The OutBack Remote Temperature Sensor (RTS) is essential for proper battery charging. All OutBack Power products with integrated battery charging have temperature compensation systems built in which benefit from the installation of the RTS (included with inverter/chargers). With the RTS, you can make sure that your OutBack Power System knows the precise battery temperature, so it can recharge your batteries safely and efficiently. If your system has multiple OutBack products connected to one HUB4 or HUB10, only a single RTS needs to be installed.