Considering powerwall

[zƬesla]

There was one person who ended up in that situation. I forget the posters name at this point but I think @DrSmile pointed to them in your other thread. Their specific issue was, they were getting solar and powerwalls, and having two different vendors install them (one for solar, and one for powerwalls) but both were new installs.

New PowerWall install woes

I'm the OP for above thread. Still working with Tesla certified installer to resolve the issues.

 

[Vines]

To clarify some things about this issue. Yes, I am the main tech resource to design these Powerwall systems at the company I work for. We do mostly bigger systems with 3 Powerwalls and more.

1. The reason why there is so much confusion is because of how new this all is. Many installers are not at the cutting edge, just responsive. In a few more years this will settle down. Also, anyone who is getting the system piece by piece is doing themselves a disservice unless the same company does both. For the reasons pointed out in the other thread, you want the systems to work together seamlessly, and under 1 installer so there's no case where one says the other is responsible.

2. Older PV inverters (before newer firmware allowing partial PV curtailment) are either on or off. In a grid outage the PW shift the microgrid frequency to about 65 hz when they are getting close to full, or when the home loads plus charge rate <PV Generation. You cannot produce more power than you consume or the rest becomes heat very rapidly.

In the case of overproduction of PV, the PW sends an "Out of range" grid signal to the inverters, and the inverters recognize dirty microgrid power and shut off. If you have 20 kW PV and 2 PW, you must consume with house loads the difference between the 10 kW charge rate that the PW can accept, and the balance of the PV generation. At the point after you turn on enough loads, the Powerwalls would recognize this charge rate is something they can accept and start charging. Some older inverters may have an alternate firmware to make this partial curtailment work better.

3. Newer PV installations with partial curtailment inverters, can work with the Powerwall and understand when the battery is getting close to a full charge. When the PW gets near 90% charge it will start frequency shifting to about 60.5-62.5 hz, which will initiate a partial curtailment of the PV. The PV will ramp its production down, as the Powerwall approaches full, and totally shut off when the PW cannot accept more power.

 

[gpez]

To clarify some things about this issue. Yes, I am the main tech resource to design these Powerwall systems at the company I work for. We do mostly bigger systems with 3 Powerwalls and more.

1. The reason why there is so much confusion is because of how new this all is. Many installers are not at the cutting edge, just responsive. In a few more years this will settle down. Also, anyone who is getting the system piece by piece is doing themselves a disservice unless the same company does both. For the reasons pointed out in the other thread, you want the systems to work together seamlessly, and under 1 installer so there's no case where one says the other is responsible.

2. Older PV inverters (before newer firmware allowing partial PV curtailment) are either on or off. In a grid outage the PW shift the microgrid frequency to about 65 hz when they are getting close to full, or when the home loads plus charge rate <PV Generation. You cannot produce more power than you consume or the rest becomes heat very rapidly.

In the case of overproduction of PV, the PW sends an "Out of range" grid signal to the inverters, and the inverters recognize dirty microgrid power and shut off. If you have 20 kW PV and 2 PW, you must consume with house loads the difference between the 10 kW charge rate that the PW can accept, and the balance of the PV generation. At the point after you turn on enough loads, the Powerwalls would recognize this charge rate is something they can accept and start charging. Some older inverters may have an alternate firmware to make this partial curtailment work better.

3. Newer PV installations with partial curtailment inverters, can work with the Powerwall and understand when the battery is getting close to a full charge. When the PW gets near 90% charge it will start frequency shifting to about 60.5-62.5 hz, which will initiate a partial curtailment of the PV. The PV will ramp its production down, as the Powerwall approaches full, and totally shut off when the PW cannot accept more power.

May I add one here?

Not only is the tech new it's constantly changing as the Powerwall has the ability to remotely update software out of the hands of the customer. This means new features can roll out but also creates pockets of different experiences which adds to the confusion. It also means that problems that were happening before may have been fixed, making personal anecdotes about experiences with issues in the past may not be applicable today.

 

[Willy3]

To clarify some things about this issue. Yes, I am the main tech resource to design these Powerwall systems at the company I work for. We do mostly bigger systems with 3 Powerwalls and more.

1. The reason why there is so much confusion is because of how new this all is. Many installers are not at the cutting edge, just responsive. In a few more years this will settle down. Also, anyone who is getting the system piece by piece is doing themselves a disservice unless the same company does both. For the reasons pointed out in the other thread, you want the systems to work together seamlessly, and under 1 installer so there's no case where one says the other is responsible.

2. Older PV inverters (before newer firmware allowing partial PV curtailment) are either on or off. In a grid outage the PW shift the microgrid frequency to about 65 hz when they are getting close to full, or when the home loads plus charge rate <PV Generation. You cannot produce more power than you consume or the rest becomes heat very rapidly.

In the case of overproduction of PV, the PW sends an "Out of range" grid signal to the inverters, and the inverters recognize dirty microgrid power and shut off. If you have 20 kW PV and 2 PW, you must consume with house loads the difference between the 10 kW charge rate that the PW can accept, and the balance of the PV generation. At the point after you turn on enough loads, the Powerwalls would recognize this charge rate is something they can accept and start charging. Some older inverters may have an alternate firmware to make this partial curtailment work better.

3. Newer PV installations with partial curtailment inverters, can work with the Powerwall and understand when the battery is getting close to a full charge. When the PW gets near 90% charge it will start frequency shifting to about 60.5-62.5 hz, which will initiate a partial curtailment of the PV. The PV will ramp its production down, as the Powerwall approaches full, and totally shut off when the PW cannot accept more power.

Outstanding, thank you