Tesla Announces Powerwall 3 "DC Expansion"

[GateFather]

Tesla releases more details on Powerwall 3, confirms cheaper stack coming

Tesla has released more details about Powerwall 3, its new generation home energy storage system, and there’s some more good...

electrek.co

This is awful or great timing for me depending on how you look at it. I was just about to sign paperwork for a 23.49kW Panel system with 2x PW+ and 2x PW2 + 5.7kW inverter added to get to 20.9kW AC output. They told me they cannot use PW3 even if I wanted to downgrade to 2 because my utility considers all possible inverter AC output in their max number and their limit is 21. This is true even if the inverters are derated/disabled:

"Hi Michael, this is ..... with Tesla. That is correct. Due to the utility restriction, all the Powerwalls will be the Powerwall 2, and two of the four will be the Powerwall 2+ (includes an inverter). Our Design and Engineering Team did confirm that this will offer a whole home backup solution, meaning that all of your electrical appliances can be supported. If we were to change your project to include just two Powerwalls, the Powerwall 3 would still not be eligible because it would still surpass the utility AC limit."​

I asked about whether there would be a discount since I would be technically receiving older hardware. His answer:

"Regarding the pricing, it is the same for the Powerwall 2 and Powerwall 3."​

After this texting earlier, I saw the article above and asked him if there was a way to make it work with the PW3 DC Expansion. No answer yet. I'm thinking it might make most sense for me to stall or eventually cancel the process and likely lose my $100 deposit for now and then pick it back up once the DC Expansion versions are approved. However, I have a feeling I am going to be told that still, PW3 won't work for me due to the size of my solar system and the needs of inverters.

 

[CrazyRabbit]

Inflation…. Take the pw2’s now.

 

[GateFather]

Inflation…. Take the pw2’s now.

What do you mean?

 

[jgleigh]

Besides the LFP chemistry, why do you think 2 PW+ and 2 PW2 won't meet your needs?

 

[GateFather]

Besides the LFP chemistry, why do you think 2 PW+ and 2 PW2 won't meet your needs?

Other than the chemistry, there’s also considerably more equipment and a bigger overall footprint that the equipment will take up on the side of my house. It’s not that big of a deal since I’ll likely just plant some shrubbery/trees in front and out a bit to hide it. Also the 4x Powerwall 2s will output max combined 20kW where the 1Pw3 and 3 DC Expansion would output a combined 46kw. Not sure how big of a deal that is though since most of the time the power walls will simply power the home overnight which is just heater/AC and appliance loads like refrigerators (kitchen+garage+mini fridge+wine fridge).

 

[jgleigh]

A PW3 and 3 DC expanders will only output 11.5 kW. The DC expanders don't increase the continuous power output, only the stored energy.

2 PW+ and 2 PW2 will output 25.2 kW (on-grid) or 29.2 kW (off-grid) with full sun or 21.6 kW (on-grid) or 24 kW (off-grid) with no sun.

PW+ max continuous numbers:

 

[GregBallantyne]

If the PW2's meet your goals, and the PW3 w/expansion units doesn't exceed those goals fairly significantly, then time's a wastin. This whole thing is gonna take longer than it should, and probably longer than you think, so get to it.
I had the same (or similar, PW3 was just out) discussion a bit more than a year ago, reached the right conclusion, and am very glad I did so.... it still took 10 months longer than I thought going in. Panels take less time than Solar Roof, but more time is lost due to other reasons.

 

[GateFather]

If the PW2's meet your goals, and the PW3 w/expansion units doesn't exceed those goals fairly significantly, then time's a wastin. This whole thing is gonna take longer than it should, and probably longer than you think, so get to it.
I had the same (or similar, PW3 was just out) discussion a bit more than a year ago, reached the right conclusion, and am very glad I did so.... it still took 10 months longer than I thought going in. Panels take less time than Solar Roof, but more time is lost due to other reasons.

Yeah after meeting with my project advisor yesterday, I realized there is just no path to me getting PW3 due to my utility, not Tesla. The PW2s will work, I just liked that the PW3 had a smaller footprint and are LFP which is better battery chemistry. My advisor would not confirm the battery chemistry even though I told him that Tesla announced it. He said we don’t specify the chemistry of our batteries and anything you see online is not from Tesla. Hard to refute since the video supposedly saying it was LFP from Tesla was taken down. Likely because Tesla didn’t want that wide-spread.


I already signed all the docs and approved design. Now waiting for them to send me the liability insurance naming my HOA as additionally insured and the license so I can submit the architectural control application to the HOA. Coincidentally, I’ve been the VP on the board of directors for my HOA up until a week ago when my term ended (thank goodness), but not great timing for me to submit this because now I’m at the mercy of the new boards approval timeline. After that it’s permits, then utility approval, then install. Project advisor let me know he expects install around mid-June, then township approval within a week, then utility to install new meter and approve commissioning in 6-8 weeks after that.

