Can a GT inverter be attached to a grid?

While the grid is attached you have a large sink to push current into, so generally not a problem (Hawaii and California disagree and have formalized frequency shifting rules so they can control GT inverters). The problem is when the grid goes out your backup system disconnects from the grid so it doesn't backfeed into the grid.

Will a grid tie inverter work with an Offgrid inverters?

The grid tie inverter will happily co-exist with the offgrid inverter (proven by myself and others) and backfeeding excess power to the batteries can be prevented by the use of in-line rectifier diodes: Rectifier diodes will only conduct electrical current in one direction.

Can a spare GTI help an off grid inverter?

The objective - Reuse one of my spare GTIs to assist an off grid inverter in a totally off grid setup, with both running on the same circuit. This would save a lot of money on buying additional off grid inverter capacity. Cheap off grid inverters seem to be quite unreliable, reducing its load will no doubt help.

How does an off-grid inverter work?

A suitable Off Grid inverter with frequency shift support will, once the the maximum draw of the circuit has been reached, alter its frequency in order to signal the GTI to reduce its voltage to a level where it no longer supplies power to the circuit. Hence preventing overload.

Is a GTI a grid or a low frequency inverter?

I use a low frequency (LF) inverter and a good feature of these is that they are bidirectional. So a GTI doesn't care whether it is off grid or on grid, as long as there is a grid. You can't just plug it all together and walk away. A GTI is on or off and will supply all the power it can into what it thinks is an infinite grid.

Are cheap off grid inverters reliable?

Cheap off grid inverters seem to be quite unreliable, reducing its load will no doubt help. Observations so far - A pure sine wave inverter, attached to a battery, and a GTI connected to the same circuit will trick the GTI into firing up and a test of simple electronics on that circuit was successful. What concerns me (so far):