Howdy folks, I was wondering if someone here could perhaps help me better understand how the Axpert IV V 5,6kW parallel function works.

I have a site that is running on a 3-by-3 grid of 9 inverters that are all connected in parallel. (I know, not my call so just trying to work with what we got here) So I have been noticing that unless they are turned on in a specific order, I will get an F80 if they are all turned on at once. With loads of fiddling, a specific order has been found that doesn't cause F80. However, now only some of them are showing the parallel icon shown below:

So now, I only have 3 inverters showing the parallel icon and for some reason those 3 aren't switching from standby mode (The ring doesn't light up). The rest start up and allocate phases just fine but they do not show the parallel icon. I am not familiar enough with how these parallel and communicate, is there someone here that could shed a little light on this for me?

Check setting 28; these would all need to be set to PAL.

Though a 3x3 array might actually be 3-phase; if so sets of three would be set to 3P1, 3P2, and 3P3. You only have current sharing cables between inverters on the same phase.

Note that setting 28 can't be changed when the inverters are switched on. But you can read the setting at any time.

Nine paralleled inverters would be a tricky installation. Good luck.

3 hours ago, Psy said:

Axpert IV V 5,6kW

I note that Axpert VM IVs can't be paralleled at all. Axpert MKS IV are the ones that can be paralleled.

Hopefully that isn't the problem.

Thanks @Coulomb, your feedback is always appreciated! Ok, so the ones installed have a parallel board installed for this feature, as shown below:  

I also found out the system in grid tied, so no batteries just solar panels feeding the loads with grid backup. So it seems like the units only give the F80 error only occurs when the grid trips. I am assuming that the load is a little too big for only PV, so batteries are needed. I just don't know why the system went from perfect sync to now only some showing the coms icon, is it possible that the parallel boards were somehow damaged? Why would grid dropping cause an F80?

2 hours ago, Psy said:

is it possible that the parallel boards were somehow damaged?

Yes, I think that they are a bit vulnerable to damage, due to the long cables connected to them (e.g. in lightning situations). There are of course longer cables on PV and AC in/out ports, but those connect to power electronics; the parallel boards contain dainty SMD parts.

3 hours ago, Psy said:

Why would grid dropping cause an F80?

Good question. I just spent an hour looking at what causes fault code 80. There are three cases:

* We're a "new" (not yet master or slave) and we detect CAN bus comms timeout

* We're a slave, and we detect CAN bus comms timeout

* We're a master, and a slave has just disappeared, and that slave isn't in fault mode or shutdown mode.

None of these seems to have much to do with the grid dropping out, unless the loss of grid (with typically large inductive loads) causes enough of a transient that it temporarily (or permanently?) frazzles the CAN bus circuitry. That seems unlikely. So sorry: I don't know.

Thanks a mill for the clarification, that makes a little more sense. As it stands the system is setup without batteries but all the DC connections have already been wired to a DC bar for future battery connection. Perhaps this is causing the system to detect a battery but no coms... So when the grid drops it tries to connect to a battery bank that isn't there confusing the hell out of them?

This sounds like a project that will tickle the fancy of Mr @Steve87 ! 

Hi @PsyI have a long history of parallel ops & Voltronics. You can run batteryless with these but only with a single stand alone unit. Running batteryless in parallel is a recipe for all sorts of Faults. 

So getting back to your installation. Setting up for 3 phase ops requires as said above by the Grand Master @Coulomb3P1, 3P2 & 3P3. 

each of these machines will have a phase. When you start to add parallel sets in the same phase you need to add the current Sharing cables for each in the same phase. 

it's becomes a spaghetti of Comms cables & current sharing cables, but I would not run these batteryless its not going to be a viable solution. 

That was my thinking as well. I think having 50kW worth of batteries available would make this viable but just adding like 10kW isn't really going to help much, no batteries is apparently even worse... I am advising they either buy loads of batteries or step up to 3 phase inverters. They are talking about replacing the 5,6kW inverters with 2 MAX-Es per phase but I assume they're just going to have the same issue until a battery bank is added (Sounds like they need a min of 15kW per phase)

Better still install the new generation Infinisolar inverter. It can also run batteryless & is 15kW 3¢.