Going from Grid tied, battery backed PV System to Net Metered battery backed system

[rmk9785e]

I erroneously posted this on a sticky and don't know how to remove it so I'm posting it again. Please accept my apologies for double posting.
I am in need of guidance to help a friend who lives overseas in a country where grid power outages are quite common. All systems run on 220V AC. He has had a battery backed 8kW PV system with 4 inverters which would switch to backup power when grid supply went down.
Recently, the utility has started offering net metering and he wants to know if it makes sense for him. His vendor has proposed a single SMA10000TL inverter with SMA WebConnect module for net metering setup. He is told that his existing system will work as Backup system (UPS) where the PV will be attached to Grid Tied Inverter.
I'm not sure how it will switch in the existing system as a backup. The single line diagram (attached) they have provided doesn't show any link with the existing inverters and batteries. Is SMA1000TL a hybrid inverter and should the system look something like the second diagram?

[jflorey2]

I'm not sure how it will switch in the existing system as a backup.

You will need a transfer switch. Also note that the solar system will not charge the batteries when power is out; you need a full hybrid system (with charge controller) to do that.

[rmk9785e]

You will need a transfer switch. Also note that the solar system will not charge the batteries when power is out; you need a full hybrid system (with charge controller) to do that.

Thank you. Please point me to a diagram of such a system with 10kW SMA equipment if you know of one. I browsed SMA web site but couldn't find one. They don't seem to take pre-sales calls from end users. SolarEdge is more open to taking such calls which helped me choose their equipment for my home.

[jflorey2]

Thank you. Please point me to a diagram of such a system with 10kW SMA equipment if you know of one. I browsed SMA web site but couldn't find one. They don't seem to take pre-sales calls from end users. SolarEdge is more open to taking such calls which helped me choose their equipment for my home.

Take a look at Sunny Island; that will do what you want. However if you are looking for such a system I'd recommend an Outback Radian system over an SMA system.

Solaredge is another option, although their battery based system is pretty new and requires you to put an optimizer on every single panel (i.e. a lot of work on your roof.)

[max2k]

I erroneously posted this on a sticky and don't know how to remove it so I'm posting it again. Please accept my apologies for double posting.
I am in need of guidance to help a friend who lives overseas in a country where grid power outages are quite common. All systems run on 220V AC. He has had a battery backed 8kW PV system with 4 inverters which would switch to backup power when grid supply went down.
Recently, the utility has started offering net metering and he wants to know if it makes sense for him. His vendor has proposed a single SMA10000TL inverter with SMA WebConnect module for net metering setup. He is told that his existing system will work as Backup system (UPS) where the PV will be attached to Grid Tied Inverter.
I'm not sure how it will switch in the existing system as a backup. The single line diagram (attached) they have provided doesn't show any link with the existing inverters and batteries. Is SMA1000TL a hybrid inverter and should the system look something like the second diagram?

pardon my ignorance- what is wrong with his current system, what is the goal for the change? As drawn it looks like inverter can push out energy excess to the grid otherwise it will go to the house loads. OTOH the single line diagram shows typical grid tied setup where no battery is involved and it works when grid power is reliable but I thought it is not the case here.

[rmk9785e]

pardon my ignorance- what is wrong with his current system, what is the goal for the change? As drawn it looks like inverter can push out energy excess to the grid otherwise it will go to the house loads. OTOH the single line diagram shows typical grid tied setup where no battery is involved and it works when grid power is reliable but I thought it is not the case here.

Let me provide background info. The current 8KW PV system has four inverters that charge the battery bank during the day and support loads in various parts of the home when grid power goes down which is almost a daily routine. The current setup doesn't lower their bills. Now their utility is offering Net-Metering so their vendor has proposed a setup as described with a single line drawing in my initial post. The goal is to lower his high tier costs with a system that will send the surplus power to the utility after charging the batteries. The batteries would still provide energy during outages.
I, too didn't see any batteries in the single-line drawing and want to learn which equipment and setup will meet the stated goal.

[rmk9785e]

UPS.JPGSingle Line new.JPG
The equipment already istalled is the following:
- 32 Candaian Solar 255W panels
- 2 Infini Inverters of 3 KW each.
− 1 Axpert Inverter of 5 KVA.
− 24 Cells of 2V, 1500 AH.
− 8 Batteries of 12 V, 150 AH.
Now he has a Net Metering proposal to replace the inverters with a 10KW InfiniSolar 3 phase inverter backed by 24 batteries (2V 1500 AH). Additionally, it is proposed that the second set of 8 batteries (12V, 150AH) be reused with 2 existing 3KW inverters for emergency backup.

I'm requesting sharing of your thoughts on this design.