Sunnyboy Island or Outback GVFX ?

[garybeck]

I have a customer who already has a grid-tie system and he wants to add batteries. He might also want to add more modules. We are exploring the options. He has a sunny boy inverter so the options are

1) Add a Sunny Island and batteries, no modules.
2) Add a Sunny Island, batteries, another Sunny Boy, and modules.
3) Leave the existing array alone and add a 2nd array with batteries and Outback GVFX (and Outback charge controller)

I was talking to a friend who works at another solar company and he said the Sunny Island systems get complicated especially when there are two inverters (may need a 2nd Sunny Island too) and the Outback system is simpler.

Anyone have experience with both types and any comments on which you prefer and why?

thanks

[inetdog]

I have a customer who already has a grid-tie system and he wants to add batteries. He might also want to add more modules. We are exploring the options. He has a sunny boy inverter so the options are

1) Add a Sunny Island and batteries, no modules.
2) Add a Sunny Island, batteries, another Sunny Boy, and modules.
3) Leave the existing array alone and add a 2nd array with batteries and Outback GVFX (and Outback charge controller)

I was talking to a friend who works at another solar company and he said the Sunny Island systems get complicated especially when there are two inverters (may need a 2nd Sunny Island too) and the Outback system is simpler.

Anyone have experience with both types and any comments on which you prefer and why?

thanks

The main question I have for you about option 3 is whether you/he are willing to give up the availability of the current wattage for backup just to get a simpler system?
The Outback may be simpler, but probably will not cooperate with the Sunny Boy. If the second system (inverter, not batteries) would be big enough for estimated loads while on backup, then that is not an issue, except for the loss of panel output.
Some have suggested a manual panel switch that transfers some or all GTI panels over to the battery system during a grid outage.

[billvon]

1) Add a Sunny Island and batteries, no modules.
2) Add a Sunny Island, batteries, another Sunny Boy, and modules.
3) Leave the existing array alone and add a 2nd array with batteries and Outback GVFX (and Outback charge controller)

Option 4 - leave the current array alone, get a Xantrex XW-MPPT-80, batteries and an Outback GVFX.

Option 5 - go with option 3 and then use the current GTI system in AC-linked mode. (see Outback app note on how to do that.)

[garybeck]

The main question I have for you about option 3 is whether you/he are willing to give up the availability of the current wattage for backup just to get a simpler system?
The Outback may be simpler, but probably will not cooperate with the Sunny Boy. If the second system (inverter, not batteries) would be big enough for estimated loads while on backup, then that is not an issue, except for the loss of panel output.
Some have suggested a manual panel switch that transfers some or all GTI panels over to the battery system during a grid outage.

yes with option #3 I have discussed with him, the original array and Sunny Boy inverter will be down and useless when utility power goes out. we designed the 2nd array which is 2.1Kw, to meet his needs when utility power is out.

Yes I would not try to connect an Outback to the Sunny Boy or sunny Island. If we do #3, they would essentially be separate systems, but on the same net meter.

I'm interested in this "panel switch". what's that?

[garybeck]

Option 4 - leave the current array alone, get a Xantrex XW-MPPT-80, batteries and an Outback GVFX.

Option 5 - go with option 3 and then use the current GTI system in AC-linked mode. (see Outback app note on how to do that.)

What app note? sounds interesting.

[Naptown]

The simplest thing would be to use the sunny islands. It will require 2 as they only output 120V. And you can most likely use the existing array.
Xantrex and Magnum also have systems that can be AC coupled and output 240V.
Depending on the system you will most likely need a diversion controller and load(s) to keep the batteries from overcharging.
You will also either have to install a sub panel to isolate the critical battery circuits or a manual transfer switch rated for the entire house as if you feed the entire panel you will backfeed to the grid on battery power.

[garybeck]

The simplest thing would be to use the sunny islands. It will require 2 as they only output 120V. And you can most likely use the existing array.
Xantrex and Magnum also have systems that can be AC coupled and output 240V.
Depending on the system you will most likely need a diversion controller and load(s) to keep the batteries from overcharging.
You will also either have to install a sub panel to isolate the critical battery circuits or a manual transfer switch rated for the entire house as if you feed the entire panel you will backfeed to the grid on battery power.

thanks for your input. we do already have a sub panel for the critical loads. They are all 120V except one, and we were going to use a transformer for it.

Since we have the sub panel, we shouldn't need a transfer switch. thanks