My new solar and Powerwall installation

[Cosmacelf]

I believe the SolarEdge system does not need a dump load. Remember that the SolarEdge architecture has an active electronic optimizer at each panel. The inverter communicates with each optimizer (over the DC power wiring) and can tell the optimizer show much power to release to the DC power bus. So in the case of being off grid, sun shining during the day, battery full, and the house load being less than what the panels can provide, the SolarEdge inverter just produces less power from each panel - it is matching load and supply.

Yet another reason why the SolarEdge optimizer architecture is superior than traditional string inverters.

 

[Garlan Garner]

I may have missed it in the thread.

When grid goes down, your electricity in the home can be run from the Solar + Battery, correct? You still have to reboot the PCs after the grid failure, but after the solar/battery combo comes up.

That means you "act like" you are off-grid - while the grid is down. However, when solar is mid-day, it may be producing excess power over your circuits aggregate demand. If you follow that, I was wondering what in the system "dumps" excess power or does SolarEdge shunt some of the modules somehow and only let through power enough to run the home's demand. In a traditional hybrid-solar system, the charge controller would have a circuit to route the Solar PV elsewhere, like hot-water heater, space heaters, that kind of thing. What I'm mainly talking about is a "dump load" circuit. Like this: Using a high power resistor as a dump load

Ecarfan has a fabulous system. I am currently switching away from my outback battery backup system to Powerwall.

My SolarEdge Inverter is the brains of the operation. The inverter makes the decision whether to accept power from the Solar Panels or the Powerwall. When the power goes out... The Inverter senses the grid loss and sends power from the either the powerwall or Solar Panels to the "backed up loads" ( see the picture below ). The Inverter constantly monitors the "grid" to check for AC. Upon Grid restoral...the Inverter powers down the panels - re-connects itself to the grid - powers up the panels.

 

[Garlan Garner]

I believe the SolarEdge system does not need a dump load. Remember that the SolarEdge architecture has an active electronic optimizer at each panel. The inverter communicates with each optimizer (over the DC power wiring) and can tell the optimizer show much power to release to the DC power bus. So in the case of being off grid, sun shining during the day, battery full, and the house load being less than what the panels can provide, the SolarEdge inverter just produces less power from each panel - it is matching load and supply.

Yet another reason why the SolarEdge optimizer architecture is superior than traditional string inverters.

My SolarEdge Inverter shuts off optimizers. That essentially disconnects the panels from the Inverter. Its safe. Now...there are 2 versions of Inverters. The newer inverters shut down optimizers. The older inverter shuts itself down ( however leaves the batteries connected to the inverter to power the backed up loads).

There is no need for a load.

 

[Cosmacelf]

AFAIK, the automatic transfer switch and auto transformer are two separate functions and devices in the Solaredge architecture. Yes, the above description in another post of the auto transformer comes from a sales blurb about the auto transformer, but I believe the only function it provides is split phase balancing when the system is disconnected from the grid.

Basically, when off grid, your home is going to draw more power from one 120V leg versus the other, and the auto transformer balances the power between the legs. The system would still function without an autotransformer, but you would limit your maximum power output when the power draw is unbalanced across the legs (which they almost always are).

More info on the Solaredge battery backup architecture here:

http://www.solaredge.com/sites/default/files/storedge-grid-tied-and-backup-na.pdf

 

[ecarfan]

When grid goes down, your electricity in the home can be run from the Solar + Battery, correct? You still have to reboot the PCs after the grid failure, but after the solar/battery combo comes up.

Your first statement is correct. But there is no need to "reboot the PCs" at my house, they are all notebook computers that have batteries.

Nothing in my house "crashes" when the grid goes down.

 

[ecarfan]

I was wondering what in the system "dumps" excess power

As I said just upthread, in response to the same question you just posted, my system automatically exports power back to the grid when my solar is generating more than I am currently requiring.

A near as I can tell, you keep asking me the same question, and I keep giving the same answer. My apologies if I am not understanding your question.

 

[bonaire]

As I said just upthread, in response to the same question you just posted, my system automatically exports power back to the grid when my solar is generating more than I am currently requiring.

