Battery Temperature Sensor for Systellar Solar Charge Controllers
Charge your batteries correctly at every temperature
Battery charging voltage is temperature dependent. A battery that is hot needs a lower charging voltage; a battery that is cold needs a higher one. Without a temperature reading, a charge controller has to assume a fixed battery temperature — which means your batteries are being overcharged in summer and undercharged in winter.
The Systellar Battery Temperature Sensor is an optional accessory that measures the actual temperature of your battery bank and feeds it back to the charge controller, so charging voltages are adjusted continuously to suit real conditions. The result is a properly charged bank and longer battery life.
Why fit a temperature sensor
- Charging voltage automatically compensated for actual battery temperature
- Prevents overcharging and excessive water loss in hot weather
- Prevents chronic undercharging and sulphation in cold weather
- Extends usable battery bank life and protects your investment
- Plug-and-play — no configuration or calibration needed
How to install the sensor
- Clean the surface. Wipe the side or top wall of your battery bank to remove any dust or grease.
- Attach the probe. Use double-sided adhesive tape to firmly paste the sensor probe onto the side of the battery.
- Connect to the controller. Plug the 4-pin RJ11 connector at the end of the sensor cable into the designated battery temperature sensor socket on the left side of your Systellar charge controller.
Default behaviour
If the sensor is left unplugged, the charge controller automatically falls back to its standard charging parameters, calibrated for 25 °C. Your system will continue to work normally without the sensor — you simply lose the benefit of temperature compensation.
Specifications
| Function | Battery temperature measurement for charging voltage compensation |
| Connector | 4-pin RJ11 |
| Controller port | Battery temperature sensor socket, left side of the charge controller |
| Mounting | Double-sided adhesive tape onto the battery side or top wall |
| Default without sensor | Standard charging parameters calibrated for 25 °C |
| Compatibility | Systellar solar charge controllers fitted with an RJ11 temperature sensor socket |
| Wire Length | Standard length 3 meter |
Compatibility notice
This sensor is designed for Systellar brand solar charge controllers that provide a 4-pin RJ11 battery temperature sensor socket. If you are unsure whether your controller has this socket, check the left side of the unit or write to us before ordering.
In the box
- 1 × Battery temperature sensor probe with cable and 4-pin RJ11 connector (3m length)
- Double-sided adhesive tape for mounting
Installation questions? Contact info@systellar.in.