Can I get some last minute advice before signing contract?

[SunEagle]

Thanks for these inputs, they are very helpful. He came back with the generator quote and something is amiss -- $15k for a generac generator!!!! The most expensive residential application is only $5700 and the 10KW which should be sufficient for my needs is about half that. The 48kw commercial generator is about that price so I think there was an error in the quote.

Is that $15k price for the generator, fuel tank and installation?

If so that is really not a bad price depending on the size fuel tank and kw rating of the generator.

[mikedunkel]

Is that $15k price for the generator, fuel tank and installation?

If so that is really not a bad price depending on the size fuel tank and kw rating of the generator.

I already have a buried LP fuel tank with lines running to the house. I had previously received a quote for a stand-alone generator which duplicates a lot of the safety wiring they are planning on doing for the solar install anyway, and that quote was under $10k.

EDIT: and I just got an email from my installer, the price was incorrect. New quote is $8k for a 14kw generac + whatever it costs for me to have someone come to the house and connect the generator to the LP which I doubt would be more than $300-$500.

[mikedunkel]

Typically you oversize in the 1.2 range. This is over 1.5. Anything over 1.3 and you essentially hit diminishing returns. For a 7.6 kW inverter I would be looking at around 9.1 kW worth of panels. Now, unless because you are doing a battery, there is something special that the battery needs that can justify that oversizing. Shading or odd roof peaks may justify this too. Otherwise, you could save a good chunk of money.

I think SolarEdge allows a max of 155%. It almost seems like your installer is just going for the max here???

As noted though, if you have some sort of split array in multiple directions, then I would not worry about it.

Thanks for your replies, I asked my installer and he is going to do something between a 50/50 and 66/33 split, my house is oriented 45 degrees off true north so I'll be getting panels on the SW and SE roof. I called and finalized the order, I really appreciate the tips and advice as they directly led to me removing the 2nd battery and instead getting the generator. Total cost will be reduced about $2k and the system will be a little better at doing what I want it to do.

[sabersix]

Thanks for your replies, I asked my installer and he is going to do something between a 50/50 and 66/33 split, my house is oriented 45 degrees off true north so I'll be getting panels on the SW and SE roof. I called and finalized the order, I really appreciate the tips and advice as they directly led to me removing the 2nd battery and instead getting the generator. Total cost will be reduced about $2k and the system will be a little better at doing what I want it to do.

Glad we could help. Do you plan to have the generator integrated with the solar system though the Backup Interface that is shown in the SolarEdge diagrams?

[mikedunkel]

Glad we could help. Do you plan to have the generator integrated with the solar system though the Backup Interface that is shown in the SolarEdge diagrams?

I made it clear to the installer that I expect a fully integrated system. He hasn't gotten back to me with specifics so maybe somebody here knows. Is the system smart enough that in the event of a grid outage but full sun, the generator will back down or completely turn off if the solar is handling the loads?

[hayhayday]

If the storedge is a energy hub inverter allows ratio of 2 as the excess power over 7.6kw can still be used to charge the batteries rather then being clipped so one inverter should be ok as it should reduce\eliminate clipping.

[bitslizer]

I don't think with the new setup that Tesla PV panel shutdown in a grid outage, they have to recharge the powerwall from solar panel during the day.

however, I'm not sure if Tesla (I have not ask or research into this) gateway can accommodate a backup generator.

[mikedunkel]

I don't think with the new setup that Tesla PV panel shutdown in a grid outage, they have to recharge the powerwall from solar panel during the day.

however, I'm not sure if Tesla (I have not ask or research into this) gateway can accommodate a backup generator.

I am not an expert on any solar system, but I paid my $100 to get an individual advisor and a quote derived by a human who works for Tesla, and my project advisor told me in no uncertain terms that Tesla solar panel systems DO NOT produce ANY electricity in the event of a grid outage. They don't power the house, they don't power the battery, they just turn off. I don't know how he or I could be any more clear on that point.

[scrambler]

I am not an expert on any solar system, but I paid my $100 to get an individual advisor and a quote derived by a human who works for Tesla, and my project advisor told me in no uncertain terms that Tesla solar panel systems DO NOT produce ANY electricity in the event of a grid outage. They don't power the house, they don't power the battery, they just turn off. I don't know how he or I could be any more clear on that point.

Either they did not understand, or they misled you

A full Tesla Installation does recharge during an outage, the gateway isolate the Inverter from the Grid.

Best Practices During Power Outages | Tesla Support


Quote:
"How Powerwall Provides Backup Power


When a utility power outage does occur, your Powerwall instantly disconnects from the grid and restores backup power to your home in a fraction of a second, over one hundred times faster than typical standby generators. This means your appliances keep running without interruption, and there’s no need to reset your clocks. You may not even notice when an outage occurs. Learn more about what Powerwall backs up.

If you have solar, your Powerwall can recharge from your solar system to run your home from solar and Powerwall even when the grid is down. A traditional solar system without a Powerwall does not function during a grid outage.

If more solar energy is produced than can be used or stored during an outage, Powerwall will turn off the solar system and turn it back on when the energy can be used again."

[SunEagle]

Either they did not understand, or they misled you

A full Tesla Installation does recharge during an outage, the gateway isolate the Inverter from the Grid.

Best Practices During Power Outages | Tesla Support


Quote:
"How Powerwall Provides Backup Power


When a utility power outage does occur, your Powerwall instantly disconnects from the grid and restores backup power to your home in a fraction of a second, over one hundred times faster than typical standby generators. This means your appliances keep running without interruption, and there’s no need to reset your clocks. You may not even notice when an outage occurs. Learn more about what Powerwall backs up.

