Powerwall 2 install.

[cebury]

Why do I have to pay for it?

You aren't paying for anything. You are contributing your fair share.
From each according to his ability (to be taxed).

[max2k]

You aren't paying for anything. You are contributing your fair share.
From each according to his ability (to be taxed).

Now you're scaring me- I thought I left that place for good . That system (socialism) is not economically viable no matter who tried to make it work. Humanity must be insane to keep trying.

[max2k]

op used microinverters and AC coupled the battery, so no coordination between PV and the battery is required for load shifting. ...

How that is supposed to work without some 'energy governor': how battery AC would know it is supposed to handle house loads if PV is producing but its output is not enough? Or the opposite- it would need some current sensor on the grid side to determine direction of the power flow and make decision if it should let excess of PV energy to go to the grid or be consumed for charging battery.

[sensij]

How that is supposed to work without some 'energy governor': how battery AC would know it is supposed to handle house loads if PV is producing but its output is not enough? Or the opposite- it would need some current sensor on the grid side to determine direction of the power flow and make decision if it should let excess of PV energy to go to the grid or be consumed for charging battery.

Load shifting doesn't require the energy to come from PV, so the battery doesn't have to care *where* the energy is coming from, just *when* it is coming. The "backup" model requires more control than the load shifting model does, and adds a switch to disconnect from the grid. It looks like both models use CT's on the service panel feed to keep track of what is going on.

One case I don't understand with AC coupling a powerwall 2 to an Enphase PV system is when in backup mode (off grid), the battery is full, and PV potential exceeds the loads. What would force the PV system to throttle?

[SWFLA]

I would guess frequency curtailment that's how SMA does it.

[Sunking]

Now you're scaring me- I thought I left that place for good . That system (socialism) is not economically viable no matter who tried to make it work. Humanity must be insane to keep trying.

That is what Millennials are being taught in school today.

[jflorey2]

How that is supposed to work without some 'energy governor': how battery AC would know it is supposed to handle house loads if PV is producing but its output is not enough?

It doesn't. I talked to a Tesla rep about it and there is no regulation. Powerwall accepts energy until it can't any more; voltage rises and the microinverters (hopefully) trip off-line due to voltage out of range.

[sensij]

It doesn't. I talked to a Tesla rep about it and there is no regulation. Powerwall accepts energy until it can't any more; voltage rises and the microinverters (hopefully) trip off-line due to voltage out of range.

Answers my question!

[JSchnee21]

Just to ask, the OP, sriram97, why is he going with an Enphase solution versus SolarEdge? If the PowerWall 2 AC can communicate / coordinate with the StorEdge, wouldn't this be a better solution. The cost and performance should be pretty similar (or better) than an Enphase solution.

Still, we haven't really addressed the question as to whether or not only two PowerWall systems can carry his whole house (including HVAC). Nor have we found out whether he's getting the PowerWall's with or without backup.

[sriram97]

You are right I stand corrected.

Since the CA SGIP is a rebate you need to do the calculation as:
( 17k - 9,400 ) x 0.7 = $5,320

[sriram97]

No A/Cs in calculation. Yes backup is included. The enphase units allow me to monitor per panel performance. A central inverter was definitely less expensive

Just to ask, the OP, sriram97, why is he going with an Enphase solution versus SolarEdge? If the PowerWall 2 AC can communicate / coordinate with the StorEdge, wouldn't this be a better solution. The cost and performance should be pretty similar (or better) than an Enphase solution.

Still, we haven't really addressed the question as to whether or not only two PowerWall systems can carry his whole house (including HVAC). Nor have we found out whether he's getting the PowerWall's with or without backup.

[sriram97]

One moreninfo clarification. I may have misspoke the gateway is a separate line item charge of 700 included in the overall price.

Thank you, they have interesting component there called 'Energy Gateway' which I assume would be the 'brain' of the whole setup- did you get that installed as well and included in the cost above?

How much did PV part of the system cost for 7.4kW array? I understand the inverter is built in into PowerWall so that must have provided some savings on PV side of things.

[sriram97]

Sorry I was not aware that solar edge also made microinverters and assumed that you were asking about their central inverters. If you meant the microinverter, fwiw I was not aware of and did not evaluate solar edge microinverters as an option.

No A/Cs in calculation. Yes backup is included. The enphase units allow me to monitor per panel performance. A central inverter was definitely less expensive

[adoublee]

It doesn't. I talked to a Tesla rep about it and there is no regulation. Powerwall accepts energy until it can't any more; voltage rises and the microinverters (hopefully) trip off-line due to voltage out of range.

So Powerwall(s) have to be provided such that maximum solar current (inverter AC rated current) does not exceed battery current limits (assuming no load is present)? Other than that (and battery shutting itself and therefore the whole system down on low voltage when discharged) - no coordination between battery, solar, and load? I do like the idea of a whole whole house grid isolation switch (gateway) instead of a critical loads panel - then I can just manage the energy implications myself. That is a major benefit of the high power rating.

[sriram97]

Here's a description of the new app that's basically an update to the stock Tesla app. It seems to show the entire source and flow of power to the home and also apparently gives you alerts so in case of extended outages manual load shedding can be supported

https://www.google.com/amp/s/electrek.co/2017/04/20/tesla-powerwall-solar-app/amp/