📋 Overview
The EM15-80S1203 is a waterproof, non-isolated DC-DC step-down (buck) converter that takes a wide 15V to 80V DC input and delivers a stable 12V DC output at up to 3A (36W maximum). It's designed to sit inline on a flying-lead cable, dropping a higher, often noisy or variable voltage source down to a clean, regulated 12V rail for your equipment.
This module is fully potted and sealed in a rugged, waterproof metal housing rated IP68, making it a great fit for automotive, marine, solar, and industrial applications where the converter may be exposed to moisture, vibration, or dust. Built-in protections — including reverse polarity, over-current, over-temperature, and short-circuit hiccup protection — help keep both the converter and your connected equipment safe.
⭐ Key Features
- Wide 15-80V DC Input Range — Works with a broad range of unregulated or variable DC power sources, from 24V systems up to 72V/80V battery banks
- Stable 12V DC Output — Delivers up to 3A (36W) of clean, regulated 12V power
- 91% Typical Efficiency — Minimizes heat generation and wasted power at 48V input
- IP68 Waterproof Housing — Fully epoxy-sealed metal enclosure suitable for outdoor, marine, and harsh-environment use
- Built-In Protections — Reverse polarity, input transient absorption, over-current, over-temperature, and hiccup-mode short-circuit protection
- Compact & Lightweight — Small footprint (48.5mm body length) at approximately 50g, easy to mount or tuck into tight enclosures
🔌 Wiring & Connections
This converter uses flying leads for both input and output — there is no connector or terminal block.
| Wire Color | Function |
|---|
| Red | +V Input (15-80V DC) |
| Black (input side) | -V Input (Ground) |
| Yellow | +V Output (12V DC) |
| Black (output side) | -V Output (Ground) |
⚠️ Important: Double-check polarity before connecting power. While this converter includes reverse polarity protection, correct wiring on the first try helps avoid nuisance trips and ensures your equipment powers up as expected.
⚠️ Critical: Match Your Input Power to Your Output Power
As with any DC-DC converter, your input power source must be able to supply at least as much power as your load will draw from the output. Since this converter is about 91% efficient, a simple rule of thumb is:
Required Input Power ≈ Output Power ÷ 0.91
At full rated output (36W), your input source needs to supply at least 36W ÷ 0.91 ≈ 39.6W. At 24V, that's roughly 1.65A of available input current; at 48V, roughly 0.83A.
If the input source can't keep up, the converter will fold back the output voltage rather than deliver the full 12V. For example, if your load draws 3A at 12V (36W) but your input source can only provide 24V at 1A (24W), the converter can only deliver about 8V at that current — not the full 12V.
⚠️ Important: Always size your power source with headroom — at least 20-25% more current capacity than your calculated requirement.
📊 Specifications
| Model Number | EM15-80S1203 |
| Input Voltage | 15-80V DC |
| Maximum Input Voltage (Continuous) | 80V DC |
| Output Voltage | 12V DC |
| Maximum Output Current | 3A |
| Maximum Output Power | 36W |
| Efficiency | 91% typical (@ 48V input, 25°C) |
| No-Load Current | <100mA |
| Output Ripple & Noise | 18-22mVp-p (Vin=15-80V, Iout=3A, 20MHz bandwidth) |
| Overvoltage Protection | 82V @ 25°C (TVS clamp) |
| Short-Circuit Protection | Hiccup mode; undamaged after 4-hour long-term short circuit |
| Isolation | Non-isolated |
| Switching Frequency | 220±10 kHz |
| Operating Ambient Temperature | -40°C to +50°C |
| Shell (Case) Temperature | -40°C to +80°C (over-temperature protection resumes operation once shell cools below 80°C) |
| Storage Temperature | -55°C to +100°C |
| Waterproof Rating | IP68 |
| Cooling | Natural convection (no fan) |
| MTBF | ≥200,000 hours (@ 48V input, 3A output) |
| Input & Output Wire Length | Approx. 15cm (6 inches) |
| Input & Output Wire Size | 22 AWG |
| Body Dimensions | Approx. 48.5 × 25 × 20 mm (1.91 x 0.98 x 0.79 inches) L × W × H |
| Overall Length (incl. mounting tabs) | Approx. 65 mm (2.56 inches) |
| Weight | Approx. 50g (1.8oz) |
📦 What's in the Box
- 1x EM15-80S1203 15-80V to 12V 3A DC-DC Waterproof Buck Converter
🎯 Typical Applications
- Electric vehicles (EVs) and golf carts/forklifts needing regulated 12V accessory power
- Solar and alternative energy systems
- Boats and yachts (thanks to the IP68 waterproof housing)
- Industrial equipment and telecommunications gear
- Powering 12V accessories (lighting, detectors, gauges) from a higher-voltage battery bank or supply
⚠️ Important Notes
- Verify input voltage stays within 15-80V DC and never exceeds 80V continuous
- Double-check polarity before connecting power — red/black are input, yellow/black are output
- Cooling is passive (natural convection) — ensure adequate airflow, especially at higher loads
- If output voltage sags below 12V, your input source likely can't supply enough power — see the power-matching section above
📄 Documentation & Resources
Sold and supported by Envistia Mall. Shipped from the United States. Please refer to the linked User Guide for full wiring instructions, specifications, and safety information. Envistia Mall is not liable for damage resulting from improper wiring, incorrect voltage, or misuse of this product. Always follow proper electrical safety practices when working with power converters and connected components.
