Waterproof DC-DC Buck Converter IP67 Potted Step-Down Module, 8–100V Input, 3–60V Output, up to 120W

Overview

The EpevsPower J Series is a family of waterproof DC-DC buck converters that step a high battery or bus voltage down to a stable low voltage. Three potted ABS housings — J1, J2 and J3 — cover 36 W to 120 W, with input up to 100 V and fixed outputs from 3 V to 60 V. Synchronous rectification delivers up to 96% peak efficiency, so the module runs cool without a fan. Fully potted and rated IP67, it is built for vehicles, outdoor equipment, smart-home and small electronic devices that need clean power for sensors, controllers and other low-voltage loads.

What Is a DC-DC Buck Converter?

A DC-DC buck converter is a switching power module that converts a higher DC voltage into a lower, regulated DC voltage — for example 48 V to 12 V or 24 V to 5 V. Unlike a linear regulator, it switches the input on and off at high frequency and filters the result, so it wastes very little energy as heat. Modern synchronous buck converters reach 92–96% efficiency.

J Series Key Features

• Up to 100 V input, 120 W output — one series covers 12 V, 24 V, 36 V, 48 V, 60 V and 72 V systems.
• Up to 96% peak efficiency — latest synchronous rectification buck technology; natural cooling, no fan.
• Built-in MOSFET models: up to 5 A, no-load current under 2 mA — barely drains the battery when the load is off.
• External MOSFET models: up to 10 A continuous, 15 A peak — handles motor and inrush loads.
• Reverse input protection on built-in MOSFET models rated 48 V input and above.
• Four-way protection — input under-voltage, output over-current, output short-circuit and over-temperature.
• Over-temperature delayed start on external MOSFET models — the module waits to cool before restarting.
• Adaptive output power — strong load capacity that holds regulation across the full load range.
• IP67, fully potted ABS housing — dust-tight, waterproof, vibration- and impact-resistant, and electrically insulated.
• Compact, easy to mount — from 63.5 × 27.5 × 14 mm, with screw ears and pre-stripped flying leads.

Which J Series Housing Do I Need?

Choose by load power first, then by space:

• J1 — up to 36 W / 3 A. The smallest case for sensors, MCUs, GPS trackers, dash cams and USB power.
• J2 — up to 50 W (built-in) or 72 W (external MOSFET). For LED lighting, radios, routers and small pumps.
• J3 — up to 120 W / 10 A. For fans, audio amplifiers, light bars, wipers and multiple 12 V accessories.

Housing Comparison — J1 vs J2 vs J3

 How to Wire the J Series Buck Converter

1. Check the label — confirm the input range covers your battery’s full-charge voltage and the output matches your load.
2. Disconnect power before wiring.
3. Connect input: Red wire to battery positive (+), the input-side Black wire to battery negative (−). Add a fuse on the positive line close to the battery.
4. Connect output: Yellow wire to load positive (+), the output-side Black wire to load negative (−). Input and output share a common ground.
5. Insulate every joint with heat-shrink tubing to keep the IP67 rating at the connection.
6. Mount the module with two screws through the ears on a flat surface with some airflow; keep the leads pointing downward so water cannot run along them.
7. Power up and measure the output with a multimeter before connecting sensitive devices.

Applications

• Vehicles & fleets — 24 V trucks and buses powering 12 V radios, cameras, GPS, USB chargers.
• Golf carts, e-bikes and e-scooters — 36 V / 48 V / 72 V packs to 12 V lights, horns and displays.
• Forklifts, AGVs and industrial vehicles — stable 12 V or 24 V for controllers and sensors.
• Marine & RV — waterproof power for pumps, LED lights and electronics.
• Solar & off-grid systems — battery bank to 5 V / 12 V loads with near-zero standby drain.
• Smart home & IoT — low-voltage supply for sensors, microcontrollers and access-control devices.
• Telecom & security — 48 V DC to 12 V for cameras and network gear.

Why Choose EpevsPower

• Factory-direct — standard J Series and custom output voltages from one source.
• 100% automated testing and burn-in before shipment.
• Custom options — output voltage, wire length, connectors and private-label printing
• Samples and datasheets on request, reply within 24 hours.
• MOQ / lead time: 10PC, 5 Days