I recently bought 3 Axpert inverters for the purposes of running on a 3 phase supply.

When I queried with the supplier whether they were able to be paralleled, they said yes, but I need to purchase the parallel kit (fair enough).

On opening the inverters, it appears that there is already a parallel card installed. It is identical (vga type connections, etc) to the additional cards I bought but missing 2 chips. I initially thought it might be some sort of dummy board, but I've found no information on this, only completely blank boards. The inverter also came with all the parallel cables. Also seems like there is some "glue" of sorts keeping the connections there.

Sorry didn't take pics

Short of just testing them as is to see if they work in parallel (and possibly have to take off again, to change boards), is there another way I can confirm what is there?

Here is a pic that looks like the additional board I have bought.

I've circled the chips that I refer to as being "missing" in the original board

 

Hi @DaveP,

Welcome to the forum...

With 3 Axperts & 3 phase requirement, you would not need any parallel kit/cables. Refer to the installation manual. The setting per Axpert would be either Single, Parallel, 3P1, 3P2 or 3P3.

Single = for standard single phase setup with 1 inverter...that's the default.

Parallel = for single phase with multiple Axperts. Up to six for the older models, up to 9 for the newer models.

3P1 = is for the 1st Axpert of a 3 phase setup.

3P2 = is for the 2nd Axpert of a 3 phase setup.

3P3 = is for the 3rd Axpert of a 3 phase setup.

On top of that, you can parallel Axperts in any or all of the phases.

e.g. if you had 4 Axperts, you can have 2 of them on Phase 1 (to provide more oompf for the house's requirements), and 1 on Ph2 & Ph3, to power up any 3 ph machine e.g. borehole pump.

Alternatively, you can split the large house into 2 (or even 3) sections, each running of a different phase, to balance the loads on each Axpert, keeping below the 5kVA/kW(depending on PF) for each.

36 minutes ago, Sidewinder said:

Hi @DaveP,

Welcome to the forum...

With 3 Axperts & 3 phase requirement, you would not need any parallel kit/cables. Refer to the installation manual. The setting per Axpert would be either Single, Parallel, 3P1, 3P2 or 3P3.

Single = for standard single phase setup with 1 inverter...that's the default.

Parallel = for single phase with multiple Axperts. Up to six for the older models, up to 9 for the newer models.

3P1 = is for the 1st Axpert of a 3 phase setup.

3P2 = is for the 2nd Axpert of a 3 phase setup.

3P3 = is for the 3rd Axpert of a 3 phase setup.

On top of that, you can parallel Axperts in any or all of the phases.

e.g. if you had 4 Axperts, you can have 2 of them on Phase 1 (to provide more oompf for the house's requirements), and 1 on Ph2 & Ph3, to power up any 3 ph machine e.g. borehole pump.

Alternatively, you can split the large house into 2 (or even 3) sections, each running of a different phase, to balance the loads on each Axpert, keeping below the 5kVA/kW(depending on PF) for each.

Thanks for the reply. 

The documentation shows otherwise (pic below).

Keeping in mind that the inverters are running off the same battery bank

Ah ha...see, I stand to be corrected. Thanks for that. At least you do not need the current sharing cables.

In case your system does not come up the first time, don't panic, mine took a few resets, with frantic panic inspections of double checking the cable orientation the first time, but mine is just standard parallel. Hopefully yours is a breeze.

Regarding your original question, i remember i had to remove what you describe as a dummy board as well, but is was 3 years ago, and can't really remember is those 2 chips were missing or the rest of the board populated. I seem to think that the cables were plugged in on the dummy board.

15 hours ago, DaveP said:

On opening the inverters, it appears that there is already a parallel card installed. It is identical (vga type connections, etc) to the additional cards I bought but missing 2 chips.

That's pretty weird. As far as I know, those are essential chips, possibly isolating CAN bus drivers. I suppose it's possible that they have been replaced with surface mount chips that are now on the bottom of the board (opposite side to the through-hole components).

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I initially thought it might be some sort of dummy board,

No, the dummy boards are really simple: paper PCB, no tracks, just 14 pads and holes to mount the socket for the cable (so it doesn't flop around and cause trouble). 

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The inverter also came with all the parallel cables.

That suggests that it's ready to use. There are some models that come with the paralleling boards installed. 

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Also seems like there is some "glue" of sorts keeping the connections there.

I don't follow: keep what connections where?

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Short of just testing them as is to see if they work in parallel (and possibly have to take off again, to change boards), is there another way I can confirm what is there?

I would take out one of the paralleling boards, and see if there are two 8-pin surface mount devices under the board. If so, go ahead and use the already installed boards. You could also check the part numbers for the boards; they should differ only in the last group ending in "G" (Generation? Like a version number for the hardware.) For example, on the internet I see boards with numbers like 16-500243-00G; if your new cards are like this but the existing ones are e.g. 16-500243-02G, then they're the same thing with a different generation number.

Edit: also, when you change setting 28 to 3P1 etc, of course initially you will have AC-in and AC-out isolated. So you could leave the AC-in, AC-out, and PV disconnected initially. If you get one master and two slaves, and none of the slaves shows NE (NEw) intermittently, that's actually a sign that the parallel communications have passed a lot of tests, and you can be pretty confident about going ahead and connecting the rest of it.

Edited March 10, 20205 yr by Coulomb

Some feedback, so we connected up the inverters (with original cards) and they run in parallel mode without any issues.

Thanks for the help