New PV+Powerwall2 setup

[AndreSF]

Very recently got my 5.85Kw PV system + Powerwall2 activated in San Francisco, CA, so wanted to share my experience and ask a few questions.

The entire system was designed/installed by Tesla. I think I've initially engaged them probably in Aug 2017, signed contract in Nov. System was installed on 01/09/18 - 01/10/18, and just activated on 05/01/18. Tesla had to come back a few times to make corrections after the initial inspection, follow up inspections took time, PG&E took their sweet time... But finally, have everything on and functioning almost to my satisfaction.
Initially, Powerwall was not taking a charge from PV, so it took a call to Tesla to get that sorted out.

At this time I have one issue that I'm waiting to hear on from Tesla, so was hoping someone has had similar experience and can share any info:

- By the initial design, a few of my circuits were left in the main panel and are supposed to be powered only by the grid. High output kitchen appliances (2) and a 30Amp circuit that I use to charge my Model S
- The rest of the circuits are "powered by" backup load center, per my understanding and are backed up by powerwall in the event of an outage
- Powerwall is configured for "self-powered" mode
- What is happening now though is that those high output circuits in the main panel are still drawing power from powerwall. For example, when scheduled car charging kicks in at 11PM, it draws 5kw from powerwall and 1 from the grid. Obviously, this is not my desired setup, as car charging depletes reserves of the powerwall rather quickly, leaving the house to draw power from the grid, until powerewall is recharged from PV system

I wonder if anyone has any insight on this issue.

 

[Tam]

...a few of my circuits were left in the main panel and are supposed to be powered only by the grid...

Do you have what before and after main panel pictures look like?

Your current picture has 2 vertically grey panels. Which is which?

It doesn't sound like your main panel is wired for direct grid only and to bypass PowerWall.

It looks like you are missing "Essential Loads" panel for your desired design.

What you have right now is "Whole Home Backup" (without Essential Loads panel) as pictured below:

 

[AndreSF]

Do you have what before and after main panel pictures look like?

Your current picture has 2 vertically grey panels. Which is which?

It doesn't sound like your main panel is wired for direct grid only and to bypass PowerWall.

I took that pic before all boxes were labeled by the installers...

The main panel should be wired to bypass powerwall, based on the original design (that was the main purpose of having these circuits in a separate panel). The main panel is on the left in the pic, at this point it contains the 3 circuits in question, main breaker and 80amp gateway breaker. The second box from the left is the gateway, the third one - backup load center where all remaining house breakers are located now (aka essential loads).

 

[AndreSF]

There is also a sub-panel that is not in the pic, but it's off of the backup load center (aka essential loads)

 

[cwied]

Note that the location of the gateway controls which loads are powered when the grid is down. When the grid is up, the powerwall determines how much power to export based on the measurements from the current transformers (CTs) hooked to the gateway (actually the Neurio inside the gateway box).

It sounds like the house load the gateway is seeing includes all the circuits on the main panel. This means if it's trying to offset house load, it will feed everything.

Since electrons are electrons, it doesn't really matter which circuit you're feeding, though. If you don't want the Powerwall to discharge, set the backup reserve higher than the current charge.

Long-term, you'll be able to use the advanced, time-based control to make sure that the Powerwall doesn't discharge during the off-peak rate period when you're charging your EV.

 

[Tam]

...the pic...

Thanks for labeling the picture which makes it much clearer!

I look up:

Powerwall Modes of Operation with Solar

"Self-powered: Use stored solar to power your home after the sun goes down

Discharge priority: Net Usage."

So it is not about the wrong wirings that I thought. It's about its definition.

 

[AndreSF]

Ok, thanks for the feedback... I hope Tesla can sort this out with future FW updates, as if the system works as intended, that is not what they sold me initially. And really don't know how useful such self-powered setup can be for anyone with an EV that is not on a separate meter as the house, as the car would suck up all the collected energy by PV very quickly. Even with my usual commute charging, I routinely pull in 10 - 15Kwh at night, not to mention any decent trip, which I usually end with only 10 - 20% remaining in the EV battery.
I mean, we still generate quite a bit of clean energy, but I would definitely hold off on powerewall if I knew this would be the outcome. With the recent update of rates for GoSolarSF/CleanPowerSF program, I charge from the grid at 2.8cents per kwh, so the powerwall really was interesting to me from being more independent with normal house loads.
I can't really switch to backup mode, as the main reason for getting the powerwall was to offset its cost by California self-gen rebate.

 

[cwied]

I guess what I would say is it doesn't make a difference whether the power from the grid goes to the EV and your powerwall powers your essential loads or if the power from the grid goes to your essential loads and the power from the powerwall goes to your EV. All that matters in the end is that you discharged a certain amount of energy and consumed a certain amount of energy from the grid. Just set your backup reserve % so the amount that you discharge each day is the amount that your essential loads use, and the end result is the same. The only difference is the time period during which the Powerwall discharged.

The other way to solve your "problem" would be to re-arrange the CTs so they only see the essential loads. That would also prevent the batteries from offsetting the other loads, but I think that's less ideal, because if you actually do have enough energy stored to offset your high-power loads you might want to have the option to do so at some point (for example if the utility were paying you to reduce your consumption).

Edit: just to clarify - I'm not suggesting you switch to backup-only mode - just change your backup reserve % to achieve the desired results.