 

[GregBallantyne]

In my case, it was that last grid operator dependent series of actions that stretched into 3 months. Seems like every step of the way you are waiting in another backlogged line.... but operation of a great system made the frustrations fade quickly.

 

[GWord]

Yeah after meeting with my project advisor yesterday, I realized there is just no path to me getting PW3 due to my utility, not Tesla. The PW2s will work, I just liked that the PW3 had a smaller footprint and are LFP which is better battery chemistry. My advisor would not confirm the battery chemistry even though I told him that Tesla announced it. He said we don’t specify the chemistry of our batteries and anything you see online is not from Tesla. Hard to refute since the video supposedly saying it was LFP from Tesla was taken down. Likely because Tesla didn’t want that wide-spread.


I already signed all the docs and approved design. Now waiting for them to send me the liability insurance naming my HOA as additionally insured and the license so I can submit the architectural control application to the HOA. Coincidentally, I’ve been the VP on the board of directors for my HOA up until a week ago when my term ended (thank goodness), but not great timing for me to submit this because now I’m at the mercy of the new boards approval timeline. After that it’s permits, then utility approval, then install. Project advisor let me know he expects install around mid-June, then township approval within a week, then utility to install new meter and approve commissioning in 6-8 weeks after that.

A PW2 based system has some advantages over PW3 that can make it a compelling option for some people. In particular, parallel inverters and battery banks make it more fault tolerant with (potentially) higher output per installed kWh (compared to PW3 w/ DC expansion). PW3’s chemistry is super compelling but with that said, I don’t think degradation has been a deal breaker for PW2 users overall, and there’s a pretty robust warranty.

 

[GateFather]

A PW2 based system has some advantages over PW3 that can make it a compelling option for some people. In particular, parallel inverters and battery banks make it more fault tolerant with (potentially) higher output per installed kWh (compared to PW3 w/ DC expansion). PW3’s chemistry is super compelling but with that said, I don’t think degradation has been a deal breaker for PW2 users overall, and there’s a pretty robust warranty.

Thanks. Can you elaborate a bit on what you mean with parallel inverters and battery banks? How does that make it have higher output per installed kWh? Just because more inverters are needed per kWh of stored energy? So in my case I’ll have the 2x 7.6kwh AC inverters that are part of (albeit separate units) the 2x Powerwall+ and a third that is 5.7kwH to bring the total to 20.9 since my utility limits total AC output to 21kwh. So are you saying if any one of the 3 fail the other two can continue on and provide their summer AC output?

 

[GWord]

Thanks. Can you elaborate a bit on what you mean with parallel inverters and battery banks? How does that make it have higher output per installed kWh? Just because more inverters are needed per kWh of stored energy? So in my case I’ll have the 2x 7.6kwh AC inverters that are part of (albeit separate units) the 2x Powerwall+ and a third that is 5.7kwH to bring the total to 20.9 since my utility limits total AC output to 21kwh. So are you saying if any one of the 3 fail the other two can continue on and provide their summer AC output?

That is correct. Each PW2 battery has its own inverter and can discharge up to its own limit. Additionally, each PW2+ has its own solar inverter and can invert the panel strings tied into it, regardless of the state of any other one.

In a PW3 based system with additional DC packs, one gets higher storage capacity but constant output. The advantage is presumably cost and reduced complexity.

 

[GateFather]

That is correct. Each PW2 battery has its own inverter and can discharge up to its own limit. Additionally, each PW2+ has its own solar inverter and can invert the panel strings tied into it, regardless of the state of any other one.

In a PW3 based system with additional DC packs, one gets higher storage capacity but constant output. The advantage is presumably cost and reduced complexity.

In my case the two Powerwall + will have their 7.6kw inverter but the extra 5.7 inverter is only I guess for both of the other 2 Powerwall 2s to charge from?

 

[GWord]

In my case the two Powerwall + will have their 7.6kw inverter but the extra 5.7 inverter is only I guess for both of the other 2 Powerwall 2s to charge from?

Or the battery portion of the PW2+. The Gateway will track solar production from all your inverters and manage PW charging based on total available power (along with your time of use settings.) Power from any inverter can be used by any PW2/2+

 

[GregBallantyne]

Or the battery portion of the PW2+. The Gateway will track solar production from all your inverters and manage PW charging based on total available power (along with your time of use settings.) Power from any inverter can be used by any PW2/2+

Interesting. This is an advantage for a multiple PW2 installation, that supports my overall conclusion I reached last year. I concluded that there are real advantages for PW3 if your installation will be limited to one (and possibly 2 PW) but in a multiple PW installation with a whole home backup config PW2 was more suitable.