If you have solar, your Powerwall can recharge from your solar system to run your home from solar and Powerwall even when the grid is down. A traditional solar system without a Powerwall does not function during a grid outage.

If more solar energy is produced than can be used or stored during an outage, Powerwall will turn off the solar system and turn it back on when the energy can be used again."

That makes more sense. Why have a solar pv system and battery that won't be charged if the grid goes down.

[mikedunkel]

Either they did not understand, or they misled you

A full Tesla Installation does recharge during an outage, the gateway isolate the Inverter from the Grid.

Best Practices During Power Outages | Tesla Support


Quote:
"How Powerwall Provides Backup Power


When a utility power outage does occur, your Powerwall instantly disconnects from the grid and restores backup power to your home in a fraction of a second, over one hundred times faster than typical standby generators. This means your appliances keep running without interruption, and there’s no need to reset your clocks. You may not even notice when an outage occurs. Learn more about what Powerwall backs up.

If you have solar, your Powerwall can recharge from your solar system to run your home from solar and Powerwall even when the grid is down. A traditional solar system without a Powerwall does not function during a grid outage.

If more solar energy is produced than can be used or stored during an outage, Powerwall will turn off the solar system and turn it back on when the energy can be used again."

I told the Tesla rep they were going to lose the sale if the panels went offline during a grid outage. I specifically asked why their competitors and why a generator can operate during an outage but not their panels. It was like talking to a non-interactive recording. He just kept repeating the same thing "Tesla solar panels will not produce electricity during a grid outage, once your battery depletes you will not have any electricity."

I found it hard to believe that was how their system operates but either way I wasn't giving them my business. Either their system sucks or they employ idiots. A company like that won't get my money.

[soby]

I have 10kW of solar panels hooked up to the SE7600 StorEdge with the RESU10H. During spring and fall, I do have clipping at 7.8kW AC but the excess is used to charge the battery. I normally keep the battery at 35% charge.

We don't usually have power outages and when we do they are 1-2 hours. The RESU10H at 35% is more than enough to power our 2Xfridges, freezer, 2Xfurnaces, on-demand hot water, internet infrastructure and office. It's a non-issue unless we are cooking or it's crazy hot out. We don't have A/C backed up and that is the only weakness of our system. 2X A/C condensers would eat up the battery very quickly.

The RESU16Hs are each rated at 7kW continuous but you will be limited by the inverter(s). My SE7600 can only handle 5kW DC regardless of the number of batteries and it looks like the SE7600H is no different. See here: https://www.solaredge.com/sites/defa...tasheet-na.pdf

With one inverter, you will still be limited to 5kW even with two batteries. That is one advantage of using two inverters. Then you would be limited to 10kW which is more than enough. I even question the ability to use 2X RESU16H on a single SE7600H. The spec sheet says Maximum Battery Capacity Per Inverter: 19.6kWh. That allows a single RESU16H or 2XRESU10H. If you really want to get the most out of the two battery system, you need that second inverter.

[scrambler]

I told the Tesla rep they were going to lose the sale if the panels went offline during a grid outage. I specifically asked why their competitors and why a generator can operate during an outage but not their panels. It was like talking to a non-interactive recording. He just kept repeating the same thing "Tesla solar panels will not produce electricity during a grid outage, once your battery depletes you will not have any electricity."

I found it hard to believe that was how their system operates but either way I wasn't giving them my business. Either their system sucks or they employ idiots. A company like that won't get my money.

You clearly spoke with an idiot

[mikedunkel]

I have 10kW of solar panels hooked up to the SE7600 StorEdge with the RESU10H. During spring and fall, I do have clipping at 7.8kW AC but the excess is used to charge the battery. I normally keep the battery at 35% charge.

We don't usually have power outages and when we do they are 1-2 hours. The RESU10H at 35% is more than enough to power our 2Xfridges, freezer, 2Xfurnaces, on-demand hot water, internet infrastructure and office. It's a non-issue unless we are cooking or it's crazy hot out. We don't have A/C backed up and that is the only weakness of our system. 2X A/C condensers would eat up the battery very quickly.

The RESU16Hs are each rated at 7kW continuous but you will be limited by the inverter(s). My SE7600 can only handle 5kW DC regardless of the number of batteries and it looks like the SE7600H is no different. See here: https://www.solaredge.com/sites/defa...tasheet-na.pdf

With one inverter, you will still be limited to 5kW even with two batteries. That is one advantage of using two inverters. Then you would be limited to 10kW which is more than enough. I even question the ability to use 2X RESU16H on a single SE7600H. The spec sheet says Maximum Battery Capacity Per Inverter: 19.6kWh. That allows a single RESU16H or 2XRESU10H. If you really want to get the most out of the two battery system, you need that second inverter.

Sounds like 2 batteries and just 1 inverter would've been silly. I ended up selecting the 11.3 kw of panels, single inverter, single battery, and 14kw generac generator.

[soby]

Sounds like 2 batteries and just 1 inverter would've been silly. I ended up selecting the 11.3 kw of panels, single inverter, single battery, and 14kw generac generator.

You wont regret it. That new RESU16H is impressive and coupled with the SolarEdge backup interface will get you through the shorter outages without a hiccup. The generator will kick in if the battery is depleted but I'm curious to know more about how the SolarEdge inverter and Generac will communicate and coordinate output when your household draw exceeds the 5kW max output of the inverter. I'm definitely jealous that the new SolarEdge interconnectivity allows your battery to power the entire house and not just a separate backup loads panel.