 

[AndreSF]

I guess what I would say is it doesn't make a difference whether the power from the grid goes to the EV and your powerwall powers your essential loads or if the power from the grid goes to your essential loads and the power from the powerwall goes to your EV. All that matters in the end is that you discharged a certain amount of energy and consumed a certain amount of energy from the grid. Just set your backup reserve % so the amount that you discharge each day is the amount that your essential loads use, and the end result is the same. The only difference is the time period during which the Powerwall discharged.

The other way to solve your "problem" would be to re-arrange the CTs so they only see the essential loads. That would also prevent the batteries from offsetting the other loads, but I think that's less ideal, because if you actually do have enough energy stored to offset your high-power loads you might want to have the option to do so at some point (for example if the utility were paying you to reduce your consumption).

Edit: just to clarify - I'm not suggesting you switch to backup-only mode - just change your backup reserve % to achieve the desired results.

Well, it actually does make a difference to me, as rates are different at night and in the morning when we would use the powerall to feed the house electrical needs, until there is enough PV energy (on cloudy days it could be a while). In addition, I was planning on moving more loads to the electrical power source, such as water heater, for example, so having a reserve in powerewall definitely makes a lot of sense in that respect.
I can play with backup reserve for sure though...

 

[Brovane]

- What is happening now though is that those high output circuits in the main panel are still drawing power from powerwall. For example, when scheduled car charging kicks in at 11PM, it draws 5kw from powerwall and 1 from the grid. Obviously, this is not my desired setup, as car charging depletes reserves of the powerwall rather quickly, leaving the house to draw power from the grid, until powerewall is recharged from PV system

I wonder if anyone has any insight on this issue.

Have you tried playing around with the reserve setting for Power Outages? Without TOU function yet on the Tesla App I have used it to crudely minimize power draw after 10pm.

 

[AndreSF]

Have you tried playing around with the reserve setting for Power Outages? Without TOU function yet on the Tesla App I have used it to crudely minimize power draw after 10pm.

It was suggested earlier as well in this thread, so I've bumped up the reserve to 50% from initial 30%. I know what it does, so it's not exactly what I had in mind. I guess it is what it is for now until Tesla opens up more advanced settings.

 

[AndreSF]

Thanks, everyone for your replies! It all makes sense, I just wish Tesla would outline the functionality better during the pre-sales and design process. I'm a "Tesla cool-aid drinker", so it's easier for me to overlook some of the rough edges in the process/with these new products and, at times, relatively poor project management. Other folks might not be as understanding...

 

[Az_Rael]

I can't really switch to backup mode, as the main reason for getting the powerwall was to offset its cost by California self-gen rebate.

Have you heard anything from Tesla about which step you will be in?

 

[AndreSF]

Have you heard anything from Tesla about which step you will be in?

Nope... they are not that good at outgoing communications (have to ping them about everything). I was hoping to make step 2, but now dunno, and will be happy to be a part of step 3 at this point...
Did get a reply today from "district energy partner" contact about self-referral though, and I did indeed "refer myself", so expecting that rebate, plus $500 from Tesla, as I've used them to install the system. WIll be happy to use my "Tesla money" to pay for upcoming car service.

 

[Az_Rael]

Nope... they are not that good at outgoing communications (have to ping them about everything). I was hoping to make step 2, but now dunno, and will be happy to be a part of step 3 at this point...
Did get a reply today from "district energy partner" contact about self-referral though, and I did indeed "refer myself", so expecting that rebate, plus $500 from Tesla, as I've used them to install the system. WIll be happy to use my "Tesla money" to pay for upcoming car service.

Yeah, they are terrible at communication. I was advertised Step 3 when I signed in Sept 2017. I called last week because Step 3 for SCE is opening Monday and I wanted to see if they knew where I was on the list. They said they were starting with March/April 2017 contracts for Step 3. So now I am not so sure I will make Step 3.

 

[AndreSF]

Yeah, they are terrible at communication. I was advertised Step 3 when I signed in Sept 2017. I called last week because Step 3 for SCE is opening Monday and I wanted to see if they knew where I was on the list. They said they were starting with March/April 2017 contracts for Step 3. So now I am not so sure I will make Step 3.

Oh, then I'm in the similar boat, I guess... Signed contract early Nov '17.

 

[AndreSF]

I'm also up for CleanPowerSF rebate, but don't even know if I want to ask Tesla the status again on that, as they have been extremely slow to respond on most communications.
The sales person (sorry, energy advisor, was super quick...before the sale

 

[Az_Rael]

before the sale

Yeah, that was my experience too (our system was installed in April, but I am still awaiting SCE approval). I find if I just call the main customer service number and talk to whomever I get, I get a better response. My sales advisors have been AWOL since my system install.

 

[AndreSF]

Tesla claimed it was PG&E slowness with our project, but who really knows... PG&E did simplify the final approval process to some degree, which allowed my project to move forward. I did complain to Tesla though, and they sent me a check (did not ask for it!) for one loan payment of my system.
They did a "boo-boo" with the panels install, so had to correct after city inspection and that took multiple visits and looong time. Overall, as I have stated in the initial post, from actual install date to the activation date it took almost 4 months (!!!!).

Overall, I'm glad the system is running now, although not positive I would do it again. CleanPowerSF program, for example, has now pretty reasonable rates (much better than PG&E) for 100% renewable energy sources, so that is an alternative for many ppl in SF IMO.

Good luck with your project, and hopefully the sun will soon be doing some work for you!