1. Introduction
Simarine's high precision SCX03 (SC303 & SC503) active digital shunt measures voltage, current, and temperature of the battery or battery bank. It is used for monitoring current draw of heavy consumers (inverters, bow and stern thrusters, anchor winches) and current generators (shore power chargers and solar panels). Additionally, it allows monitoring tanks for fuel, fresh, and grey water.
SC303: An innovative combination of shunt and tank level module. The SC303 is an active combo shunt for the PICO battery monitor, featuring 2x voltage inputs, 2x tank level or temperature inputs, 1x socket for a temperature sensor with a JST connector, and 1x current sensor up to 300A for systems up to 75V. It can monitor current draw from heavy consumers and generators, and also tanks. The SC303 is capable of measuring continuous current up to 300A and is suitable for a maximal power of 3600W at 12V or 7200W at 24V.
SC503: An innovative combination of shunt and tank level module. The SC503 is a high precision combo shunt for the PICO battery monitor, featuring 2x voltage inputs, 2x temperature inputs, 1x socket for a temperature sensor with a JST connector, and 1x current sensor up to 500A for systems up to 75V. The SC503 is capable of measuring continuous current up to 500A and is suitable for a maximal power of 6000W at 12V or 12000W at 24V.
2. Safety
Installation of Simarine electronics should be performed by electrical specialists with appropriate safety equipment. When working with batteries, wear protective clothing and eye protection.
CAUTION: Batteries contain acid, a corrosive liquid that can burn eyes, skin, and clothing. In case of contact, wash immediately with soap and fresh water for at least 15 minutes and seek medical support.
CAUTION: Do NOT connect anything to a damaged battery, as it could heat up, catch fire, or explode.
CAUTION: Lead-acid batteries can generate explosive gases during operation. Never smoke, allow flames, or sparks near the battery. Ensure sufficient ventilation around the battery.
3. Overview
The SCX03 is a compact electronic module designed for battery monitoring. It features robust terminals for main power connections and smaller terminals for sensor and communication inputs.
Port Identification:
- A: Battery (+) terminal
- B: Hub - GND (-) terminal
- C: 2x SiCOM ports for communication
- D: 1x JST socket for temperature sensor
- E: 2x Voltage and 2x Resistance inputs
4. Installation
CAUTION: Install the shunt module in a clean, dry place, protected from accidental spilling of liquids.
Installation Steps:
- Remove the shunt cover by unscrewing the four screws on top.
- Mount the shunt using the supplied screws in the two bottom holes. Position it no further than 3 meters away from the battery/battery bank.
- Connect all necessary cables.
- Replace the shunt cover and secure it with the four screws.
4.1 Cables
SiCOM Connection Cable Requirements:
| Cable Length | Cable Type |
|---|---|
| < 5m | No limitations |
| >= 5m | 2x2x0.25 mm² Twisted pair (recommended) |
4.1.1 Power Cable
Minimum Power Cable Cross-Section Requirements (Maximal Insulation Temperature 70°C / 160°F):
| Continuous Current | Area |
|---|---|
| 500 A | 220 mm² |
| 400 A | 150 mm² |
| 300 A | 95 mm² |
| 200 A | 50 mm² |
| 100 A | 25 mm² |
CAUTION: Failure to use the correct cable cross-section can damage the shunt, wiring, or cause a fire.
5. Connecting
Follow these steps for proper function of Simarine's SC303/SC503 digital shunt:
- Disconnect the battery/battery bank positive and negative terminals for safety.
- Connect the shunt to Simarine's PICO via the SiCOM port.
- Connect the shunt's voltage sensing input to a battery terminal.
- Connect the temperature sensor to the shunt and place it near the battery/battery bank (optional).
- Connect the battery/battery bank negative or positive terminal through the shunt's IN terminal.
- Connect all consumers and charging sources to the OUT terminal on the shunt.
Each correctly connected shunt requires configuration, which is performed via the PICO device. Refer to the PICO manual for the configuration process.
Recommendation: It is recommended that the shunt is installed in the negative line if possible.
CAUTION: After connecting the shunt, ensure all connections between cables and the shunt are tight. Loose connections may cause sparks, heating, fire, or damage to the shunt.
