I'm absolutely amazed at how well Sunny Island inverters work.

[z80]

We don't keep the Sunny Islands connected for personal application reasons. The primary concern is that I don't want a lightening strike to take out my ridiculously expensive inverters and battery management system, so with that in mind, we keep them isolated from all four lines (L1, L2, Neutral, Ground) until the system is needed. The second reason is that the Sunny Islands are designed in such a way that you either need a "critical loads panel", which doesn't power the whole house, or a very expensive transfer switch. Neither of these was appealing to me as both added significant costs and rewiring work as well as more wall space for the extra hardware.

When we go into off-grid mode, we have full power to the entire home. Nothing changes other than a 3 minute blackout while the system is manually turned on. The outputs of the Sunny Islands feed right back through the main breaker panel. In fact, I usually need to turn off one of the solar arrays because the Sunny Boys make a lot more power than we actually use during most of the year. Last time we used the system, the solar array was throttled down to 61.8hz, so only 0.2hz from tripping out. I had to turn on fans and the television just to draw a bit more juice.

I do it differently...I run off grid all the time...with the grid connected to the generator input of the Sunny Island.

So there is no dead time...in fact we often see neighbours dark and only then realize grid has gone down.

Grid charges the batteries only when all else has failed...no sun..batteries down...evening.

We also have cheaper power tarriffs so I installed a timer which further limits when the errr..."generator" can supply power.

I now have 5 sunny islands in two locations, guy who sold me 3 of them had them ina 3 phase setup....somebody convinced him to toss it out and buy two Powerwalls......FAIL

[Salts]

I'm curious why you don't have the Sunny Islands setup so that they are running in grid-tied mode too? I am currently looking at adding battery backup to my system (Sunny Boy 4000TL with 4.2kW of Sunpower X21 panels), and the configuration I am planning is also using SMA equipment: an SMA ABU, an SMA Sunny Boy Storage 6.0 and a BYD Battery Box. I like the ABU because of the way it governs the system in grid-tied mode, so as solar power output is going down at the end of the day it pumps battery power into the grid (up to the legal maximum), maximizing return from the time of use rate structure. The ABU also has an automatic transfer switch, so utility power down and up events are handled automatically. In off-grid mode battery and panel output are not throttled (except as needed to avoid overcharging batteries), so full power is available.

We don't keep the Sunny Islands connected for personal application reasons. The primary concern is that I don't want a lightening strike to take out my ridiculously expensive inverters and battery management system, so with that in mind, we keep them isolated from all four lines (L1, L2, Neutral, Ground) until the system is needed. The second reason is that the Sunny Islands are designed in such a way that you either need a "critical loads panel", which doesn't power the whole house, or a very expensive transfer switch. Neither of these was appealing to me as both added significant costs and rewiring work as well as more wall space for the extra hardware.

When we go into off-grid mode, we have full power to the entire home. Nothing changes other than a 3 minute blackout while the system is manually turned on. The outputs of the Sunny Islands feed right back through the main breaker panel. In fact, I usually need to turn off one of the solar arrays because the Sunny Boys make a lot more power than we actually use during most of the year. Last time we used the system, the solar array was throttled down to 61.8hz, so only 0.2hz from tripping out. I had to turn on fans and the television just to draw a bit more juice.

[Rimcanyon]

I'm curious why you don't have the Sunny Islands setup so that they are running in grid-tied mode too? I am currently looking at adding battery backup to my system (Sunny Boy 4000TL with 4.2kW of Sunpower X21 panels), and the configuration I am planning is also using SMA equipment: an SMA ABU, an SMA Sunny Boy Storage 6.0 and a BYD Battery Box. I like the ABU because of the way it governs the system in grid-tied mode, so as solar power output is going down at the end of the day it pumps battery power into the grid (up to the legal maximum), maximizing return from the time of use rate structure. The ABU also has an automatic transfer switch, so utility power down and up events are handled automatically. In off-grid mode battery and panel output are not throttled (except as needed to avoid overcharging batteries), so full power is available.

[Ampster]

Yes that is exactly what i mean by modulation.

[Salts]

Thanks that was helpful. I guess there is no modulation, just on or off for the GT inverters.
The reason I am asking is I am getting ready to AC couple my Solar Edge GT inverter to my Outback Skybox and was trying to anticipate any issues when off the grid. I currently have four Enphase IQ-7s AC coupled and they do modulate depending on the load and the batteries thirst for energy.

