How to tie a solar generator to the inverter

[fungi2b]

Let me start by saying I KNOW that you must disconnect from the grid BEFORE you energize your inverter, during a power outage. That being said, I would like to know how to wire my solar generator into the inverter to allow it to provide the current needed to allow the inverter to operate and supply the house with power during an outage. Thank you for any help or advice.

[ButchDeal]

What do you mean by solar generator?

there is no safe way to get a grid tie pv system without batteries to function without the grid except for an expensive AC coupled configuration which is complex and costly to get set up right.

[Mike90250]

..... I would like to know how to wire my solar generator into the inverter to allow it to provide the current needed to allow the inverter to operate and supply the house with power during an outage. .....

I would like to know what a solar generator is too. To me, it sounds like marketing mumbo-jumbo.

[fungi2b]

A solar generator is a system of panels, batteries, and an inverter that converts light to 120 VAC ......there are lots of them on the market. Many put out a pure sine wave, just light the grid provides. Since a PV system uses the grid power to determine its on/off status...I am interested in fooling the PV inverter into thinking the grid is up, when it is actually down, using the pure sine wave of the solar generator. I hope that clarifies my question.

[nwdiver]

A solar generator is a system of panels, batteries, and an inverter that converts light to 120 VAC ......there are lots of them on the market. Many put out a pure sine wave, just light the grid provides. Since a PV system uses the grid power to determine its on/off status...I am interested in fooling the PV inverter into thinking the grid is up, when it is actually down, using the pure sine wave of the solar generator. I hope that clarifies my question.

AC Coupling

https://www.magnum-dimensions.com/sites/default/files/MagArchive/AN-0002-AC-Coupling-Rev-5-10.pdf

[ButchDeal]

A solar generator is a system of panels, batteries, and an inverter that converts light to 120 VAC ......there are lots of them on the market. Many put out a pure sine wave, just light the grid provides. Since a PV system uses the grid power to determine its on/off status...I am interested in fooling the PV inverter into thinking the grid is up, when it is actually down, using the pure sine wave of the solar generator. I hope that clarifies my question.

That is just an off grid system. "Solar Generator" is just a marketing term and could mean just about anything.

The question about fooling your grid tie system into workin is asked repeatedly here

Short a answer:
You are NOT going to fool the grid tie system with a cheap off grid system.
What you are talking about is called AC coupling and it requires a more complex bimodal system not a cheap off grid system.
The bimodal system must be larger than the grid tie system and capable of taking the full charge rom the grid tie system as well as the battery bank.
It must be capable of controlling the grid tie system as well.

Further if you did "fool" your grid tie system to come one (all its safeties failed in some way) then before very long it would be pumping its full capacity with no place to go but into your off grid (solar generator) and likely that would be the end of either the grid tie system, the solar generator, or something else important.

[fungi2b]

Thanks to NWDiver for that article on AC coupling. I don't understand ButchDeal's last post, in that my solar system was operating for 2 months waiting on the utility company to install a meter...all the time producing 45+Kwh everyday, which went nowhere and did nothing...with no apparent problems....so is the problem occur when the power used is less than the power being produced, and the excess is feeding into the solar generator...burning out the solar generator batteries?

[nwdiver]

Thanks to NWDiver for that article on AC coupling. I don't understand ButchDeal's last post, in that my solar system was operating for 2 months waiting on the utility company to install a meter...all the time producing 45+Kwh everyday, which went nowhere and did nothing...with no apparent problems....so is the problem occur when the power used is less than the power being produced, and the excess is feeding into the solar generator...burning out the solar generator batteries?

That statement doesn't make much sense... if it 'went nowhere and did nothing' then it wasn't produced.... are you asking what happens to the solar energy that hits solar panels that aren't operating? It's just dissipated as heat on the panels.

[inetdog]

Thanks to NWDiver for that article on AC coupling. I don't understand ButchDeal's last post, in that my solar system was operating for 2 months waiting on the utility company to install a meter...all the time producing 45+Kwh everyday, which went nowhere and did nothing...with no apparent problems....so is the problem occur when the power used is less than the power being produced, and the excess is feeding into the solar generator...burning out the solar generator batteries?

Yes, the root problem is that a standard grid tie inverter has no way to throttle itself down to output less power than the maximum that the panels are currently capable of producing. The grid is capable of aborbing and distributing that power. A "solar generator" system cannot accept that excess of production over consumption.

[ButchDeal]

Thanks to NWDiver for that article on AC coupling. I don't understand ButchDeal's last post, in that my solar system was operating for 2 months waiting on the utility company to install a meter...all the time producing 45+Kwh everyday, which went nowhere and did nothing...with no apparent problems....

ok ok. HOW IN THE HELL did your system PRODUCE 45+kWh every day that went nowhere and did nothing.

If you system was OPERATING then it produced the power and it went to the grid.
If your system was NOT operating which would be normal for one waiting for utility company to give PTO (Permission To Operate), then NO power was generated at ALL, as the system would have been turned OFF.

so is the problem occur when the power used is less than the power being produced, and the excess is feeding into the solar generator...burning out the solar generator batteries?

