Simarine SC303 & SC503 Digital Shunt
User Manual V1.3
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 grey water.
SC303: An innovative combination of shunt and tank level module. It is an active combo shunt for the PICO battery monitor with 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 up to 75V systems. It is capable of measuring continuous current up to 300 A and is suitable for a maximal power of 3600 W at 12 V or 7200 W at 24 V.
SC503: A high precision combo shunt for the PICO battery monitor with 2x voltage inputs, 2x temperature inputs, 1x socket for a temperature sensor with a JST connector, and 1x current sensor up to 500A for up to 75V systems. It is capable of measuring continuous current up to 500 A and is suitable for a maximal power of 6000 W at 12 V or 12000 W at 24 V.
2. Safety
Electrical specialists 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, colorless liquid that will burn your eyes, skin, and clothing. Should the acid come in contact with eyes, skin, or clothing, wash it immediately with soap under fresh water for at least 15 minutes, and seek medical support immediately.
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. Make sure to keep sufficient ventilation around the battery.
3. Overview
A photograph of the Simarine SC503 digital shunt, showing its compact form factor with screw terminals for power and data, and a SICOM port.
The shunt module has the following connection points:
- A - Battery Input Side
- B - System Output Side
- C - 2x SiCOM port
- D - 1x JST socket for temperature sensor
- E - 2x Voltage & 2x Resistance input
4. Installation
CAUTION: Install the shunt module in a clean, dry place, protected from accidental spilling of liquids.
- Remove the shunt cover by unscrewing four screws on top of the shunt cover.
- To install the shunt, use the supplied voltage cables and find a place no further than 3 m away from the battery/battery bank. You can fix the shunt with the supplied screws using two holes on the bottom of the casing.
- Connect all cables.
- Place back the shunt cover and screw the four screws on the cover of the shunt unit.
4.1 Cables
For the SiCOM connection, use the supplied cable. If not possible, use the following table to determine the right cable type.
| Cable length | CABLES Cable type |
|---|---|
| < 5m | No limitations |
| >= 5m | 2x2x0.25 mm² Twisted pair (recommended) |
4.1.1 Power cable
Minimum power cable cross-section requirement at maximal temperature of insulation 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-section can damage the shunt, wiring, or cause a fire.
5. Connecting
For proper function of Simarine's SC303/SC503 digital shunt, it is necessary to take the following steps:
- Disconnect the battery/battery bank plus and minus terminals for safety reasons.
- Connect the shunt to Simarine's 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 batteries/battery bank minus or plus terminal through the shunt's IN terminal.
- Connect all consumers and charging sources to the OUT terminal on the shunt.
Each correctly connected shunt needs to be configured. This is done via PICO in an easy way. The configuration process is described in PICO's manual.
PICO manual & other user manuals: https://simarine.net/manuals
It is recommended that the shunt is installed in the negative line if possible.
CAUTION: After connecting the shunt, make sure that all the connections between cables and shunt are tight. Loose connections may cause sparks, heating, and even a fire. It may also damage the shunt.
5.1 SCX03 installed on the minus terminal of the battery
A schematic illustrating the installation of the SCX03 shunt on the negative terminal of a battery. It shows connections to a PICO display via a SICOM port, voltage sensing inputs to the battery terminals, and connections for accessories like motors, ignition switches, and sensors.
6. Technical specifications SC303 & SC503
SC303
| SC303 | |
|---|---|
| Operating | |
| Voltage range | 6 - 35 V |
| Temperature range | -20 - 70°C (-4 - 158 °F) |
| Power consumption at 12V | 0.8 mA |
| Current Measuring range | |
| 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 | Up to 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 | M 10 bolts |
SC503
| SC503 | |
|---|---|
| Operating | |
| Voltage range | 6 - 35 V |
| Temperature range | -20 - 70°C (-4 - 158 °F) |
| Power consumption at 12V | 1.2 mA |
| Current Measuring range | |
| 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 | Up to 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 | M 10 bolts |
7. Troubleshooting
7.1 Negative current values
If PICO is showing the wrong sign for current value, check if the shunt is correctly installed. This means the battery/battery bank minus (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 is 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 and is twisted.
- Check if the voltage sensing input is correctly installed and doesn't have the plus and minus terminals switched.
