GTI with 2 x 5kva Axperts

[Mike]

Was wondering if anyone has tried this out yet?

If not, tomorrow i will go get a Fronius 4.3kw GTI and connect up with 2 x 5kva Axperts and see if i can get a relatively cheap " hybrid" system going...

[Wetkit]

Which side would you like to put the GTI?

Before the Axperts or after the Axperts?

[___]

2 hours ago, Wetkit said:

Which side would you like to put the GTI?

Before the Axperts or after the Axperts?

I would expect the safe way would be to put them before the Axperts. If the Axpert supports either GFPR (I doubt that it does) or grid feedback (I know it does not), you could put them after it.

The only interesting question that remains, is if it would be possible to adjust the Axpert charge current according to how much the GTI produces, that is, to prioritise solar for battery charging. People like jdp might be able to say if the serial protocol allows such adjustment... :-)

[edmundp]

45 minutes ago, plonkster said:

I would expect the safe way would be to put them before the Axperts. If the Axpert supports either GFPR (I doubt that it does) or grid feedback (I know it does not), you could put them after it.

The only interesting question that remains, is if it would be possible to adjust the Axpert charge current according to how much the GTI produces, that is, to prioritise solar for battery charging. People like jdp might be able to say if the serial protocol allows such adjustment... :-)

It actually does. Would take some clever planning though as the Axpert comms is horribly slow.

[Guest]

I actually have a design for this.  And I did post it here.

Not sure if it will work. It should.

This wont work as all the power goes via the 3KW infini

 

 

[___]

1 hour ago, edmundp said:

It actually does. Would take some clever planning though as the Axpert comms is horribly slow.

That would be fine. It's probably not going to matter if it takes a few seconds or even a minute to respond. The objective would simply be to reduce charge current to a smaller value when there is little or no sunlight, to avoid charging the batteries from the grid. A more complex requirement might be that you want to charge from the grid until Bulk is over and then prioritise solar for float charging, or you might even have a safety function built in (Victron Hub-1 assistant has this) that goes into maintenance mode if there is no sun for several days. It can all be done in software as long as an electronic dial can be turned :-)

[Guest]

Plonky why would you want to do that ? Friend of mine has 3 Axperts and another charge controller all going to the same bank as he has too many panels for the 3 Axpert inverters . Even the Ausie dudes have multiple charge controllers going to the same bank. so why can you not have 3 inverters going to the same bank ?

[Mike]

So i went to town to collect the GTI only to hear it arrives from Jhb on Monday........fackitt.  my thoughts were to put the GTI before for the net metering component with 10 x 300w pv, and then put 6 x 300 on each Axpert to the battery bank. set them for solar charge only, as i am switching on a 2kw wind turbine with its controller onto the same battery bank, that should allow for full charge all the time and then to send the dump load to my geysers element instead of the dump load unit.....gotta play and gotta learn and most likely ask a moerse lot of questions

[___]

1 hour ago, jdp said:

Plonky why would you want to do that ? Friend of mine has 3 Axperts and another charge controller all going to the same bank as he has too many panels for the 3 Axpert inverters . Even the Ausie dudes have multiple charge controllers going to the same bank. so why can you not have 3 inverters going to the same bank ?

I think you misunderstand the situation here. There is of course no problem having multiple charge sources going to the same bank. But the Fronius doesn't charge batteries (like the Infini?), it's pure GTI. So in the situation where you are using the Axpert's AC charger -- which is common for AC-coupled systems -- you may prefer to prioritise solar power over grid power, that is to say, you deliberately lower the charge current to what the GTI provides on your input side to avoid using grid power. So I was merely wondering if it would be possible to use the Fronius/Axpert combo in such an AC-coupled scenario :-)

Edited: And I was wondering that because there is generally three things you want to do when you AC-couple PV with backup, 1) You want to tie with the output, so that your GTI continues to work when the grid is out, for this you need GFPR, 2) you want the backup inverter to allow feedback to the grid when the grid is up, 3) you want to prioritise solar, if you're charging the batteries. Since 1 and 2 is already ruled out for the Axpert, I was wondering if 3 is possible. So 1 out of 3 for this combo :-)

[Guest]

Aaa OK. But the way I have it then in my diagram will work if I use a Infini? You charge the batteries and if they are full the leftover power goes to the grid from the Infini. And then when AICC switches both Axperts to grid mode at around 5pm then I use what went to the grid again.

[___]

56 minutes ago, jdp said:

Aaa OK. But the way I have it then in my diagram will work if I use a Infini? You charge the batteries and if they are full the leftover power goes to the grid from the Infini. And then when AICC switches both Axperts to grid mode at around 5pm then I use what went to the grid again.

I don't see why not :-)

[SilverNodashi]

I'm quite curious, why use a GTI with the Axpert? Why not rather just use a GTI on it's own?

[Guest]

Because you do not get a 8Kw GTI on its own to run my house. I run everything on solar, not just the lights. If they made a 8Kw GTI I would get it yesterday.