Hi All, I have 3 Axperts in parallel for a 3 phase system with Pylontech batteries. As my roof where the solar is situated is full i would like to add micro inverters with their accompanying panels in another location and connect to only the one phase boosting power to that phase.

Is this possible??

 

 

Just now, Monstergrep said:

Is this possible??

Yes, I believe so, you'll have two separate systems that don't interact in any way. BUT I think you would have to connect the micro inverters to the grid side (where the Axperts connect their AC-in terminals). If you don't want to or can't export, and have no loads that aren't on the three Axperts, then you won't have any benefit.

The micro inverters won't work in a black-out, either, if configured as above.

It's possible that you could connect the micro inverters to the output of one of the Axperts, but I would not recommend it and certainly would never try it myself. Others may have different opinions. In particular, when a large load comes off, the resultant surge of power from the micro inverters may confuse the Axpert control system, and could also damage it.

Thanks for the great reply!! I was concerned about the surge if a load comes off but could this be mitigated by using a grid feed limiting device such as the Hoymiles Data Transfer Unit?

2 hours ago, Monstergrep said:

Thanks for the great reply!! I was concerned about the surge if a load comes off but could this be mitigated by using a grid feed limiting device such as the Hoymiles Data Transfer Unit?

I know nothing about such units, but I doubt it.

I should have said that any time that available solar power exceeds the load (that the micro inverters and one Axpert are connected to), then there is going to be trouble. The micro inverters will try and push power into the output of the Axpert, and that very well might not end well. In other words, the problem isn't just for a short time after a load comes off, it's much worse than that.

Thanks for the info. I will have to look for a plan B!!

8 minutes ago, Monstergrep said:

I will have to look for a plan B!!

I think just a separate MPPT solar charger connected directly to the battery would be the go. Or a few smaller ones if the shading is really bad. Make the absorb and float settings for the smaller MPPTs a little lower than the big one. Edit: that will benefit all three phases.

Edited April 27, 20197 yr by Coulomb

HI Coulomb, when I asked the question I also posed it to a local company that supplies this unit and they have come back and said it is possible with the data transfer unit. As I am no expert and I appreciate any advise I can get, I am a bit weary of a retailers advise as they are trying to sell products which are sometimes not correct/fit for purpose. Please could you check out these two docs and let me know what you think? The thinking is that you will not have excess power pushed back into the Axpert as the DTU has grid limiting capability??

Hoymiles-MI-600-EU-Microinverter.pdf FBIADTUEL_28.08.18_REV3.pdf

That all seems a lot of bother and expense. You didn't say if you have loads not on the inverters, which you could offset with power from the micro inverters.

If not, I don't think that the whole idea will work. Sorry if I didn't make that clear.

On 2019/04/30 at 6:35 AM, Monstergrep said:

HI Coulomb, when I asked the question I also posed it to a local company that supplies this unit and they have come back and said it is possible with the data transfer unit. As I am no expert and I appreciate any advise I can get, I am a bit weary of a retailers advise as they are trying to sell products which are sometimes not correct/fit for purpose. Please could you check out these two docs and let me know what you think? The thinking is that you will not have excess power pushed back into the Axpert as the DTU has grid limiting capability??

Hoymiles-MI-600-EU-Microinverter.pdf 468.72 kB · 4 downloads FBIADTUEL_28.08.18_REV3.pdf 326.76 kB · 2 downloads

There is a new zero export system for Hoymiles. It's wired from the consumption meter to the DTU.

The DTU takes an average of about 15 seconds to throttle completely. So there is a chance of some feedback to the Axpert which is not advised.

0FBIAM3RS (2).pdf 0FBIAM1RS (1).pdf 0FBIADTUARG.pdf

thanks for the feedback