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

[LeeLewis]

Sorry for seemingly never coming back. I don't get emails about updates to the conversations.

What I'd like to do at this point is to test each of my inverters, sell them used and use those funds to help pay for the new setup I would go for.
I really don't care about getting grid returns, it's not adding up to much. I would be better off using the power, charging battery banks etc.

The problem is always the same. I cannot find any information on how to test those inverters.
This is what I think needs to happen.

1. Connect 240VAC to the inverter.
2. Measure the current.
3. Introduce a DC input from a panel to the inverter.
4. Unless the inverter is software output disabled, I should see an increase in current.

[Maitake]

Salt,
Does your system have a communication cable between Sunny Island and Sunny Boy?
I'm putting in a similar system, and have heard a rumor they eliminated the cable, and that Rule 21 setting must be used in order to avoid smoking the inverters.

thx

[jflorey2]

I'm trying to find a device similar to what you're talking about that would 'simulate' the grid so the solar system would keep running without connection to the grid.

I think we really need this in a FAQ because it's a question that gets asked very often and the answer is usually "no."

You could replace your string inverter with a Sunny Boy with the Secure Power feature. That would give you ~2000 watts of power when the grid is out AND the sun is out. Add a cheapo UPS to that and you'd get a little power at nighttime as well.

You could replace your string inverter with a real hybrid inverter with a battery (doesn't have to be big) and wire "its own breaker box" to the output. Then that breaker box would be backed up. For example, the Sol-Ark series will likely tie directly into your existing solar strings and do exactly what you want.

But if your goal is to take an everyday cheapo grid tie inverter and "trick" it into running when the grid goes away - there's no good way to do that cheaply.

[richmke]

Search for Solar Battery backup, a/c connected. You won't need a big battery, but you will need a battery. That is what generates the A/C to simulate grid connection for the panel. Inverter will be expensive.

BTW: You need something more than "just need a device that will allow a usable output and shut off or kill output if voltage/amps get too low." It also needs to be able to throttle the output of the panels if there is not enough load. When you are connected to the grid, the grid absorbs any excess. When you are off-grid, there is no where for the excess power to go.

[Ampster]

Yes, what you need is a hybrid inverter which can AC couple to your existing grid tie system. Hybrid inverters use DC batteries to invert the DC to AC to create the grid forming features needed to AC couple as mentioned previously by SunEagle . Hybrids are not distinguished by DC or AC designations. They use and create both DC and AC depending on the mode they are in. There are many brands from Outback, Schneider; SolArk, SMA and others. All of those can be installed behind the meter in such a way that they should not disrupt your arrangement with your power company. It is important to understand the terms of your Net Metering Agreement so that you are in compliance.

[LeeLewis]

My problem is not knowing the terminology as I've not had to play with my solar yet.
I'd like something simple and legal because we are grandfathered into a special deal with the power company where we get a good rate on our excess power so don't want to mess that up.

I believe in order to not mess that up, I need to tap into one of the panels *before* it reaches the power companies locked boxes.
From that panel, I could take the AC output from the soar, run it through a device that would keep the solar generating when grid goes down.
I would only bother if there was an extended outage so a manual transfer switch would be just fine.

In terms of output, I just need a device that will allow a usable output and shut off or kill output if voltage/amps get too low.
This device is one I've yet to learn what it would be called. It's not an inverter, it's some sort of manager that would prevent low voltage from being output if the solar is not outputting enough.

In terms of output, I can use either AC or DC. If AC, I could simply run a 48VDC charger to charge up a 48VDC battery bank. I have DC to AC inverters.
Or I could convert the AC to DC to charge batteries so in this case, I guess I'd need some sort of charge controller.

So it sounds like I only need three devices but it sounds like there are some devices that have all this built into one box. You mentioned the Sunny Boy so I looked that up and I think that's what I'm looking for and has all three things I need. Again, all new to me so lots and lots of learning but these forums and folks like you are certainly helping a great deal so I thank you for that.

[SunEagle]

Thanks.

I don't mean simulate the grid as in some kind of hack, I mean I've seen to many videos where solar installers are talking about devices that accept the solar AC input and uses the batteries to keep the solar system generating even if the grid goes down.

I'm having a heck of a time (learning) finding out what that kind of device is called since I'm not looking for DC to AC inverter with batteries but something that will accept the AC coming from the solar system and keep it running.