A near as I can tell, you keep asking me the same question, and I keep giving the same answer. My apologies if I am not understanding your question.

It's a different question. If there is no grid (ie. the local substation is "offline") you cannot dump to the grid. You will be "islanded" and the power cannot leave your house or risk harming line-men outside.

And anyway - the idea is when the grid goes down (if) - does the system compensate for the excess mid-day power of the Solar array if your house is not having as much draw from the system. You cannot dump on the grid when it is down. but that's a rare condition. I don't know if the installer went over that scenario but it is something to plan for.

I am going to study the other guy's note above - regarding "sending power from the Solar PV to the circuits or the powerwall".

My mistake on WannabeOwner (on a previous page) was the one who said his computers needed to be rebooted - you have laptops which are great for that cutover period, of course.

 

[bonaire]

Ecarfan has a fabulous system. I am currently switching away from my outback battery backup system to Powerwall.

My SolarEdge Inverter is the brains of the operation. The inverter makes the decision whether to accept power from the Solar Panels or the Powerwall. When the power goes out... The Inverter senses the grid loss and sends power from the either the powerwall or Solar Panels to the "backed up loads" ( see the picture below ). The Inverter constantly monitors the "grid" to check for AC. Upon Grid restoral...the Inverter powers down the panels - re-connects itself to the grid - powers up the panels.

View attachment 191640

The Inverter senses the grid loss and sends power from the either the powerwall or Solar Panels to the "backed up loads" ( see the picture below ).

Ok, so the inverter has load management and can supply up to how much KW during mid-day when the grid is out? Full power of the solar PV or a fraction? I know SMA had their TL model which was only 15A of 120V per inverter during grid outage. If SolarEdge is able to much more power during mid-day, that is great.

I read the datasheet and it appears SE7600A can be 5000W of backup power. Pretty good. I imagine that the backup circuits could work mid-day too without a battery in the system, just good sun and large enough array

 

[Scrith]

Nice system. I've resisted getting a Powerwall becuase, for now, I just don't need it due to the fact that I generate more electricity than I use (PG&E EV plan in Redwood Shores, only a 3.95kWh SunPower/SolarEdge system with 13 panels and optimizers powering my 4BR/3BA home and a Tesla Model X90 and a Mercedes B-Class EV). I was about even last year (I ended up owing $20 for the year) on the PG&E TimeOfUse (TOU) plan, but now that I'm on the EV plan my generation credits are far greater than my usage (I'm +$400 for the year with 3 months to go).

 

[miimura]

When the grid goes down you cannot push excess solar generation out to the grid. If the solar is generating more than the critical loads need and the battery can take, then the inverter will just shift the MPPT point away from the optimum and the panels will naturally generate less power. This is how the system curtails the generation to match the demand. You only need a dump load on an off-grid system if you don't have a way to curtail the renewable generation.

 

[bonaire]

When the grid goes down you cannot push excess solar generation out to the grid. If the solar is generating more than the critical loads need and the battery can take, then the inverter will just shift the MPPT point away from the optimum and the panels will naturally generate less power. This is how the system curtails the generation to match the demand. You only need a dump load on an off-grid system if you don't have a way to curtail the renewable generation.

This is what I learned in the thread and why the SolarEdge beats out other inverters for this feature. I guess in the future, all inverters would do this (I would hope that also Enphase would eventually do this for off-grid type living with inexpensive solar AC). The older string inverters were not designed with this in mind - but the new stuff appears to all be working toward a blended standby solution with or without batteries. Good for the industry. Bad for some of us who have older systems

 

[AB4EJ]

This is what I learned in the thread and why the SolarEdge beats out other inverters for this feature. I guess in the future, all inverters would do this (I would hope that also Enphase would eventually do this for off-grid type living with inexpensive solar AC). The older string inverters were not designed with this in mind - but the new stuff appears to all be working toward a blended standby solution with or without batteries. Good for the industry. Bad for some of us who have older systems

Don't feel bad about your older system. Depending on utility policies, you may be better off. My elaborate Solar Edge installation ($21k after federal tax credit) I project will save me a big fat $82 per month, for a 256 month breakeven period; this is due to utility policy in AL.

