Quattro: Second input is not supported correctly

Q&A and troubleshooting
, , ,
1

System:
Quattro as ESS
Generator connected to AC in1
Grid connected to AC in2
Standard loads connected to AC in2
Fronius Symo connected to AC in2
Critical loads connected to AC out
No DC MPPTs

When the generator runs under load once a month for testing, the Quattro switches the power to the critical loads. The grid continues to supply the normal loads. The current generated by the Fronius Symo (AC in2) charges the batteries and feeds into the grid if necessary.
This is how it should be.

However, when the batteries are full, the Fronius Symo is throttled down, even though it is connected to the grid input AC in2 rather than the generator input AC in1. If the control is switched off by disabeling “sunspec,” the battery voltage rises above the set value until the BMS shuts down.

For a Multi with only one input, this behavior would be correct.
DC MPPTs, if present, would also have to be throttled down.

With a Quattro, however, the system does not take into account that it has two separate inputs and that these can be configured differently.

2

An interesting situation. Ithink the geneal assumption (in controls) in running is if the generator is running and connected there is no grid. But this is not the case with a maintenance run.

Do you have a grid meter before your loads and fronius? And is grid feed in allowed or not allowed?

How long is it running for? Usually a for testing scenario is warm up, short run, cool down. Not usually a full battery charge type thing. So possibly a 15 or 20 minute run.

3

Yes, grid feed is allowed and works fine when the batteries are’n full yet. (when there is more solar power than the Quattro can put into the batteries)
No, there is only one grid meter at the input of the grid. The normal loads an the critical loads are monitored by the Quattro, the Symo tells his power by “sunspec” or api.

4

Yes, you are right. Max. half an hour, but when the batteries are already full when starting the test scenario, the Symo is throttled down.