Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Arizona Powerwall Installs

This site may earn commission on affiliate links.
How long did it take them from the time you gave Tesla the go ahead?
Tesla told me they were waiting for SRP approval. Called them a couple days ago and they said no application for me. Emailed Tesla and now said they made an error and are on track now. So far not very impressed.

I ordered on May 2. We went back and forth a bit about adding 12 vs 24 panels, settled on 12 panels around mid-May. So about 2 months from final approval to install. Most of that time was waiting for Phoenix permits and APS approval.
 
Wow @JayClark thanks for that incredible reply! We're looking at an 8kw system with 3 PW. Might end up a little close on cloudy days to get through peak, but when we replace our AC (next summer or two) it should reduce our usage a bit. In the meantime I can always schedule the upstairs AC off the last few hours of peak.

Are there any features to alert on a battery level, or do you basically have to constantly monitor it? Ideally I'd like to set something up where, if I'm down to 75% before 5pm alert, or 50% by 6pm, etc, it sends me a phone notification. Or even better, if those thresholds are reached, I could have it turn off my AC via my upstair thermostat or something
 
I have an 8kw system with 2 batteries 3000sqft home with 2,14 seer ac units. I will say it does get tight some days especially on days it gets over 110 degrees. I wish I would of gotten the 3rd powerwall, but do I really need it? Not really and it would be more so I don't have to check the app at around 7pm.

My batteries are fully charged around 1pm and solar covers everything until about 4pm.

If the temps stay around 105 then I really don't do much with the app and my temp in the house is 78 all day.

I do have some things I need to replace, so that will probably help. Electric hot water tank that is horrible and draws 5.8kw when it turns on. 2 old 14 seer heat pump units that draw 4.3kw each when on. I charge my S at night, so other than those 3 things list above my house runs less than 1kw with those items list above not running. If all those turn on at the same time, then yeah we might have some problems.

My electric bill was $70 last month and on track for $120 this month. I also have a demand manager if things get too high to turn off at 2.9kws, but it hasn't tripped anything since I've gotten batteries.
 
Sure my total usage:

Apr - May 2020 - 1650 kWh Off Peak, 178 kWh On Peak
May - June 2020 - 2091 kWh Off Peak, 241 kWh On Peak
Jun - July 2019 - 2931 kWh Off Peak, 289 kWh On Peak
Jul - Aug 2019 - 3164 kWh Off Peak, 306 kWh On Peak
Aug - Sept 2019 - 2716 kWh Off Peak, 218 kWh On Peak

I don’t have July 2020 bill yet, but I just checked the SRP bill projection and it is telling me $105 right now. Figure by the 23rd it will be around $120, last years at this same time was $138.

Keep in mind we don’t travel to work anymore, so our usage will be a lot lower this summer, regardless I keep our house at 78 even when we traveling or at work. I try not to ever change the thermostat in the summer. I like to think it helps with keeping the scorpions out :)

Just another bit of info - May - June 2020 - Net Energy usage was 902 kWh Off Peak, -44 kWh On Peak. I also has a $156 SRP credit from last year that made my last 2 bills free.

We are 2 adults living in the house and all laundry is done during the day, but not after 4pm. I’m also wearing a jacket right now because it’s chilly in the house, I guess because its only 107 outside.

Hope that helps, if you have more questions let me know.
 
  • Helpful
Reactions: viperscorpio
ah I meant your total peak/offpeak usage, including whatever you use from generation & powerwall (so I could see how much peak you're mitigating with solar + 2PW). Not sure if there's an easy way to see that in the tesla app or not (how much power your home used from all sources between 2-8p on a given day)

That said, it looks like between May-Sept, you still use about 8-10kWh during peak/day, so your peak demand charge could be 1+ kW depending on how evenly that's spread out throughout the 6 hour peak?
 
Essentially, I used 60-65kWh on-peak quite a few days last week, when it was > 110 out (and I think we accidentally did some laundry during peak too). If I have 40kWh in battery (3 PW), I'd need another 20-25 from a combination of my 8kW system, or reducing consumption (possibly turning off one of the a/c's the last few hours)

That said, most days when it wasn't 110+, my daily consumption during peak was 40-45kWh, so it seems like I'll just need to watch out for the 20ish 110+ days we get every year, and, once I get some new A/C and other improvements, my utilization should lower a bit and won't have to worry anymore.
 
