Anti islanding

[nomadh]

A few UL compliant solar inverters can produce power from just solar power but the power is unpredictable and can collapse at anytime from a passing cloud. For stable power a reliable grid quality power source to activate grid-tied soar inverters and a way to absorb or limit excessive power grid tied solar inverters are necessary. There is no inherent reason why the solution requires battery but some kind of stable energy resource is necessary.

Not likely with my sunnyboy. It's a 5kw system but the daytime power is just 1500w. In testing it can put out 400w out of 600 at near dawn and dusk but your right that clouds could knock it out but after it has 2500 watts output it handles the 1500 fine.

[nomadh]

Hi all, I'm just ordering a solar panel/battery system which will be linked to the grid and have become aware of a safety feature called "anti-islanding". As I understand it if the grid goes down then the solar panel/battery system are shut down to prevent electrical current going back into the grid and endangering personnel working on the grid.

The consequence is that should the grid go down you also have no access to your battery or solar panel power.

I'm guessing this is a feature of the inverter and was wondering if there are any available that would isolate you from the grid but not turn off your in house power.

Your system request Make's total sense to me. The fact that no system had that available was the reason I didn't get solar for years. It was luck that sunnyboy had just come out wth an inverter with daytime emergency power just before the ca nem 1 ended.
it's tl us series. I hear they don't allow it in ca now because it has live power on the roof during fire? but i dont know. People here act like this is crazy or a brand new concept or cray dangerous. Mine is very simple I throw a switch to disconnect from the grid and then I can get 15 amps during the day without a battery.

I'm just now catching up on new tech and it looks like the new iq8 enphase had a no battery daytime power option too. Hopefully they allow it in ca.

[SunEagle]

This is true based on a Harbor Freight generator which my Nephew purchased. The sine wave is very dirty. However, not all generators are the same. More expensive generators which use inverters for output are reportedly able to produce a cleaner signal. My preference is batteries anyway.

There may be some form of power generation out there that can fool an inverter but as far as I know there isn't any small home sized ones that can do that even if they are inverter type and have a clean wave form. But again solar inverters are being changed and maybe something other then batteries will make them work to their full potential.

[Ampster]

And before anyone suggests it a generator will not provide that same electrical performance as the grid or battery system so the inverter will not work if you just have a generator.

This is true based on a Harbor Freight generator which my Nephew purchased. The sine wave is very dirty. However, not all generators are the same. More expensive generators which use inverters for output are reportedly able to produce a cleaner signal. My preference is batteries anyway.

[SunEagle]

A few UL compliant solar inverters can produce power from just solar power but the power is unpredictable and can collapse at anytime from a passing cloud. For stable power a reliable grid quality power source to activate grid-tied soar inverters and a way to absorb or limit excessive power grid tied solar inverters are necessary. There is no inherent reason why the solution requires battery but some kind of stable energy resource is necessary.

And before anyone suggests it a generator will not provide that same electrical performance as the grid or battery system so the inverter will not work if you just have a generator.

[solardreamer]

A few UL compliant solar inverters can produce power from just solar power but the power is unpredictable and can collapse at anytime from a passing cloud. For stable power a reliable grid quality power source to activate grid-tied soar inverters and a way to absorb or limit excessive power grid tied solar inverters are necessary. There is no inherent reason why the solution requires battery but some kind of stable energy resource is necessary.

[albert436]

I've got a solar guy coming over here in about an hour and I will try to remember to ask him that is if I can remember the question which is a little over my head . . .

[SolTex]

At least one manufacture (that I know of) does have a system that will provide limited backup operation, without batteries, when the grid goes down. There may be others.

https://enphase.com/installers/systems/sunlight-backup

[Srrndhound]

But the reason is a perhaps, I'm going to ask around a bit and see if I can understand why this would be. what is the battery buffering from what ?

From fluctuations in solar generation. But this is just my guess -- I have not heard a full explanation why a battery must be present in order for the system's inverter output to made suitable for local consumption.

Another question, maybe already answered -- if you do NOT have a battery, then can your solar panels power you in a blackout? I mean during the daytime of course

That appears to be the rule -- no battery, no backup. I hope someone will provide the background for this.

[solardreamer]

Not regardless of the inverter. The inverter has to be specifically designed for backup operation.

Not just a battery. You need a hybrid battery inverter system that can isolate your grid-tied solar system via a transfer switch from the grid and also generate grid quality AC power to form an island grid in order to activate your grid-tied solar inverters.

[albert436]

Any system that can feed the grid must automatically disconnect from the grid during an outage. It's a safety thing for grid repairs.

It may seem odd, but PV systems must have a battery in order to enable the system to supply your house during an outage, even though the PV panels may be capable of significant power by themselves. Perhaps the reason for that is the batteries act as a local buffer to stabilize operation.

Yes does seem unexpected but interesting to learn what the real deal is.

But the reason is a perhaps, I'm going to ask around a bit and see if I can understand why this would be. what is the battery buffering from what ?

Another question, maybe already answered -- if you do NOT have a battery, then can your solar panels power you in a blackout? I mean during the daytime of course

[Srrndhound]

Ah perhaps it was my misunderstanding.....so a grid tied PV panel/system with a battery will still operate to supply the owners home in a power outage regardless of the inverter used?. Is that correct?

Allow me to rephrase. The system has to be specifically designed for backup operation. This capability may be provided by a separate component, as in the Solar Edge Backup Interface, or that could be part of the inverter unit.

[Techno]

It may seem odd, but PV systems must have a battery in order to enable the system to supply your house during an outage, even though the PV panels may be capable of significant power by themselves. Perhaps the reason for that is the batteries act as a local buffer to stabilize operation.

Ah perhaps it was my misunderstanding.....so a grid tied PV panel/system with a battery will still operate to supply the owners home in a power outage regardless of the inverter used?. Is that correct?

[Srrndhound]

OK so do these setups typically disconnect from feeding power back to the grid when there is an outage?

Any system that can feed the grid must automatically disconnect from the grid during an outage. It's a safety thing for grid repairs.

Are you typically able to then use your solar panels to tide you over during a daytime blackout?

It may seem odd, but PV systems must have a battery in order to enable the system to supply your house during an outage, even though the PV panels may be capable of significant power by themselves. Perhaps the reason for that is the batteries act as a local buffer to stabilize operation.

[albert436]

Could anyone clarify something very basic for me?

Is there a typical setup for an area like mine, which is in California, (I happen to be on SDGE)? Eg. using typical equipment such as SunnyBoy string inverters or Enphase microinverters.

OK so do these setups typically disconnect from feeding power back to the grid when there is an outage?

Are you typically able to then use your solar panels to tide you over during a daytime blackout?

I know, there are many different systems out there but I bet there is at least a majority that are set up in very similar ways.

I don't remember where you guys are all located and I understand that different regulations etc apply in different places.

So what's the normal deal out here.

Is there one setup when there is a battery vs no battery? I mean in terms of isolating from the grid etc.

Thanks everyone, just trying to get a grasp on the overall subject, which is one that would never have occurred to me.