The Quattro advertises a 100 amp transfer switch. However, if using this transfer switch while the consumption is over the capacity of the Quattro (but still well under 100A) overload issues are very likely to occur because the inverter is used during the transfer. Using the inverter during the transfer is fine when the consumption is less than the Quattro can handle. Effectively the transfer switch is not functional in some conditions despite being well under the rated and advertised 100A load.
- Disable inverters (switch to charger only?) on mains loss if the consumption of any phase is over the current overload warning limit (assuming it changes with temperature). Re-enable inverters when power has returned for ESS functionality. This could possibly be implemented in Quattro firmware.
- Wait for a few minutes and reset system in the event of an overload warning on mains failure. This could be implemented on a GX device with automatic generator start set up to start on overload warning/alarm. Right now this function is useless for mains failure as the inverters have shut down due to overload by the time the generator has started and do not automatically reset.
Both of these options would have at least a short time when there is no power to the system. To me that is much more acceptable than manually resetting one or more inverters, especially for an unattended site.
I know that some people will probably consider that this is an issue of system design, and that the critical loads should not exceed the inverter capacity. However considering that the inverter could overload at different points depending on temperature, battery state, etc. it seems like this is a legitimate problem. Also consider that the transfer switch is rated for 100A which currently no inverter provides. And there are some use cases where it makes sense to run all of the power through the main output of the inverter and use generator to supply during times of especially high load.
Other possible solutions and suggestions are welcome!
- Mentioned in comments here
- And @Matthias Lange - DE mentions the problem in his answer here