for example, while it is sitting in a garage. The disconnect recommendation addresses unexpected activation; the electronics independently protect the battery from deep discharge.

An upgraded remote with a longer reach.

Boss Horn’s earlier, very compact remotes offered approximately 160 feet of range. The updated standard remote is only slightly larger, but provides up to 300 feet of range and can reach farther in favorable open-area conditions.

We also improved signal quality and reliability, particularly where interference affects wireless operation. Actual range depends on obstacles and local interference. One updated standard remote is included with every horn.

Why does the battery connector have only two contacts?

You may notice that your DeWalt power tools have more battery contacts than Boss Horn’s horn. Boss Horn’s connector uses only the positive and negative contacts to receive power.

We developed the horn’s protection logic independently, without relying on access to DeWalt’s proprietary battery-communication system. Boss Horn’s own electronics monitor voltage, control power draw, and decide when to switch the device off. They do not need to communicate with the battery through additional data contacts.

That is why two power contacts are sufficient for this design. It also means the same onboard deep-discharge protection works with both original DeWalt 20V MAX batteries and compatible aftermarket alternatives.

Why the connector has two contacts

The horn needs only positive and negative power contacts. Its own onboard electronics monitor voltage and protect against deep discharge independently of additional battery data contacts. The same protection applies to original DeWalt 20V MAX batteries and compatible aftermarket alternatives.

• Positive and negative: supply power to the horn.
• Independent electronics: handle low-voltage protection without relying on the battery’s additional data contacts.
• Original or aftermarket: the same onboard protection applies to compatible batteries of either type.

Two ways to sound the horn

• Built-in trigger: press the trigger on the horn handle to activate it.
• Included wireless remote: up to 300 ft range.
• Optional long-range remote: up to 2,000 ft range, sold separately.

Radio range depends on obstacles, interference and the surrounding environment.

Selectable volume

Use the volume setting that suits the moment; the available number of levels depends on your trumpet configuration.

Your selected model: 2 volume levels. Two-trumpet models have two levels; four- and five-trumpet models have three.

If motor protection pauses operation

The board uses motor run time to manage heating, rather than relying on communication with a DeWalt tool. A protection lockout pauses the motor when a cooling interval is needed.

1. Leave the battery connected. Allow about 10 minutes before continuing.
2. If you removed the battery during lockout, reconnect it. Wait 10–15 minutes for the cooling timer to finish, even if the motor has already cooled.

Battery protection at startup and in standby

Two protection stages work together: voltage checks during use and managed radio-receiver power while the horn waits for a remote signal.

• Motor voltage checks: the board checks battery voltage at startup and during operation. Low voltage prevents the motor from draining a depleted pack further.
• Receiver power management: radio standby power is controlled separately to reduce the drain associated with leaving a receiver on continuously.

Choose the receiver power mode

Always on

The wireless receiver stays powered.

Always off

The wireless receiver is switched off.

Standard

The receiver stays active for three hours after connecting the battery or sounding the horn. Every activation starts a new three-hour window; after it expires, the receiver switches off automatically.

After use: disconnect the battery before storage to help prevent unintended activation from radio signals.