Manufacturer Part Number: RTS
Remote temperature probe for use with the ProStar, TriStar, and all other Morningstar controllers that can use a battery temperature probe. For use with the ProStar the leads must be soldered to the circuit board, the TriStar is provided with a terminal strip for connection.
For maximum protection from harsh environments, the sensor is encapsulated in epoxy inside a power lug housing. The RTS is also protected from lightning surges and short circuits.
Do I need a Temperature Sensor? Maybe, but maybe not. If your batteries are at a different temperature than your controller (more than 10 degrees F - Morningstar recommends 5 degrees), then yes you probably should. For instance, if your controller is inside but your batteries are outside in the weather, the built-in temperature compensation would not be correct.