5.1 SCX03 Installed on the Minus Terminal of the Battery
Diagram Description: This diagram illustrates the typical installation of the SCX03 shunt within a marine electrical system. The PICO battery monitor is connected to the SCX03 shunt via a SiCOM communication cable. The SCX03 shunt is installed in the negative line of the main battery bank. The positive terminal of the battery bank connects to the SCX03's IN terminal. All electrical loads (consumers like motors, refrigerators, lights, navigation equipment, inverters) and charging sources (e.g., solar panels) are connected to the SCX03's OUT terminal. Optional temperature sensors and tank level sensors can also be connected to the SCX03.
6. Technical Specifications SC303 & SC503
SC303 Specifications:
| Parameter | Value |
|---|---|
| Operating | |
| Voltage range | 6 – 35 V |
| Temperature range | -20 – 70°C (-4 – 158 °F) |
| Power consumption at 12V | 0.8 mA |
| Current Measuring | |
| Per channel | 0.01 – 320 A |
| Accuracy | ± 0.6% |
| Resolution | 0.01 A |
| Sampling rate | 100 ms |
| Maximal current | |
| Continuous | 300 A |
| Peak current (<1min) | 700 A |
| Peak current (<5min) | 400 A |
| Voltage drop at 300 A | 50 mA |
| Maximal voltage on connections | 35 V |
| Voltage inputs | |
| Range | 0 – 75 V |
| Accuracy | ± 0.2% |
| Resolution | 1 mV |
| Sampling rate | 100 ms |
| Resistance inputs | |
| Range | 0 Ohm – 65 kOhm |
| Accuracy | ± 3% |
| Temperature sensor - NTC 10k | |
| Range | -15 – +80 °C |
| Accuracy (-10 – 60 °C, 14 – 140 °F) | ± 3% |
| Connectivity | |
| Batteries | 1 |
| Temperature sensors | 3 |
| Voltage sensors | 2 |
| SiCOM RJ9 Sockets | 2 |
| Installation and Dimensions | |
| Dimensions | 120 x 120 x 60 mm (4.72 x 4.72 x 2.36 in) |
| Battery connection | M10 bolts |
SC503 Specifications:
| Parameter | Value |
|---|---|
| Operating | |
| Voltage range | 6 – 35 V |
| Temperature range | -20 – 70°C (-4 – 158 °F) |
| Power consumption at 12V | 1.2 mA |
| Current Measuring | |
| Per channel | 0.01 – 700 A |
| Accuracy | ± 0.6% |
| Resolution | 0.01 A |
| Sampling rate | 100 ms |
| Maximal current | |
| Continuous | 500 A |
| Peak current (<1min) | 1000 A |
| Peak current (<5min) | 700 A |
| Voltage drop at 300 A | 50 mA |
| Maximal voltage on connections | 35 V |
| Voltage inputs | |
| Range | 0 – 75 V |
| Accuracy | ± 0.2% |
| Resolution | 1 mV |
| Sampling rate | 100 ms |
| Resistance inputs | |
| Range | 0 Ohm – 65 kOhm |
| Accuracy | ± 3% |
| Temperature sensor - NTC 10k | |
| Range | -15 – +80 °C |
| Accuracy (-10 – 60 °C, 14 – 140 °F) | ± 3% |
| Connectivity | |
| Batteries | 1 |
| Temperature sensors | 3 |
| Voltage sensors | 2 |
| SiCOM RJ9 Sockets | 2 |
| Installation and Dimensions | |
| Dimensions | 120 x 120 x 60 mm (4.72 x 4.72 x 2.36 in) |
| Battery connection | M10 bolts |
7. Trouble Shooting
7.1 Negative Current Values
If the PICO is showing the wrong sign for the current value, check if the shunt is correctly installed. This means the battery/battery bank minus (or optionally plus) terminal is connected to the IN terminal on the shunt. If this is not the case, you can reinstall the shunt or simply switch the IN and OUT terminals via the shunt configuration on PICO.
7.2 Shunt Not Visible on PICO
If the shunt is not visible on PICO's menu, check the following:
- Is the shunt properly connected via the SiCOM port to the PICO?
- If you are using your own SiCOM cable, make sure it has the right square connector and is twisted.
- Check if the voltage sensing input is correctly installed and doesn't have the plus and minus terminals switched.
For more information and other user manuals, visit: https://simarine.net/manuals
