📋 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) |
🎯 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
🛠️ Troubleshooting
- Output voltage is lower than 12V: Your input power source likely can't supply enough current — see the power-matching section above.
- Converter shuts off and restarts repeatedly: This is normal hiccup-mode behavior during a short-circuit or overload condition. Disconnect the load, check your wiring for shorts, and reconnect.
- No output at all: Confirm your input voltage is within 15-80V DC and that the red/black input wires are correctly polarized.
- Converter feels hot to the touch: This is expected under sustained high loads since cooling is passive (natural convection). Ensure adequate airflow and avoid enclosing the converter in a sealed, insulated space.
📚 Documentation & Resources
- EM15-80S1203 Datasheet (PDF)
- EM15-80S1203 Mechanical Drawing (PDF)
- EM15-80S1203 STEP File (3D Model)
🏪 Where to Buy
Buy the EM15-80S1203 15-80V to 12V 3A DC-DC Buck Converter at Envistia Mall.
- 📦 Fast US Shipping
- 🔄 Hassle-Free Returns
- 📧 Responsive Customer Support
⚠️ Disclaimer
This guide is provided for educational purposes to help you get the most out of your EM15-80S1203 DC-DC converter. Envistia Mall is not responsible for any damages or losses resulting from improper installation, incorrect wiring, or use outside the rated specifications of this product. Always follow proper electrical safety practices, including verifying polarity and voltage ratings before connecting power, and ensure adequate airflow around the converter during operation. Specifications are based on manufacturer data and are subject to change without notice.