The only inverter that I know about is a Hybrid type which will either send AC to the main panel or DC to the batteries which could then send AC through an inverter to the specific loads.

I have not heard of an AC Hybrid inverter but then again with some of the new technology coming from Tesla and other battery manufacturers there may now be an AC Hybrid inverter.

[LeeLewis]

Thanks.

I don't mean simulate the grid as in some kind of hack, I mean I've seen to many videos where solar installers are talking about devices that accept the solar AC input and uses the batteries to keep the solar system generating even if the grid goes down.

I'm having a heck of a time (learning) finding out what that kind of device is called since I'm not looking for DC to AC inverter with batteries but something that will accept the AC coming from the solar system and keep it running.

[z80]

Maybe I'm missing it in this thread but are your inverters AC or DC? I cannot tell from the image, it's too small on my screen.
I have a grid tied 10.5KW system that I want to manually switch to batteries during extended outages. I don't want to tie it to the house, just its own breaker box and outlets from that.
My system however uses AC inverters so I'm trying to find a device similar to what you're talking about that would 'simulate' the grid so the solar system would keep running without connection to the grid. I'm looking online at Sunny boy devices mentioned but you've all mentioned a number of devices. I'll likely buy something older to save money. I don't need the full 10.5KW, 5KW or so would be plenty.

The sunny island system is an AC coupled system.
There are no seperate DC charge controllers or all the other goo that some systems like Victron need.
As others have said..you mount the SI on the wall...connect red and black to the battery bank, mount a sunny boy next to it,
hook them up with a common AC connection and Voila....it just works.

I cannot believe the rats nest mess that Victron systems need to manage all the functions that a sunny island does internally.

As for your idea about simulating the grid, no way you will ever get that to work, many have treed, many have had a big bang.
Reason is the grid is an infinite load whereas a battery bank is not.

Bite the bullet, commit to doing it properly and just buy a Sunny island. with at least one Sunny Boy...and get the 8.0H.

At least a 5kw Sunny Boy, older ones don't work...make sure it has a "TL" suffix in the model number.

enjoy...

[LeeLewis]

Maybe I'm missing it in this thread but are your inverters AC or DC? I cannot tell from the image, it's too small on my screen.
I have a grid tied 10.5KW system that I want to manually switch to batteries during extended outages. I don't want to tie it to the house, just its own breaker box and outlets from that.
My system however uses AC inverters so I'm trying to find a device similar to what you're talking about that would 'simulate' the grid so the solar system would keep running without connection to the grid. I'm looking online at Sunny boy devices mentioned but you've all mentioned a number of devices. I'll likely buy something older to save money. I don't need the full 10.5KW, 5KW or so would be plenty.

[Murby]

You are sure it was twenty thousand sunny islands?
I call BS on that....sorry.

Oops.. extra zero thrown in.

Here's the news release on it. The Sunny Islands were on ebay for months selling like hot cakes. GAGlobal auction sold most of their trailers (2 of the SI's on each), then more of the SI's new in boxes.

https://pv-magazine-usa.com/2019/05/28/dc-solar-gets-liquidated/

https://www.solarpowerworldonline.com/2019/05/dc-solar-auction-includes-unopened-solar-panel-pallets-combiner-boxes-sma-inverters/

[z80]

Brand new.. even came with the 10 year extended warranty which I verified with SMA via the serial numbers.

They were the result of a company called DC Solar going out of business because the company was a scam. The courts liquidated the company and dumped around 20,000 Sunny Islands onto Ebay.

You are sure it was twenty thousand sunny islands?
I call BS on that....sorry.

[Murby]

Are they used?

Brand new.. even came with the 10 year extended warranty which I verified with SMA via the serial numbers.

They were the result of a company called DC Solar going out of business because the company was a scam. The courts liquidated the company and dumped around 20,000 Sunny Islands onto Ebay.

[solardreamer]

Ya, the retail price north of $5,000 is kind of hard to justify.. Got two of them on ebay for $2200 ($1100ea) shipped to my door. My only mistake was not buying 4 of them. I kick myself now.

Are they used?

[Murby]

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

Our current net metering rules make going off grid financially stupid.. but that will change in 2027 when my 10 years is up and they change the net metering rules. Hopefully, by that time, there will be a lot more electric vehicles sitting at the salvage yards with nice healthy batteries.