Solar inverted needed with Powerwall 2.0?

[thelastdeadmouse]

I don't have a good financial case for getting a Powerwall when I have solar installed. I was wondering if a solar to grid inverter is still needed if you have the Powerwall 2.0 or if the panels use the Powerwall's inverter? If it does that reduces the marginal cost of the powerwall by 1-2k.

 

[GJ79]

following.....

 

[ecarfan]

The page at Tesla Powerwall states the Powerwall 2.0 has an "integrated inverter". Here is text from that page:

Quote: "Powerwall uses an internal inverter to convert DC energy to the AC energy required for your home, lowering cost and complexity."

At a minimum that must mean that DC energy stored in the Powerwall is converted to AC for home use. Whether it also means that the internal inverter can convert the DC solar panel output into AC for use in your home, bypassing the Powerwall battery, I do not know.

 

[Sodamo]

How does the current PW charge from the PV? A direct connection from the PV to PW or you have to supply something in between?

 

[Utahken]

How does the current PW charge from the PV? A direct connection from the PV to PW or you have to supply something in between?

The pv goes to the solaredge inverter and it charges the powerwall as needed from the DC side 350V to 450V.

 

[electracity]

The "AC Powerwall" is the one that is probably intended for existing solar installations.

It is unclear what is needed for a new solar install. Powerwall 1.0 uses power optimizers on the panels to stabilize voltage. Tesla hasn't said how this works with 2.0. The lack of detail suggests that the new power wall may be further away than a couple months.

 

[doctorwho]

I've got a bizarre situation here in Australia, we had a 4.5kW system installed 2 years ago and have moved it to our new house that we've just completed on the same property. It's counted as a new installation now (same panels and inverter) but the compliance regulations have changed and the existing inverter is now no longer compliant. No problem if it were still on the old house but we can't get a bi-directional meter without a compliance certificate and so 'miss out' on the pitiful 5c per kWh feed in tariff. If the Powerwall2 comes with it's own inverter that I can DC couple to the panels it'll solve my problem as I won't need to buy an additional inverter.

 

[Jason S]

I've got a bizarre situation here in Australia, we had a 4.5kW system installed 2 years ago and have moved it to our new house that we've just completed on the same property. It's counted as a new installation now (same panels and inverter) but the compliance regulations have changed and the existing inverter is now no longer compliant. No problem if it were still on the old house but we can't get a bi-directional meter without a compliance certificate and so 'miss out' on the pitiful 5c per kWh feed in tariff. If the Powerwall2 comes with it's own inverter that I can DC couple to the panels it'll solve my problem as I won't need to buy an additional inverter.

I think the idea with the Powerwall is to not bother with the 5c per kWh feed in and instead use that electricity yourself timeshifted (to riff on your avatar).

BUT

I can't imagine they designed it for one direction only, so I expect they can dump the excess to the grid. Only way to find out for real is to contact your local dealer.

 

[doctorwho]

i need the bi-directional meter for this. The standard feed-in tarrif here is pathetic, they'll pay me 5c a kWh for my power and sell it back to me for 30c per kWh!

 

[electracity]

I've got a bizarre situation here in Australia, we had a 4.5kW system installed 2 years ago and have moved it to our new house that we've just completed on the same property. It's counted as a new installation now (same panels and inverter) but the compliance regulations have changed and the existing inverter is now no longer compliant. No problem if it were still on the old house but we can't get a bi-directional meter without a compliance certificate and so 'miss out' on the pitiful 5c per kWh feed in tariff. If the Powerwall2 comes with it's own inverter that I can DC couple to the panels it'll solve my problem as I won't need to buy an additional inverter.

DC coupled must be on their roadmap, but it would not be surprising if it was delivered later. But as Jason points out, you would not have much to export with 14 kWh of storage.

 

[aesculus]

I would definitely like to see a PV panel > battery > car all on a DC bus, and only go to AC when I wanted to spill into the house or send it back onto the grid for credit etc. A energy control system could decide when and how I would do that in real-time. I suspect this will come in PW 3.0.

