Much more accurate than the sensor built into my charge controller, probably because it can be placed directly on the battery case rather than measuring ambient air temperature. The plug wiring of the connector is a little flimsy but has the benefit of being easier to cut to length and reattach to the connector. After cutting the cable short, I lubricated the cores with flexible sealant for strain relief. Seems to be holding up after a few months of use. Incidentally, this does not only work with MPPT controllers. It works great (as confirmed by my infrared temperature sensor) with my Viewstar VS3024BN PWM controller.