Powerwall with solar = no grid charging
- Thread starter racpuc
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Ulmo
Active Member
@racpuc, I received a phone call before they installed the system where they specifically asked and confirmed how I would like to have it provisioned. It is my understanding that during that call they set my records for how they will direct the system. I believe there is flexibility in how they program the system to work, but it is a manually hard coded option on their end. You would be well to call them and ask them what the current manually hard coded operating modes are available and what you can choose from. While doing that, you can also ask as an aside what they think will be coming soon for software updates, but that's not something anybody should use up a lot of time for, since no one can predict the future 100%. Be ready with specific and simple explanations for what you think you're looking for.
In my case, Tesla offered exactly what I wanted for now as an option and I chose that, and it's working great. That happens to align with Elon's stated and advertised purpose of the batteries for the general case, i.e., shifting sun energy to darker times. What I knew wasn't immediately available are the more complex smart grid operations that should be coming over the next years. I really hope that future new programming from all entities is comprehensive and soon. It's still a developing area (one which should have been done decades ago but is being done now).
In my case, Tesla offered exactly what I wanted for now as an option and I chose that, and it's working great. That happens to align with Elon's stated and advertised purpose of the batteries for the general case, i.e., shifting sun energy to darker times. What I knew wasn't immediately available are the more complex smart grid operations that should be coming over the next years. I really hope that future new programming from all entities is comprehensive and soon. It's still a developing area (one which should have been done decades ago but is being done now).
MZP95
Member
Were you eligible for 30% federal tax credit for your powerwall though you are also charging from grid. What I heard is atleast 75% powerwall charging should be from Solar to be eligible for 30% tax credit.
Sorry to ask questions in old thread. However, I have exact issue. I have existing solar system and want to add powerwall 2. However, the representative I talked to clearly, specifically told me that if I have solar system, I can't charge the powerwall from the grid. I simply don't get the reason. Basically, my solar system generation can't sustain all the house usage, especially in winter. I have to charge from grid at night time and use them at peak rate hours. Also, my solar system use micro inverter and feed the AC back. Why can't powerwall pretend there is no solar system and charge from grid.
GenSao
Member
@sink , Per Tesla FAQ:
To qualify for the 30% Federal ITC, Tesla prohibits use of the grid in normal operations* to charge the Powerwall. Tesla assumes users will claim the ITC. Furthermore, utilities typically discourage the use of batteries to make money off of Time of Use (TOU) rate arbitrage (load shifting and storing solar is ok). There is no way around this (for now). Perhaps a future software update will fix this (after 5 years of ITC vesting).
*There are additional modes that will consume grid energy (even if solar is installed). Storm Watch will charge the Powerwall when there is a poteintal storm based on National Weather Service alerts. Powerwall uses Preconditioning to counteract the effect of low temperatures on batteries.
75% threshold is for commercial applications. It has to be 100% for ITC on residential applications.
This means some people (with small, inefficient PV systems) may not have a fully charged battery during the day in the winter months.
This is common. My Powerwall system bounces off the Reserve daily in the Winter due to generation less than the Peak period usage.
It's a mysterious Tesla-only limitation. You could move CTs around to make Tesla think Grid = Solar, at your own responsibility.
Hi there. I've been reading the threads and I find myself in the same predicament. I have an existing solar system and I was looking into getting the Tesla powerwall. but now my fear is that if I get to power wall I'll actually may increase my yearly true because I will not be able to leverage my time of use. Looking at it at a economical view I'm starting to think perhaps it does not make any sense for me. Am I assuming correctly?
I think having the battery would almost be like going back to net metering in a sentence. A kilowatt for a kilowatt however you would get stuck paying to charge the car at night.
My biggest reason for looking into power wall was due to power going out 5 to 10 days a year. But at this point I'm starting to think a generator for the few days the power's out would be a more economical approach. Thanks for your time.
I think having the battery would almost be like going back to net metering in a sentence. A kilowatt for a kilowatt however you would get stuck paying to charge the car at night.
My biggest reason for looking into power wall was due to power going out 5 to 10 days a year. But at this point I'm starting to think a generator for the few days the power's out would be a more economical approach. Thanks for your time.
You didn't say where you are located or what your utility billing policies and rates are. Whether you can save any money using Time Based Control with solar on a Powerwall depends completely on how your utility does billing. We can't help you decide without that information.
OppositeLock
Member
I'm a new Powerwall 2 user, and I have a tiny solar system - only enough roof exposed to sun for 2.4kW, and partly shaded too. I wish I found this thread before getting the Powerwall! As it stands, it's sitting at the backup limit, and not charging at all. I guess that will change when the days get longer and there's less rain - I'm in the bay area of CA, so guessing I'll get above 50% sometime in April 
My solar system only made about 1kWh/day the last week.
My solar system only made about 1kWh/day the last week.I also have a small solar system, not even double your size, but I have two Powerwalls. Last Winter, basically mid-November to mid-February, I was bouncing off the Reserve every day. This year is pretty much the same. While I would love to be able to shift Off-Peak energy from the grid so that I did not consume any Peak power in the Winter, that's just not how it works and I have to accept that I have to pay more during these Winter months. More because I don't generate enough and more because there is consumption during Peak hours. C'est La Vie.I'm a new Powerwall 2 user, and I have a tiny solar system - only enough roof exposed to sun for 2.4kW, and partly shaded too. I wish I found this thread before getting the Powerwall! As it stands, it's sitting at the backup limit, and not charging at all. I guess that will change when the days get longer and there's less rain - I'm in the bay area of CA, so guessing I'll get above 50% sometime in April
bmah
Moderator, Model S/X, California Forums
Has anyone heard anything official from Tesla about this? Is the Powerwall locked to only charging via solar for the life of the serial number, or at some point will Tesla unlock them and allow grid charging if you buy them in conjunction with solar? Seems crazy that in 10 years they'd still be locked to solar only.
zanary
Active Member
All we know is that if you take the ITC credit, then it's a 5 year limitation that Tesla activates in their config on your Powerwall Gateway. What happens after 5 years, we can only speculate.
I've had my Powerwalls since October 10, 2017 (when I got my official PTO from PG&E), so I'll know for sure once I reach my 5 year mark in a few more years.
Where did you find that policy? I've been asking Tesla, and this is the closest I've gotten to an answer:
"When Powerwalls are installed with PV systems, the PV system is its charging source, and will not be set up to pull and store energy from the grid. We can also reach out to your designer for a more detailed explanation if you would like."
Tesla can only install a small solar system, but it takes two powerwalls to really provide backup power. It seems like most of the value would come from doing peak shaving, or demand shifting along with the solar. Thanks for the info!
"When Powerwalls are installed with PV systems, the PV system is its charging source, and will not be set up to pull and store energy from the grid. We can also reach out to your designer for a more detailed explanation if you would like."
Tesla can only install a small solar system, but it takes two powerwalls to really provide backup power. It seems like most of the value would come from doing peak shaving, or demand shifting along with the solar. Thanks for the info!
There is another thread here with a similar discussion:
Charge PW from Grid
I'd also like to know for sure whether it is Tesla or the utility that is imposing the requirement. I'm not taking the ITC so that shouldn't be the issue.
Charge PW from Grid
I'd also like to know for sure whether it is Tesla or the utility that is imposing the requirement. I'm not taking the ITC so that shouldn't be the issue.
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