Let me try this again from the Tesla App. It seems different than what I see on SRP.... The July data might be more confusing than its worth since its only 16 days of service.

Jun 2020 All Usage
Home Usage 2347 kWh
Solar Energy 1466 kWh
Powerwall 440 kWh
From Grid 1175 kWh
To Grid 251 kWh

Peek Usage
Home Usage 635 kWh
Solar Energy 428 kWh
Powerwall 328 kWh
From Grid 12.6 kWh
To Grid 84.6 kWh

Off-Peak Usage
Home Usage 1799 kWh
Solar Energy 1087 kWh
Powerwall 121 kWh
From Grid 1208 kWh
To Grid 170 kWh

July 2020 to July 16th 2020 Usage
Home Usage 1667 kWh
Solar Energy 724 kWh
Powerwall 214 kWh
From Grid 1060 kWh
To Grid 79 kWh

Peek Usage
Home Usage 391 kWh
Solar Energy 226 kWh
Powerwall 211 kWh
From Grid 3.2 kWh
To Grid 33.3 kWh

Off-Peak Usage
Home Usage 1363 kWh
Solar Energy 550 kWh
Powerwall 18.4 kWh
From Grid 1111 kWh
To Grid 65 kWh
 
  • Helpful
Reactions: viperscorpio
Yeah I think the Tesla app has some gaps...perhaps someone else might know why it is different because I hardly look at usage as it doesn’t match. I really only care about how much battery I have left and what my currently kWh discharge rate is.
 
Wow @JayClark thanks for that incredible reply! We're looking at an 8kw system with 3 PW. Might end up a little close on cloudy days to get through peak, but when we replace our AC (next summer or two) it should reduce our usage a bit. In the meantime I can always schedule the upstairs AC off the last few hours of peak.

Are there any features to alert on a battery level, or do you basically have to constantly monitor it? Ideally I'd like to set something up where, if I'm down to 75% before 5pm alert, or 50% by 6pm, etc, it sends me a phone notification. Or even better, if those thresholds are reached, I could have it turn off my AC via my upstair thermostat or something

I do exactly this this in regard to the SOC alerts. I'm not aware of any way to get the alerts with the native systems. But I use @Darwins Powerwall Manager app, installed in my smartthings hub. It authenticates with the Tesla cloud api, and can provide a %alert that I can set. But... the app can do all sorts of other useful things that allow me to not pay as much attention. Like automatically turning off devices during peaks periods or after a certain amount of use, like helping manage AC behavior during peaks, or even changing between balanced and cost-saving modes on certain days based on the SOC, which I do on weekdays. And it all works without any monitoring.

So basically I use the Powerwall Manager App to notify me when my SOC gets as low as 40% or high as 75% on my phone - so no need for me to go check. I think the Powerwall Manager app (as it comes out of the box) allows both the high or low alert, I've made a few of my own modifications to the app, so can't always remember what it does out of the box.

What I think is even more useful, is that during normal week days in preparation for my 2-8pm peak period, I use the Powerwall Manager app to put the powerwall into "cost-saving" to start the day. This has the effect of having all solar go to the PW to insure it gets charged to my target SOC as quickly as possible to insure I have enough to cover my peak usage.

Then I have the Powerwall Manager app set to change to "Balanced" mode when the PW SOC gets to my 75% target on weekdays, for instance. This has the effect of then allowing the Solar PV to power house first, and send any remaining solar to further top off the PW above 75% before my peak period - so at this point I'm selectively using my solar to offset some off-peak power once I know my peak period coverage needs can be met, because I don't want to ever have to use the PW to power off-peak usage, just doesn't make sense for me in my house with the SRP utility rate structure. On weeks where we're expecting lots of cloud days, I set that target to more like 90% before it changes to balanced mode. When the forecast changes, is about the only time I poke around manually to tweak my target SOC.

