Can I use TS4 in an off-grid system? (i.e. with a charge controller)

Yes, TS4 is compatible with any inverter or charge controller that has its own MPPT functionality. The list of inverters/charge controllers that Tigo is currently compliance tested with is available here.

Rapid Shutdown Note: For an off-grid installation to support rapid shutdown, power your CCA/CC (Cloud Connect Advanced/Cloud Connect) via its own power supply with a switch. Then to shutdown the system's modules:

1. Switch off/disconnect the CCA from its power supply
2. Turn off the charge controller.

The above two steps will send the system into shutdown mode.

To reactivate the system after rapid shutdown:

1. Switch on/reconnect the CCA to its power supply
2. Turn on the charge controller

The above two steps will bring the system's modules back online

For more about rapid shutdown, see this article.