Worth switching to net "time-of-use" metering for grid-tie solar system in NY (ConEd)

[nevetsyad]

It is not evident that the powerwall 2 has a DC to DC capability. Further the solaredge inverter is 98% efficient and likely the powerwall 2 inverter is close. The lose is in the chemical transition from electromechanical energy ( electricity ) to chemical stored energy in the battery and back. So you would have a smaller efficiency gain by using DC to DC vs AC to AC to DC .

BTW it is $1500 in parts to upgrade the SE7600-US to the storedge ( SE7600-USS) but even more to upgrade it to backup capable with the auto transformer, emergency panel and wiring, and consumption meter.


What you are talking about is a DC coupled solution with powerwall 1 vs an AC coupled solution with powerwall 2

I am not a big fan of AC coupled solutions of any type due to over complexity, multiple equipment manufacturers ( some do not support the solution), and excess wear to the equipment from the poor throttle ability of the designs.

DC coupled solutions are simpler, and much more easily controlled.

I believe it was said in the unveiling that they can be charged directly via DC, for slightly higher efficiency. The rumor is, the solar cells are going to push high voltage DC into the powerwall 2 and it's going to charge and do the inversion, no need for a dedicated solar inverter anymore! It's also the only way a grid tied setup could charge a powerwall, if the powerwall was completely discharged. Unless there's some "emergency jump start capacity" that lets you fire up the inverter using what's left of the battery when the sun comes up. That would be cool.

I'm hoping the $1,000 install for the powerwall covers the auto transformer and all with Tesla hardware. I'd just need to make my SE7600 able to put DC current into the battery, let it handle control of AC power in and out of the house. Who knows until the installer comes out and shows me options though.

True, more reason to do it in DC, if it doesn't cost thousands extra. But it's good to know the AC-DC-AC loss is single digit percentages, I thought it would be more. Thanks for that.

[ButchDeal]

I believe it was said in the unveiling that they can be charged directly via DC, for slightly higher efficiency. The rumor is, the solar cells are going to push high voltage DC into the powerwall 2 and it's going to charge and do the inversion, no need for a dedicated solar inverter anymore! It's also the only way a grid tied setup could charge a powerwall, if the powerwall was completely discharged. Unless there's some "emergency jump start capacity" that lets you fire up the inverter using what's left of the battery when the sun comes up. That would be cool.

I'm hoping the $1,000 install for the powerwall covers the auto transformer and all with Tesla hardware. I'd just need to make my SE7600 able to put DC current into the battery, let it handle control of AC power in and out of the house. Who knows until the installer comes out and shows me options though.

True, more reason to do it in DC, if it doesn't cost thousands extra. But it's good to know the AC-DC-AC loss is single digit percentages, I thought it would be more. Thanks for that.

What do you mean by dedicated solar inverter. Al DC coupled bimodal systems work with only one inverter and the powerwall 1 storedge solution only has one inverter.
The powerwall 2 is an AC coupled solution that was mentioned will work with most existing solar inverters.
You can charge the powerwall two via AC coupling from any solar inverter. Your statement about e only way to charge makes no since, even a DC coupled system will. Not start if the battery is dead. The emergency jump start is with a generator BTW.