Solar Panels Design

[slcasner]

My solar roof installation was just completed yesterday. The plans show a "Rapid Shutdown Switch" but there is no Bozo's nose on the wall.

 

[KHYE]

My solar roof installation was just completed yesterday. The plans show a "Rapid Shutdown Switch" but there is no Bozo's nose on the wall.

You are lucky that your city has better taste. Do you have PW? The bozo nose is for shutting off ESS.

 

[yblaser]

You are lucky that your city has better taste. Do you have PW? The bozo nose is for shutting off ESS.

I think the button is unique to the PW 2+. To shutdown the solar system and activate the mid circuit interrupters on the roof you need to cut power to the inverter. Since the PW 2+ had an integrated inverter you can't use a normal blade disconnect (or the breaker) to cut power to the inverter since it can be powered by the PW 2+ internally.

 

[Fruitcake]

Another PW would be nice and ideal but everything is out of my pocket since I can't get the SGIP rebate. The only thing I have to run is AC but I will try to minimize its usage. Stove, oven, dryer, furnace and water heater are all gas. I have also installed a wholehouse fan myself and my AC usage is way less now in the evenings unless it's very humid outside.

Forget running your AC - I would be worried about STARTING your AC, with just one Powerwall, in an off-grid/outage scenario.

A single Powerwall can supply 30A. That's it. The only way to increase your amperage is to add more Powerwalls.

Some AC compressors can require more than 100A (!) or more to start. It's a specification that can be found on your compressor called LRA, short for Locked Rotor Amps. So when your compressor tries to start, it will try to draw 100A (or more), and your lone Powerwall will give up and shutdown, and now your entire house is down hard.

So, check your AC compressor's LRA! If the LRA is low, like 20A or so, you're (probably barely) OK. Otherwise, there are several choices:

1. Add more Powerwalls (thereby increasing the max amperage your system can deliver).
2. Exclude your AC compressor from your backed up loads. This means you won't have any air conditioning during an outage. But, you won't overload and shutdown your system either.
3. Replace your AC compressor with a more modern compressor with a low LRA.
4. Get a "Soft Start" capacitor for your compressor. These will store hundreds of amps in advance, so that when your compressor starts, it will draw that huge surge of power from the capacitor and not your Powerwall.
5. Do nothing and drink heavily.

Me? I have two Powerwalls and a hog of a compressor (160 LRA) with a Soft Start. Starts with no problems whatsoever.

Fruitcake

 

[slcasner]

You are lucky that your city has better taste. Do you have PW? The bozo nose is for shutting off ESS.

Yes, I have PW+ and PW2.

 

[holeydonut]

My solar roof installation was just completed yesterday. The plans show a "Rapid Shutdown Switch" but there is no Bozo's nose on the wall.

So you just have normal blade disconnect(s)?

Need pics of your new roof!

 

[KHYE]

Forget running your AC - I would be worried about STARTING your AC, with just one Powerwall, in an off-grid/outage scenario.

A single Powerwall can supply 30A. That's it. The only way to increase your amperage is to add more Powerwalls.

Some AC compressors can require more than 100A (!) or more to start. It's a specification that can be found on your compressor called LRA, short for Locked Rotor Amps. So when your compressor tries to start, it will try to draw 100A (or more), and your lone Powerwall will give up and shutdown, and now your entire house is down hard.

So, check your AC compressor's LRA! If the LRA is low, like 20A or so, you're (probably barely) OK. Otherwise, there are several choices:

1. Add more Powerwalls (thereby increasing the max amperage your system can deliver).
2. Exclude your AC compressor from your backed up loads. This means you won't have any air conditioning during an outage. But, you won't overload and shutdown your system either.
3. Replace your AC compressor with a more modern compressor with a low LRA.
4. Get a "Soft Start" capacitor for your compressor. These will store hundreds of amps in advance, so that when your compressor starts, it will draw that huge surge of power from the capacitor and not your Powerwall.
5. Do nothing and drink heavily.

Me? I have two Powerwalls and a hog of a compressor (160 LRA) with a Soft Start. Starts with no problems whatsoever.

Fruitcake

My AC's LRA is 79. I have checked with Tesla, are they doing whole house backup for my 1 PW+. They confirmed it. I also heard that PW+ has soft start built in, I could be wrong.

I will have to run test when everything is set up to see if the AC starts. I know running AC off on one PW+ won't last long. I will turn off AC when there's a blackout and run whole house fan instead.

 

[slcasner]

So you just have normal blade disconnect(s)?

None of them, either. On my old PV system installed in 2000 I had a blade disconnect, but that was removed along with the rest of that old PV system as the Solar Roof was installed.

Need pics of your new roof!

Yes, when I get a moment I plan to make a proper post with photos and some extra tidbits I expect will be of interest.

 

[holeydonut]

None of them, either. On my old PV system installed in 2000 I had a blade disconnect, but that was removed along with the rest of that old PV system as the Solar Roof was installed.

Yes, when I get a moment I plan to make a proper post with photos and some extra tidbits I expect will be of interest.

You don't have any blade disconnects? How did you pass inspection???

 

[slcasner]

You don't have any blade disconnects? How did you pass inspection???

Inspection has not happened yet. Maybe the rapid shutdown switch will be installed before that. As usual, it is hard to get information from Tesla about what will happen and when.

 

[oktane]

I’d upgrade the panel. EVs aren’t going anywhere and charging requirements will grow. 100A is nothing I’ve already maxed out my 400A panel.

You might be able to upgrade to 200A without running new cable or the transformer

 

[BGbreeder]

Or you can do what a local gas station does;

 

[KHYE]

Unfortunately, my project is still pending installation permit installation. I went back to review the SCE Interconnection Agreement that Tesla had me signed a while back. It stated that:

Actually, I'm getting a 10.2 kW system with 1 PW+ . Is this concern that I have to get Tesla to correct it?

 

[KHYE]

After almost 8 months long journey, I finally got PTO from SCE today and locked into NEM 2. I want to thank people on this forum who have guided and helped me along the way.

I didn't expect it would take this long as I spent lots of time and effort calling up Tesla, my county fire, building safety inspectors and SCE. It's Tesla who has caused the long timeline. I called Tesla so much that I can hum the "on hold" music in my dream!

*Got my roof, roof top AC and furnace replaced in Sept and Oct 2021

Sept 6, 2021 - Ordered system
Oct 13, 2021 - It took 5 long weeks to get first design, terrible
Oct to Nov 2021 - Going back and forth on PW location, requested on site assessment
Mid Nov 2021- Tesla submitted permit application
Jan 20, 2022 - Permit Issued, only then being told by Tesla that the earliest install date is in June 2022!
Feb 2022 - Kept calling Scheduling, got mid Apr 2022 install date, kept calling again and got mid Mar 2022 install date
* found out that the EMT of the trenching rusted out, got electrician to replace 3 days before Tesla installation
Mid Mar 2022 - Installation completed in 2 days, inspection completed in the following 2 weeks
Apr 13, 2022 - Paid full invoice the next day after passing inspection
Apr 14, 2022 - Called Tesla to submit PTO the very next day after payment.
Apr 15, 2022 - SCE confirmed PTO application. Of course, Tesla didn't update the correct panel size and system size in the inspection card. SCE caught this and rejected the application.
Apr 19, 2022 - Contacted Tesla permit and inspection coordinators, they fixed the issue and resubmit PTO application
Apr 26, 2022 - SCE approved PTO. Called Tesla to remove self consumption mode, I turned on "export to grid" and it works.