 

[GateFather]

Interesting. This is an advantage for a multiple PW2 installation, that supports my overall conclusion I reached last year. I concluded that there are real advantages for PW3 if your installation will be limited to one (and possibly 2 PW) but in a multiple PW installation with a whole home backup config PW2 was more suitable.

After everything I’ve learned and that’s been said here, I completely agree, even with the addition of the DC expansion for PW3. My advisor noted the same. He said majority of systems have 1 Powerwall and 1PW2 was not enough to handle initial startup v requirements for AC Units, for example. PW3 was really meant for 1-2 PW installs max and it’s my opinion that even with DC Expansion, Whole home backup solutions with large solar panel installs will still require PW2, at least until electrical utilizes stop their anti-competitive practices.

 

[GregBallantyne]

After everything I’ve learned and that’s been said here, I completely agree, even with the addition of the DC expansion for PW3. My advisor noted the same. He said majority of systems have 1 Powerwall and 1PW2 was not enough to handle initial startup v requirements for AC Units, for example. PW3 was really meant for 1-2 PW installs max and it’s my opinion that even with DC Expansion, Whole home backup solutions with large solar panel installs will still require PW2, at least until electrical utilizes stop their anti-competitive practices.

I was a bit bothered by the "perhaps old and obsolete" thing last year when I had this discussion with my installer, but have been very well satisfied with my multiple PW2 installation operation. My goals going in are being met or exceeded. My config is whole house backup in which all power sources including grid go to Gateway, and Gateway feeds existing load center, and decides where solar production goes - enabling the battery charging choice GWord highlighted.
Maybe the best use for the PW3 expansion units is the single PW3 installation that gets subsequent expansion upgrades. One thing I've noticed is that no matter how great your system is, adding more battery capacity always has its attractions.... I sure would like to enhance mine with another 1-3 PW2's.....

 

[GateFather]

I was a bit bothered by the "perhaps old and obsolete" thing last year when I had this discussion with my installer, but have been very well satisfied with my multiple PW2 installation operation. My goals going in are being met or exceeded. My config is whole house backup in which all power sources including grid go to Gateway, and Gateway feeds existing load center, and decides where solar production goes - enabling the battery charging choice GWord highlighted.
Maybe the best use for the PW3 expansion units is the single PW3 installation that gets subsequent expansion upgrades. One thing I've noticed is that no matter how great your system is, adding more battery capacity always has its attractions.... I sure would like to enhance mine with another 1-3 PW2's.....

Looks like my system will be similar to yours. I'm very curious to see how 23.49 DC into 20.9 AC feeding my home and 4x Powerwalls will look with different configurations of when/where/how power is distributed. My plan to remove some of our unused refrigerators and other unnecessary electrical loads should help us be green most of the year since the system I am getting is spec'd to include them.

 

[Jeremy3292]

That is correct. Each PW2 battery has its own inverter and can discharge up to its own limit. Additionally, each PW2+ has its own solar inverter and can invert the panel strings tied into it, regardless of the state of any other one.

This is interesting. I was in the same position as OP last year (awaiting install now, check signature). My DC solar size is 9.315 kW with three Powerwalls. Tesla opted to give me two PW+ (and one PW2) each with a 7.6 kW inverter, for 15.2 kW total AC inverter size instead of just one PW+ (and two PW2) and 7.6 kW inverter size. I suspected at the time this was due to the seemingly large failure rate of the inverters e.g. overheating. My theory was less heat and less time at the max 7.6 kW AC rating would reduce their failure rates. Large DC to AC panel to inverter ratios seemed to be the newest fad/trend over the past years, but they may be a fading fad now.

So if my understanding is correct, what you’re saying makes sense and in theory if one inverter failed, the 2nd PW+ inverter could handle my solar system while waiting for the other inverter to be replaced, no?

 

[Jeremy3292]

Interesting. This is an advantage for a multiple PW2 installation, that supports my overall conclusion I reached last year. I concluded that there are real advantages for PW3 if your installation will be limited to one (and possibly 2 PW) but in a multiple PW installation with a whole home backup config PW2 was more suitable.

I came to this conclusion as well. If you’re only getting one PW, then PW3 is definitely a game changer over the PW2/+ and a really nice thing to have. 11.5 kW peak output and 185 LRA is really, really good for only one PW. But since I’m getting three PWs like others here, the peak kW output and LRA ratings don’t matter bc three PWs combined can handle just about anything.