This way I can always insure the PW gets to a certain SOC before my peak period and once my needed SOC his achieved, and if I have the extra solar, I can start to allow it to power the house. This way I can also reduce round trip PW charge/discharge cycling losses by not constantly topping off the PW at 100%, instead powering the house with extra solar after 75%, and more slowing allowing the PW SOC to creep up after it hits my target. And at this point this all works without me doing any monitoring or taking any manual actions myself. Hopefully that makes sense.
 
Last edited:
Thanks again for the details!

I don't have smartthings or hubitat, but I did find that there's some API available to access locally on the powerwall gateway, so, being in the field, I'll try my limited programming experience to write my own alerting (and maybe tie into my thermostats). Plus, that way I can implement the changes right away, as opposed to the delays that can sometimes be an hour or longer when making changes via Tesla's app
 
  • Like
Reactions: JayClark
Thanks again for the details!

I don't have smartthings or hubitat, but I did find that there's some API available to access locally on the powerwall gateway, so, being in the field, I'll try my limited programming experience to write my own alerting (and maybe tie into my thermostats). Plus, that way I can implement the changes right away, as opposed to the delays that can sometimes be an hour or longer when making changes via Tesla's app

Interestingly, for some time now, on my system, changes have been activating usually within a few minutes. At least I can see it change mode nearly instantly... but sometimes it can take a bit longer to fully 'activate' into the new mode if the system needs to warm the batteries if they've been idle for a while. But during the day, when the batteries are either charging from solar, or powering the house, changes occur and are active with minutes.
 
Thanks again for the details!

I don't have smartthings or hubitat, but I did find that there's some API available to access locally on the powerwall gateway, so, being in the field, I'll try my limited programming experience to write my own alerting (and maybe tie into my thermostats). Plus, that way I can implement the changes right away, as opposed to the delays that can sometimes be an hour or longer when making changes via Tesla's app

I change my mode (from self powered to backup only) manually, quite often, and with only a very very few exceptions, the change is reflected within a minute, usually less. Of note, I have my gateway connected via ethernet cable, and am not depending on wifi. Some of the things I have read here intimate that those on using wifi only with the gateway may have more trouble with this.

Note: By "quite often" I mean change modes manually at least every couple of days, but usually more like once a day or so, micromanaging it manually when I know I want to run the AC for a couple hours or something. The micromanaging is by choice, as I am aware I could likely do what I am doing manually by getting a smartthings hub and darwins app but for now I get too much satisfaction out of watching the electrons flow to automate it.
 
Just got my purchase agreement, and it looks like they're attempting to charge sales tax on the powerwall portion of the purchase. I thought powerwalls/batteries were exempt from AZ state sales tax? Anyone else have insight/experience on that?

Thanks!

I looked it up and it seems that batteries are not listed in the renewable energy sales tax exemption, so I think I may have been mistaken, and that I do in fact have to pay taxes on the powerwalls.

Another question - do you guys have the PWs installed in your garage? how are they holding up in the heat? Thanks!
 
Another question - do you guys have the PWs installed in your garage? how are they holding up in the heat? Thanks!

I have my powerwalls installed in my garage and they are doing fine in the heat. The powerwalls actively cool themselves, so heat shouldn’t be a problem. However, one thing I will note that I did not expect was that my four powerwalls noticeably raised the temperature in my garage, so that is definitely something to consider if you are thinking about a garage install.

I am currently operating my system off grid, until I get my official PTO, so the powerwalls are being exercised... they charge during the day and discharge at night and I’m sure that’s adding to the amount of heat they are generating. Because I have no TOU rate and my utility offers 1:1 net metering, once I get my PTO I will switch to backup only mode and I suspect that when the powerwalls aren’t working they will generate significantly less heat.
 
I have my powerwalls installed in my garage and they are doing fine in the heat. The powerwalls actively cool themselves, so heat shouldn’t be a problem. However, one thing I will note that I did not expect was that my four powerwalls noticeably raised the temperature in my garage, so that is definitely something to consider if you are thinking about a garage install.

I am currently operating my system off grid, until I get my official PTO, so the powerwalls are being exercised... they charge during the day and discharge at night and I’m sure that’s adding to the amount of heat they are generating. Because I have no TOU rate and my utility offers 1:1 net metering, once I get my PTO I will switch to backup only mode and I suspect that when the powerwalls aren’t working they will generate significantly less heat.

How long have you been basically off grid at this point?