Adding grid tie inverter to existing off grid (Axpert hybrid inverter) system

[timselectric]

That's great news - I will need a 24v charger because I don't have room on my roof to keep the existing panels ?
I'm gonna have to figure out how to arrange my eighteen 450w panels, I was planning on 2 strings of 9 panels, but I guess with 2 Growatt inverters I would need 4 strings, right?

You can split them up. Some on each inverter.
How, would depend on the VOC of the panels.

 

[Ampster]

It would be tough charging an EV with only 3kw

It would also be slow. I think the slowest my EVs will charge at is 6 Amps which is about 1.5 kWs. It all depends on the make and model of EV you purchase.

 

[Mikenr]

You can split them up. Some on each inverter.
How, would depend on the VOC of the panels.

Any idea of the standby consumption of the Growatts? or would they just power down when the sun goes? if they are not connected to a battery - I need to educate myself re connecting them to the output of my Axpert inverter . . .

 

[timselectric]

Any idea of the standby consumption of the Growatts? or would they just power down when the sun goes? if they are not connected to a battery - I need to educate myself re connecting them to the output of my Axpert inverter . . .

Growatt claims 60w.
Mine are using 54w, so pretty close. You could avoid it at night with a separate transfer switch. An automatic one would take care of it for you.
Or a simple setup with two relays and photocell.

 

[Mikenr]

Growatt claims 60w.
Mine are using 54w, so pretty close. You could avoid it at night with a separate transfer switch. An automatic one would take care of it for you.
Or a simple setup with two relays and photocell.

Great! Thank you SO much ???

 

[Mikenr]

Any idea of the standby consumption of the Growatts? or would they just power down when the sun goes? if they are not connected to a battery - I need to educate myself re connecting them to the output of my Axpert inverter . . .

Can I just connect the outputs of the 2 Growatts (I understand they need to be configured to work in parallel) to the output of my Axpert?

 

[timselectric]

Can I just connect the outputs of the 2 Growatts (I understand they need to be configured to work in parallel) to the output of my Axpert?

No
That would make magic smoke.
Once the magic smoke gets out, you can't get it back in.

 

[timselectric]

The smaller inverter would lose that battle.

 

[Mikenr]

No
That would make magic smoke.
Once the magic smoke gets out, you can't get it back in.

Hahaha - hmmm I don't like the idea of magic smoke ? can you point me in the direction of where I can learn how to integrate the Growatts with the Axpert? Thank you again! ??

 

[timselectric]

Hahaha - hmmm I don't like the idea of magic smoke ? can you point me in the direction of where I can learn how to integrate the Growatts with the Axpert? Thank you again! ??

Output of the Axpert to the AC input of the Growatt's.
Nothing very complicated.
I'll also link the manual, shortly.

 

[timselectric]

.

https://signaturesolar.com/content/documents/GROWATT/1519013-manual.pdf

 

[Mikenr]

Output of the Axpert to the AC input of the Growatt's.
Nothing very complicated.
I'll also link the manual, shortly.

Then if the Growatts were set to be disconnected when the sun goes down it would need to be a 'divert' from the output of the Axpert then go 'directly' to the house - right?

 

[timselectric]

Then if the Growatts were set to be disconnected when the sun goes down it would need to be a 'divert' from the output of the Axpert then go 'directly' to the house - right?

Correct

 

[Mikenr]

So you are totally off-grid with only a 3kw inverter?
Impressive...

I started out with a 100w water turbine directly wired to lights and an amplifier which when the music was turned up the lights would dim to the beat ? that was in about 2004/5

 

[Mikenr]

.

https://signaturesolar.com/content/documents/GROWATT/1519013-manual.pdf

I have started reading it, thank you - I have seen this 'Parallel operation up to 6 unit (only with battery connected)' do you know if that applies to having 2 connected - I guess it would . . . ?

 

[timselectric]

I have started reading it, thank you - I have seen this 'Parallel operation up to 6 unit (only with battery connected)' do you know if that applies to having 2 connected - I guess it would . . . ?

Crap, I forgot about that little fact.
Any small 48v references will do. They just need to see the same voltage at the battery terminals.
But, it does make it more complicated.
And I don't think stacking them in series would give you enough output. (Maybe 7kw)

 

[Mikenr]

Crap, I forgot about that little fact.
Any small 48v references will do. They just need to see the same voltage at the battery terminals.
But, it does make it more complicated.
And I don't think stacking them in series would give you enough output. (Maybe 7kw)

Hmmm damn - I thought I was getting close to a solution ??

Is it not possible to use a (or 2 in parallel as my system is single phase) grid tie inverters set up as zero feed? My only concern is that although the energy meter is there to stop feed-in I have seen them feed a small amount to the grid - which I don't know if it would be enough to make my Axpert produce 'magic smoke' ?

 

[timselectric]

Hmmm damn - I thought I was getting close to a solution ??

Is it not possible to use a (or 2 in parallel as my system is single phase) grid tie inverters set up as zero feed? My only concern is that although the energy meter is there to stop feed-in I have seen them feed a small amount to the grid - which I don't know if it would be enough to make my Axpert produce 'magic smoke' ?

An off grid inverter (your Axpert) isn't designed to handle power coming in on its output.
And grid-tied inverters produce their maximum output regardless of the load. (Without external control)
They require a buffer to take the excess power.

 

[Mikenr]

An off grid inverter (your Axpert) isn't designed to handle power coming in on its output.
And grid-tied inverters produce their maximum output regardless of the load. (Without external control)
They require a buffer to take the excess power.

I understand that, but when configured for zero feed-in then the output from the grid tie must be variable, no?

In the end I think I'm going to go for a second Axpert the same as I have, then at least I will have 6kW to play with until I am ready to upgrade to a 48v system - the only problem I have at the moment is that my granny charger for the car doesn't like the Axpert power ? it doesn't see the earth, neither does my socket tester although all the earth wires are connected and the earthing rod is about a meter into the ground in a damp place ?

I read somewhere that the Axpert I have has an odd way of producing 220v but I don't remember how or why ? they why is because it's a cheap inverter I guess ? More figuring out still to be done ?

 

[timselectric]

I understand that, but when configured for zero feed-in then the output from the grid tie must be variable, no?

In the end I think I'm going to go for a second Axpert the same as I have, then at least I will have 6kW to play with until I am ready to upgrade to a 48v system - the only problem I have at the moment is that my granny charger for the car doesn't like the Axpert power ? it doesn't see the earth, neither does my socket tester although all the earth wires are connected and the earthing rod is about a meter into the ground in a damp place ?

I read somewhere that the Axpert I have has an odd way of producing 220v but I don't remember how or why ? they why is because it's a cheap inverter I guess ? More figuring out still to be done ?

Are the Axpert inverters stackable?
Or will you have to have separated loads?
I'm guessing it's the latter.