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

timselectric · Nov 23, 2022

Mikenr said:
it doesn't see the earth,

It won't, unless there's a N/G bond.
But I would not recommend that, without checking with the manufacturer. Some inverters can't handle this. I have fried a few inverters, by assuming that it would be ok to bond them.
(Years ago before I knew any better)

Mikenr · Nov 23, 2022

Some of the Axperts can be connected in parallel - I am have emailed support to see if mine is, as it's not clear from what I have read on various pages . . .

Mikenr · Nov 24, 2022

timselectric said:
It won't, unless there's a N/G bond.
But I would not recommend that, without checking with the manufacturer. Some inverters can't handle this. I have fried a few inverters, by assuming that it would be ok to bond them.
(Years ago before I knew any better)

Thank you again Tim! I was considering connecting the negative to ground, but was very wary of doing so...

Finally I have been able to get through to 'Master Power' the branded name of the Axpert inverter I have - unfortunately I can't parallel my inverter

So the way I see it is that I have 2 options - 1. is to use a Victron Orion Tr24-48 to give a 48v feed to a pair of Growatt inverters and the other is to try and connect my two 24v battery banks in series and buy a larger 48v hybrid inverter - The battery banks are of similar capacity (one being built from 18650 cells and the other LEV50s, but no way identical) the BMSs are generic ANT ones from China and so far I have been unable to find out if I can connect them in series . . .

So that's where I'm at

timselectric · Nov 25, 2022

Mikenr said:
Thank you again Tim! I was considering connecting the negative to ground, but was very wary of doing so...

Finally I have been able to get through to 'Master Power' the branded name of the Axpert inverter I have - unfortunately I can't parallel my inverter

So the way I see it is that I have 2 options - 1. is to use a Victron Orion Tr24-48 to give a 48v feed to a pair of Growatt inverters and the other is to try and connect my two 24v battery banks in series and buy a larger 48v hybrid inverter - The battery banks are of similar capacity (one being built from 18650 cells and the other LEV50s, but no way identical) the BMSs are generic ANT ones from China and so far I have been unable to find out if I can connect them in series . . .

So that's where I'm at

Putting different types of batteries in series is not something that I would recommend. I don't even recommend putting same type of batteries in series, if they have BMS's. It just adds maintenance to a maintenance free system.
Parallel is fine as long as the charging profiles are similar.
The Orion would work. You just need to set it's output voltage above the charging voltage settings for the Growatt's.

Mikenr · Nov 25, 2022

timselectric said:
Putting different types of batteries in series is not something that I would recommend. I don't even recommend putting same type of batteries in series, if they have BMS's. It just adds maintenance to a maintenance free system.
Parallel is fine as long as the charging profiles are similar.
The Orion would work. You just need to set it's output voltage above the charging voltage settings for the Growatt's.

Hmmm that's what I thought re putting the batteries in series . . . ?

One last thing that I have thought of - if I am switching the growatts on and off with a changeover type switch, which I would want to also be disconnecting the Orion to avoid unnecessary self consumption overnight, will the Growatts start up again when the changeover switch gives them power again? I don't want to have to go and switch them on 'manually' every morning - plus I want the system to autonomous when I am away and be able to come back to a nice warm house and a tank of hot water ?

One other important point - do you know if the Growatts will work OK to charge my car?

Once again thank you SO much ??

timselectric · Nov 25, 2022

If you leave the inverter power switch on. And just disconnect the power sources. When you reconnect them, it will start up again.
As far as EV charging, it should work fine.
Most charging stations require a N/G bond to work.
This may need to be addressed. The Growatt does it automatically (non US version) in battery mode. But, you will be using them in SUB mode.
Does the Axpert bond N/G?
If not,
Is it ok with external bonding?

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

timselectric

If I can do it, you can do it.

Mikenr

New Member

Mikenr

New Member

timselectric

If I can do it, you can do it.

Mikenr

New Member

timselectric

If I can do it, you can do it.

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