 

[Garlan Garner]

The Inverter senses the grid loss and sends power from the either the powerwall or Solar Panels to the "backed up loads" ( see the picture below ).

Ok, so the inverter has load management and can supply up to how much KW during mid-day when the grid is out? Full power of the solar PV or a fraction? I know SMA had their TL model which was only 15A of 120V per inverter during grid outage. If SolarEdge is able to much more power during mid-day, that is great.

I read the datasheet and it appears SE7600A can be 5000W of backup power. Pretty good. I imagine that the backup circuits could work mid-day too without a battery in the system, just good sun and large enough array

Absolutely Yes. The inverters ( I have 2 - one per side of my 240AC supply ) can supply power to the backup circuits via the Solar Panels without the battery, however I had a few problems with that. When the PV array is not able to provide enough DC for the Inverter to keep the load running....the Inverters don't shut off as I would like them to. The Inverter allowed the AC voltage to get down to 105VAC and my refrigerator started clicking and my OLED TV started doing some strange things. I called SolarEdge about it and it was a matter of changing some options in the Inverter. Now they won't produce and AC <120. They shut off.
I don't have a PowerWall. I have (4) 500AH AGM batteries and they work great. I'm getting a Powerwall like ecarfan to see how it works.

Lastly, You can't run 240 without the grid because the Inverters are independent. The inverters phase drift. Some times they are in perfect phase with one another. Of course 120V appliances on either side of the panel don't care. Just wanted to add that.

Anyway. I am happy for ecarfan as his system looks great. I know he/she will be happy with it.

 

[Garlan Garner]

This is what I learned in the thread and why the SolarEdge beats out other inverters for this feature. I guess in the future, all inverters would do this (I would hope that also Enphase would eventually do this for off-grid type living with inexpensive solar AC). The older string inverters were not designed with this in mind - but the new stuff appears to all be working toward a blended standby solution with or without batteries. Good for the industry. Bad for some of us who have older systems

Yeah, unfortunately string inverter PV's are ALWAYS ON. In that case - Outback systems would be best. They are expensive, however they have a solution.

 

[Garlan Garner]

I'm going to be honest. Although this is a Tesla site....Powerwalls are very expensive and very large for the power they put out. Hopefully the price will come down soon.

 

[Chopr147]

I'll have to get back to this thread when I have a chance. I also have a 10kwh system and am waiting for the Powerwall price to come down.
I have an upstate house with an appointment in September with Solarcity to get a 5kwh system. I asked about Tesla owner special- nothing yet

 

[Cosmacelf]

Garlan, you have an unusual setup. A new SolarEdge/Powerwall setup will have an inverter that outputs 240V, so they can indeed power 240V appliances off grid. But do note that it unusual to have a 240V device on your critical load panel.

 

[Garlan Garner]

Garlan, you have an unusual setup. A new SolarEdge/Powerwall setup will have an inverter that outputs 240V, so they can indeed power 240V appliances off grid. But do note that it unusual to have a 240V device on your critical load panel.

I agree....The inverters can output 240V, however because I have 2 inverters I have to have to use them independently at 120VAC. I can't set both of them to 240VAC out because the phases won't always be the same.
Good thing I can connect the Powerwall to both inverters at the same time....because I can't afford 2 of them.

 

[Cosmacelf]

Garlan, do you know if that problem you have is generic to all household inverters? Is the problem that they can phase lock onto the grid, but can't phase lock onto each other absent the grid?

 

[Garlan Garner]

Garlan, do you know if that problem you have is generic to all household inverters? Is the problem that they can phase lock onto the grid, but can't phase lock onto each other absent the grid?

I'm not sure its a problem. If you have 1 inverter you can provide 240VAC to your backup loads and if you have 2 inverters you can also provide 240VAC to your backup loads as well.

Now that I think about it....a 240vAC unit like a whole house AC won't have enough startup power from the Solar Edge Inverters anyway.

However.....Outback systems have solved this issue with their expensive high powered systems but for the average house....its not that serious.