I am expecting the SolarEdge will also modulate since they are fairly recent firmware. We are moving into the time of year that we will have expected power outages and i have a new pack. I am expecting that it will get me through a couple days with no sun, but I want to have all the available solar available for charging if there is sun.

I'm not entirely sure what you mean by "modulation". But if I get you correctly, then YES there IS modulation. When the batteries start to approach full charge, the Sunny Islands raise the frequency to 61.1 hz. This causes the Sunny Boy GT inverters to reduce they're output power by 10%. For each 0.1hz above 61hz, the GT inverters will reduce by another 10%. At 62hz, they trip on over-frequency. This is FSPC (Frequency Shift Power Control) that is employed by the Sunny Islands to throttle (modulate ?) the GT output power.

For example, when my batteries were at 98-99% SOC, and my home was pulling about 700 to 800 watts, the Sunny Island inverters were holding the frequency at around 61.8 to 61.9 hz... this caused the GT inverter, under full sun with 5.4kw of panels, to only produce about 700 to 800 watts.

There's a limit to FSPC.. Its like trying to make your car go 0.5 miles per hour... its difficult to do that.

[Ampster]

Thanks that was helpful. I guess there is no modulation, just on or off for the GT inverters.
The reason I am asking is I am getting ready to AC couple my Solar Edge GT inverter to my Outback Skybox and was trying to anticipate any issues when off the grid. I currently have four Enphase IQ-7s AC coupled and they do modulate depending on the load and the batteries thirst for energy.

I am expecting the SolarEdge will also modulate since they are fairly recent firmware. We are moving into the time of year that we will have expected power outages and i have a new pack. I am expecting that it will get me through a couple days with no sun, but I want to have all the available solar available for charging if there is sun.

[Salts]

When both GT inverters are connected do they modulate or cycle on and off? I wonder if it is headroom on your batteries? For example, if you started out the day with a lower SOC on your batteries if the GT inverters could run full warp? Or are you approaching the full charging capacity of your pack?

My pack is a 480ah Lithium (Chevy BOLT cells) configured 14s8p (or is it 8p14s?) and it can take a 1C charge rate, so theoretically, they could take everything both GT inverters can produce and more. Problem is, that would generate a lot of heat... heat bad. very bad.

When the pack is full, the Sunny Island's start to throttle the active SunnyBoy with FSPC.. and my house only draws about 500 to 800 watts most of the time. Even with just one inverter turned on under full sun, the frequency ends up in the 61.8hz to 61.9hz range. Just 0.1 hz higher and and the inverter will trip out. Sometimes I have to start turning stuff on just to prevent it.

This is only an issue on cool summer days.. in the winter, I just plug in a space heater. The Sunny Islands have a load dump option just for this purpose, I should probably hook it up.

[Ampster]

When both GT inverters are connected do they modulate or cycle on and off? I wonder if it is headroom on your batteries? For example, if you started out the day with a lower SOC on your batteries if the GT inverters could run full warp? Or are you approaching the full charging capacity of your pack?

[Salts]

If we use the Sunny Island 8.0H we don’t need other controller to regulate PV the balance between the energy feed in and energy used ? Our set up is PV grid tie with 10Kw panel using 2 Sunny Boy Inverter. We want to go off grid. What is the maximum size of the generator that we can connect to a Sunny Island 8.0H ?

Thank you.

The maximum solar energy that can be fed through them isn't as much about the Sunny Island as it is the battery bank. I think the Sunny Islands are limited to 140 amps per 6048, but you'd have to check on the 8.0H... But that's their limit, not your system limit.. your battery will probably be far more restrictive. For example, I have two Sunny Island inverters (6048) and two Sunny Boy (6kw) grid inverters on a 10.7 kw system. When I go into off grid mode, I turn off one of the Sunny Boy inverters, which cuts my solar array almost exactly in half to around 5.4kw. This limits the power being delivered to the 24.5kw Lithium battery bank. 480 amp hours of battery can only accept about 80 amps of charge before it starts to generate heat, and heat is bad. And lead acid batteries will start to gas if you charge them too fast as well.

Now, that said, if I go off-grid during cloudy dark skies, and if I need more solar power, I just flip the 2nd Sunny Boy on.. Due to the FSPC (Frequency Shift Power Control) which the Sunny Islands use to control the Sunny Boy's (a sort of throttling of their solar output power), there's a lot of over-lap of when I should and shouldn't use the 2nd array. The amount of sunshine and the SOC of the battery bank and our current load useage, all make a difference if I want the engine room to deliver max warp speed.