If I was building a new house I would even wire the DC bus into the home for mobile device charging and LED lighting. Even today I wonder how hard it would be to take all the 15 amp circuits that are dedicated to lighting and put them onto a separate DC panel. I am sure that there is probably some code somewhere that says NO, because they are stapled together with the 20 amp circuits on a wall stud yada yada.

 

[Nevetsyad]

I would definitely like to see a PV panel > battery > car all on a DC bus, and only go to AC when I wanted to spill into the house or send it back onto the grid for credit etc. A energy control system could decide when and how I would do that in real-time. I suspect this will come in PW 3.0.

If I was building a new house I would even wire the DC bus into the home for mobile device charging and LED lighting. Even today I wonder how hard it would be to take all the 15 amp circuits that are dedicated to lighting and put them onto a separate DC panel. I am sure that there is probably some code somewhere that says NO, because they are stapled together with the 20 amp circuits on a wall stud yada yada.

Don't forget, to get your 1440 watt 12 amp, 120 volt AC, you'll need a 12 volt DC, 120 amp connection. That's going to be some HUGE gauge wiring to handle that. This is why, unfortunately, AC is king for anything but short or low power runs.

 

[tchaimd]

Hi, there,

It appears that for new installs, a separate inverter is indeed required, as per a local installer TreeHouse in Austin. Here is a direct quote from them per an email inquiry that I sent them recently:

Yes, Powerwall V2 is $5,500! This is the cost of the battery only and does not include installation, monitoring, or back-up equipment.

The Powerwall 2 comes in an AC-coupled and DC-coupled option:

The AC-coupled option is designed to be installed with pre-existing solar arrays. This is the only option that includes an inverter. This is because the inverter is to only provide for the battery's needs and not for those of the solar array.

The DC-coupled option is designed to be installed with new solar arrays using a separate "hybrid inverter" that serves as the inverter for both your battery and the solar array. This hybrid inverter is what is included in your quote as "StorEdge Inverter". The size of the proposed solar array, 12.06kW, would require a second, small inverter as the StorEdge Inverter does not have the capacity to accommodate the entire needs of a 12.06kW system. This inverter is included in your quote as SE3800.

 

[Nevetsyad]

Your array is too large for one inverter is what they're saying. They stated that the AC version includes an an inverter right in the above text.

 

[Gwgan]

Does this blurb from SolarEdge mean existing StorEdge inverters are not compatible with PW2?
StorEdge™ Solution with Backup | SolarEdge

Coming Soon- SolarEdge High Power StorEdge Inverter with additional battery support
The High Power StorEdge inverter will support Tesla's Powerwall 2 and LG's RESU10H* batteries, as well as two Tesla Powerwall 1 (type E) or Powerwall 2 batteries for high power. The new batteries will only be compatible with SolarEdge’s High Power StorEdge inverter (part number SE7600A-USS2xxxxxx) and not with earlier versions of the StorEdge inverter.

A free inverter firmware upgrade is required to support the high power batteries and configurations. Information about the firmware version can be found in the product release notes and will be available, along with the firmware upgrade file, in the StorEdge Firmware Upgrade page.

More details will be available in February 2017.

 

[Gwgan]

Answering my own question; got a call back from SolarEdge Sales, they did think that new hardware would be required but have just learned that current inverters will be compatible with PW2. Details to follow.

 

[MP3Mike]

The data sheets, attached, give some details of how PW2 get installed.

 

[Cosmacelf]

Thanks for the spec sheets, but it doesn't answer the question of how it provide backup power during a power outage and/or work with the solar inverter during power outage (ideally you want the solar panels to power a critical load panel, and then the battery take over if the panels don't generate enough power).

 

[ecarfan]

ideally you want the solar panels to power a critical load panel, and then the battery take over if the panels don't generate enough power

My Solar/Powerwall 1 system does that.

 

[Cosmacelf]

Yes, but how does the AC coupled Powerwall 2 do that?