Tigo MLPEs (module level power electronics) are intelligent devices that may perform Optimization, Rapid Shutdown (RSD) and data function (depending upon the model). These units also provide basic current and voltage mitigation functions to protect themselves from accidental damage and weather events.
Since MLPEs receive their running power from the PV Module, they will remain active, as long as they are plugged in (and the sun is shining). Hence, these basic safety functions are only active when the unit (itself) is active.
This is important to know, because disconnecting/reconnecting the unit from and to the PV Module requires special care.
⚠️ IMPORTANT: Never disconnect an MLPE, while still connected to the string!
Employing the proper procedure will ensure both personal safety, and product safety.
Note: The instructions (below) apply to all Tigo retrofit MLPEs, including:
- MM-ES (Maximizer series)
- MM-2ES (Dual Maximizer series)
- TS4-R (original retrofit series)
- TS4-A Flex (Optimizer, Safety and Monitoring series)
- TS4-F (Fire Safety series)
- TS4-2F (dual Fire Safety series)
Disconnecting Tigo MLPE
Following these directions will ensure a safe removal of the Tigo MLPE for testing and/or replacement.
- Perform RSD or enact PV Safe, to drop the string voltage to safety levels.
- (important for parallel strings) Disconnect string and/or remove any string fuse(s), before heading out to the unit.
- Disconnect the old optimizer from the string output, before disconnecting the unit from the PV Module. This will reduce any current damage from a ground discharge or shorting issue.
Note: At this stage, the Installer may perform an MLPE output test, by reactivating the system and testing the output cable connectors
- Disconnect the old optimizer from the panel (once the output cables have been disconnected).
Note: At this stage, the installer may safely perform a PV Module (panel) test.
Reconnecting (or Replacing) Tigo MLPE
Reconnection or replacing a Tigo MLPE is the same process, but in reverse.
- Connect the Tigo MLPE to the PV Module/Panel.
(this will activate the new unit, if in sunny conditions)
- Connect the MLPE output cables to the string.
(at this point, installer can test the MLPE output to ensure it's functioning)
- Measure output voltage of the string to make sure it has the proper voltage
Important for TS4-F Fire Safety systems that have a safety voltage (.6 volts per unit)
- Once all strings have the same/expected voltage, they can be reconnected/fuses put back in.
- If string voltage is incorrect, determine the reason and employ a correction, before reconnecting and reactivating system.
- Uneven Parallel Strings (parallel strings with different voltage readings) should not be reconnected until a correction has been employed. Uneven parallel strings can incur reverse current issues.
- Keep track of the serial number locations! If many MLPEs are being moved or replaced, good note keeping will yield a precise system map (once the System Layout is rebuilt, online).
- Update the System Layout with any new locations.
For more info: Updating a Serial Number for an MLPE Replacement