So really, it depends mostly on your battery bank.

If you have a Sunny Island, a Battery bank, and a grid tied inverter, that's all you need.

[rmusada]

If we use the Sunny Island 8.0H we don’t need other controller to regulate PV the balance between the energy feed in and energy used ? Our set up is PV grid tie with 10Kw panel using 2 Sunny Boy Inverter. We want to go off grid. What is the maximum size of the generator that we can connect to a Sunny Island 8.0H ?

Thank you.

[Salts]

I have the Sunny Boy solar system, so I'm familiar with that part. This Sunny Island battery system that works with the Sunny Boy solary system when disconnected from the grid is intriguing. As you know, the Sunny Boy normally just has the 1000w secure power supply that provides some power from the panels when disconnected from the grid.

If I'm understanding this correctly, the Sunny Island will access the full power of the Sunny Boy solar system to charge the battery bank. Between the SI and SB, the load from the home is met and any excess power is directed back to the batteries. What happens when the battery bank runs low at night? How do you keep the batteries charged when totally isolated? Why would the SI system be anymore sensitive to lighting than the SB system?

Pictures would be great if you don't mind sharing.

Yes, the Sunny Islands (SI) make a grid-quality power which causes the Sunny Boy's to think the grid is active and they start making power as well. The SI will use excess power from the SB to charge batteries. If the batteries are already charged and the SB are making too much power for the loads, the SI will throttle the SB through Frequency Shift Power Control. (No special hardware needed).
When my 16.5kw bats came to full charge, the SI units initiate the Frequency shift and the SB inverters were only allowed to make just enough power to keep the house going. The system works amazingly well. When my 240 well water pump kicked in, the lights in the house didn't even flicker..

If your battery bank runs dry at night, (which should not happen with a properly designed system), then the SI units can automatically start a generator to power loads and charge the batteries.

The Sunny Islands are no more or less sensitive than the Sunny Boy inverters as far as I know.. they're just a hell of a lot more expensive, and since I have the option to isolate them when not being used, I do it.
By isolating the off-grid system, not only would it save the Sunny Islands, but it would also save the $800 BMS..

I'll have to work on photos.. had to dump my computer.. running on different system right now until I get a new motherboard. Every 4 years like clockwork.

[sabersix]

I have the Sunny Boy solar system, so I'm familiar with that part. This Sunny Island battery system that works with the Sunny Boy solary system when disconnected from the grid is intriguing. As you know, the Sunny Boy normally just has the 1000w secure power supply that provides some power from the panels when disconnected from the grid.

If I'm understanding this correctly, the Sunny Island will access the full power of the Sunny Boy solar system to charge the battery bank. Between the SI and SB, the load from the home is met and any excess power is directed back to the batteries. What happens when the battery bank runs low at night? How do you keep the batteries charged when totally isolated? Why would the SI system be anymore sensitive to lighting than the SB system?

Pictures would be great if you don't mind sharing.

[Salts]

I'm interested to see how you have this setup. Can you post a diagram and/or some pictures of your setup?

Which part?

There really isn't much to the system. The Grid Tied Sunny Boy's are hooked up like every other solar array and feed power into my circuit breaker box. Nothing at all different there.

Then I have a large box (3ft x 4ft x 22 inches deep) that contains my battery and BMS. The positive and negative from the bats connect to the Sunny Island (SI) inverters. About the only significant difference with mine is that the SI inverters are not hard-wired to my breaker box, I connect the system with a 6ga 4 wire SO cord so that the inverters are totally isolated when not being used. I just connect the cord, flip an interlock breaker that isolates the grid, and I'm up and running.

I didn't hard wire them in as normal for fear that a lightening strike could destroy my expensive equipment.

Here's a diagram of how they are normally hooked up. Its pretty straight forward.

sunnyisland.jpg

[sabersix]

I'm interested to see how you have this setup. Can you post a diagram and/or some pictures of your setup?

[Salts]

Yes, I call Sunny Island the Cadillac of hybrid solar systems. Not cheap though!

Per your signature line, I'm upgrading my 16.5kw Chevy Volt batteries and going to be using Chevy BOLT batteries. 40kw worth.. Just haven't finished putting them together yet.

LG Chem cells are the best in the world.