If you have a grid tied system turned ON but without a grid connected to it, in an AC coupled configuration with a properly configured bimodal inverter and batteries then the AC coupled system generates all the power it can, and the bimodal system crams that power into the batteries as fast as it can (less any amount that was consumed instantly by loads).
If for some reason the bimodal inverter can not handle all the power or the batteries can not handle all the power then normally the bimodal inverter will either turn off or throttle back the grid tie inverter.
If it can not do this (improperly configured) then were does the extra power go.... into the batteries (that are full) and boiling them producing hydrogen and oxygen until such time as the batteries lose enough liquid that internal sparks ignite the explosive mix .....

Or less dramatically the bimodal inverter can't handle the power and it shorts out with some level of smoke likely significantly less than the battery explosion ...

[jflorey2]

A solar generator is a system of panels, batteries, and an inverter that converts light to 120 VAC ......there are lots of them on the market.

OK great. You can get one of those and use the output to charge cellphones, laptops etc. It CANNOT "fool your grid tie inverter" to get it to start up and give you power.

Many put out a pure sine wave, just light the grid provides. Since a PV system uses the grid power to determine its on/off status...I am interested in fooling the PV inverter into thinking the grid is up, when it is actually down, using the pure sine wave of the solar generator. I hope that clarifies my question.

You can't.

To do that, and get to actually work, you would need a good 240VAC bidirectional battery backed inverter that is rated higher power than your grid tied system. So if you have a 9kW system you'd need two Radian inverters ($4000 each) a battery bank ($2000 or so) and the usual balance of system stuff. Then you'd need to configure it for AC coupling. Call it $8000-$10,000 for the system.

A generator, on the other hand, will run you $800 and run everything in your house for days.

Another alternative, if you have a string inverter, is replace it with an SMA inverter with a secure power output. That gives you 2000 watts of solar power when it's sunny out - and gives you nothing when it's not.

[fungi2b]

My system was on the roof, absorbing the sunlight and, by default, producing electricity, even though the electricity had no place to go (inverter was OFF waiting for power company to install their meter)..once the meter was installed the inverter was turned ON and the power was now allowed to flow to my panel and to the grid. The panels do not have an on/off switch...they produce when struck by sunlight, no matter what. So, I am less inclined to listen to someone who has not grasped this fundamental principle....when I look for correct knowledge in the more advanced principles of solar use. No offense, I hope. NWDiver's and inetdog's explanations seem logical and knowledgeable...Thank you My investigation would seem to indicate that the battery system ADDITIONAL inverter, added to the grid-tied system, solves the problem of excess power to the batteries by shutting off (controller) the power to the batteries once they are fully charged...is this correct?

[fungi2b]

jflorey2....so, are you saying that the inverter can tell the difference between the grid sine wave and the generator sine wave? If so, how....if both are pure sine wave signals? Remember...none of this is AUTOMATIC....I would be disconnecting from the grid manually, before attempting to get the house powered by the solar panels...

[Mike90250]

While both are "pure sine wave" the Grid has some inherent qualities, that the GT inverter tests for, before outputting power. Intentionally very difficult to fool.. Sometimes, a large inverter generator can fool it, but once the PV power exceeds the household loads, the GT inverter will start cooking things by pushing power into the generator and raising the house power to high voltages.

and BTW, just because you are unable understand our explanations, does not mean we are incorrect, it simply means we've not discovered the proper level to instruct at.

But by all means, fire it up and stand outside and watch the flames. We've told you it's not going to end happily, till you add a huge battery and a bi-modal inverter $$$

[jflorey2]

jflorey2....so, are you saying that the inverter can tell the difference between the grid sine wave and the generator sine wave? If so, how....

Several ways.

1) Your generator generates 120 volts. The grid tie inverter needs 240 volts.
2) Your generator has a high output impedance. Even if you got a transformer and boosted it to 240 volts, as soon as you put any appreciable power on the grid the voltage would rise; the grid tie inverter would sense this and shut down.
3) If the inverter did start operating momentarily, and put several kilowatts of power into the output of your "solar generator" it would vaporize it, since it is not designed to handle an inverter feeding power back INTO it. Then the inverter wouldn't give you that nice sine wave any more, the grid tie inverter would sense it and shut down.

Keep in mind that grid tie inverters that do NOT get off the grid quickly can kill utility workers very easily. That same transformer that drops 13,000 volts to 240 volts for your use will happily step your 240 volts back up to 13,000 - and barbeque people working on the downed lines. Thus, grid tie inverters are designed to be very hard to fool.

(Fun thing that some people have tried - connect a 240 volt generator and try to get that to "fool" the panels. Unlike a cheap solar generator, an AC generator actually IS bidirectional, and can be spun by an external source. The grid tie inverter would spin the generator faster and faster until it either came apart or the frequency rose above the limit of the grid tie inverter, and it would shut down again.)

if both are pure sine wave signals? Remember...none of this is AUTOMATIC....I would be disconnecting from the grid manually, before attempting to get the house powered by the solar panels...

Right, we know that. It still wouldn't work.

This is like the #4 most common question asked here.