Simarine SC303 & SC503 User Manual
Version 1.48
1. Introduction
Simarine's high precision SCX03 (SC303 & SC503) active digital shunt measures voltage, current, and temperature of the battery or battery bank. It can be 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 gray water.
SC303: An active combo shunt for PICO battery monitor with 2 voltages, 2 tank levels or temperature, 1 socket for temperature sensor with JST connector and 1 current sensor up to 300A for up to 75V systems. It can measure continuous current up to 300A and is suitable for a maximal power of 3600W at 12V or 7200W at 24V.
SC503: A high precision combo shunt for PICO battery monitor with 2 voltage, 2 temperature, 1 socket for temperature sensor with JST connector and 1 current sensor up to 500A for up to 75V systems. It can measure continuous current up to 500A and is suitable for a maximal power of 6000W at 12V or 12000W at 24V.
2. Safety
Only qualified electricians with proper safety equipment should perform the installation of Simarine electronics. When working with batteries, wear protective clothing and eye protection.
CAUTION: Batteries contain acid, a corrosive liquid that can burn eyes, skin, and clothing. If acid contacts eyes or skin, wash with lukewarm water and seek immediate medical attention.
CAUTION: Do NOT connect anything to a damaged battery. 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 shunt features the following connection points:
- A - Battery (+)
- B - Hub - GND (-)
- C - 2 SiCOM ports
- D - 1 JST socket for the temperature sensor
- E - 2 voltage & 2 resistance inputs
4. Installation
CAUTION: Install the shunt module in a clean and dry place protected from accidental spilling of liquids.
- Remove the shunt cover by unscrewing the four screws on top.
- Use the supplied voltage cables and find a location no further than 3 meters from the battery/battery bank.
- Fix the shunt using the supplied screws through the two holes on the bottom of the casing.
- Connect all cables.
- Replace the shunt cover and screw the four screws back on.
4.1 Cables
For SiCOM connection, use the supplied cable. If not possible, use the following table to determine the correct cable type:
| Cable length | Cable type |
|---|---|
| < 5 m | No limitations |
| >= 5 m | 2 x 2 x 0.25 mm² twisted pair (recommended) |
4.1.1 Power cable
Minimum power cable cross-section requirement at a maximal insulation temperature of 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 observe the required cable cross-sections can damage the shunt, wiring, or cause a fire.
5. Connecting
For proper function of the Simarine SC303/SC503 digital shunt, follow these steps:
- For safety reasons, disconnect the battery/battery bank plus and minus terminals.
- Connect the shunt to the Simarine PICO via the SiCOM port.
- Connect the shunt 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 minus (or plus) terminal through the shunt IN terminal.
- Connect all consumers and charging sources to the OUT terminal on the shunt.
Each correctly connected shunt needs to be configured using the PICO unit. The configuration process is described in the PICO manual.
Find the PICO manual and other user manuals at: https://simarine.net/manuals
It is recommended that the shunt is installed in the negative line if possible.
CAUTION: After connecting the shunt, ensure all cable-to-shunt connections are secured. Loose connections may cause sparks, heating, fire, or damage to the shunt.
5.1 SCX03 installed on the minus terminal of the battery
A diagram illustrates the SCX03 installed on the minus terminal of the battery.
6. Technical specifications SC303 & SC503
SC303 Specifications
| Parameter | Value |
|---|---|
| Operating | |
| Voltage range | 6-35V |
| Temperature range | -20 to +70°C (-4 to +158°F) |
| Power consumption at 12V | |
| Operating | 0.8 mA |
| Current measuring range | |
| Per channel | 0.01-320A |
| Accuracy | ±0.6 % |
| Resolution | 0.01 A |
| Sampling rate | 100 ms |
| Maximal current | |
| Continuous | 300A |
| Peak current (<1 min) | 700A |
| Peak current (<5 min) | 400A |
| Voltage drop at 300A | 50 mA |
| Maximal voltage on connections | 35 V |
| Voltage inputs | |
| Range | 0-75V |
| 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 to +80°C |
| Accuracy (from -10 to +60°C, from 14 to 140°F) | ±3 % |
| Connectivity | |
| Batteries | Up to 1 |
| Temperature sensors | Up to 3 |
| Voltage sensors | Up to 2 |
| SiCOM RJ9 sockets | 2 |
| Installation and dimensions | |
| Dimensions | 125 x 70 x 22 mm (4.92 x 2.75 x 0.86 in) |
| Battery connection | M10 bolts |
SC503 Specifications
| Parameter | Value |
|---|---|
| Operating | |
| Voltage range | 6-35V |
| Temperature range | -20 to +70°C (-4 to +158°F) |
| Power consumption at 12V | |
| Operating | 1.2 mA |
| Current measuring range | |
| Per channel | 0.01-700A |
| Accuracy | ±0.6 % |
| Resolution | 0.01 A |
| Sampling rate | 100 ms |
| Maximal current | |
| Continuous | 500A |
| Peak current (<1 min) | 1000A |
| Peak current (<5 min) | 700A |
| Voltage drop at 300A | 50 mA |
| Maximal voltage on connections | 35 V |
| Voltage inputs | |
| Range | 0-75V |
| 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 to +80°C |
| Accuracy (from -10 to +60°C, from 14 to 140°F) | ±3 % |
| Connectivity | |
| Batteries | Up to 1 |
| Temperature sensors | Up to 3 |
| Voltage sensors | Up to 2 |
| SiCOM RJ9 sockets | 2 |
| Installation and dimensions | |
| Dimensions | 125 x 70 x 22 mm (4.92 x 2.75 x 0.86 in) |
| Battery connection | M10 bolts |
7. Troubleshooting
7.1 Negative current values
If the PICO is showing the wrong sign for the current value, check if the shunt is correctly installed. Ensure the battery/battery bank minus (or plus) terminal is connected to the IN terminal on the shunt. If not, reinstall the shunt or switch the IN and OUT terminals via the shunt configuration on the PICO unit.
7.2 Shunt is not visible on PICO
If the shunt is not visible in the PICO menu, check the following:
- Is the shunt properly connected via the SiCOM port to the PICO unit?
- If using your own SiCOM cable, ensure it has the correct square connector and is twisted.
- Check if the voltage sensing input is correctly installed and that the plus and minus terminals are not switched.
