Why Doesn’t My Charge Controller Work When I Connect It To My PV Array? – 5/3/2024


When installing an off-grid solar system, it is recommended that you connect components in the following order:  

  1. Battery to solar charge controller
  2. PV array to solar charge controller
  3. Electrical load to solar charge controller

And when disconnecting, you reverse that order. The Battery provides power to the controller to turn it on and allow it to function, so always make sure that solar and loads are disconnected before connecting or disconnecting the battery from the controller. This applies to all Morningstar controllers.  Additionally, connections between the battery, load, array, and the charge controller should have disconnect switches and over current protection such as a fuse or DC rated circuit breaker. 

Unfortunately, some installers who don’t read their manuals, mistakenly connect the PV array first to the controller.  After making this connection they are surprised to discover that their charge controller does not power on.  Worse yet, they might damage the charge controller, even if using the right modules, since the charge controller is not first connected to the battery to power it on and allow its electronics to effectively regulate the power it receives from the array.  

Please remember and spread the word to others to connect the battery first in order to avoid this error.