Powering my house with POWERWALL and WITHOUT solar

Powering my house with POWERWALL and WITHOUT solar

Installing solar is not cost effective, but I like the idea of powering my house using TESLA POWERWALLS, and having the batteries recharged from the grid during the evening when electricity is cheaper. Is there an option to install POWERWALLS, have them power the entire house during the day and then recharge at night from the grid?

snovakov | 2017年11月3日

At the present time, Tesla app cannot be used to program when the PW2 will charge and discharge. They claim that it is coming soon. Three different reps from SC/Tesla could not define "soon". So, my PW2s are sitting in simple backup mode until "soon" happens. Hope this helps. I, too, bought them to be able to charge them at night and discharge during expensive electricity hours.

zubinanary | 2017年11月7日

The feature is coming by Dec 31st according to Tesla. I am doing exactly what you say, but I have to do it manually right now until the software can automate it.

I flip the breaker at 6am and run my house off the batter. At 11pm I flip the breaker and let the battery, my Model S and my Model X charge.

I've been doing this since Sept 13 when I had my Quantity 2 Powerwall 2 installed. To date, 879 hours of total battery use.

Note: The feature you speak of is called "Time of Use Load Shifting", whereby you charge at the cheapest rates and use it at the more expensive rates.

In my case, I'm in PG&E, Northern California near the Tesla Factory. Our cheapest rate is $0.12/kw, and our most expensive is $0.46/kw, so Time of Use Load Shifting can be a huge savings... even more so if you got the SGIP rebate for the Powerwall 2 install...

My total cost was $13800 for Quantity 2 Powerwall 2, + gateway + installation. SGIP cash back rebate from SGIP will be $9200, so my out of pocket costs will be $4500, and I can re-coup that pretty quickly over 3 years at the cheaper $0.21/kw.

sashton | 2017年11月8日

Sadly in the UK there is no state incentive. The cheapest rate here is £0.074/kWh and the average day rate is £0.17/kWh. Counting conversion losses and amortising (5%pa) the capital cost results in a payback period of about 14 years.
I only justify it as part of a solar installation and even then it is touch and go whether it will wipe its feet before the warranty on the battery expires.
...but its been a great toy :)

Ross1 | 2017年11月9日

Possibly the most savings you can make off the system, is to wait a few years for price decrease of Powerwall. At least $1000 a year I guess.

Moradbenayed | 2017年11月14日

I have ordered solar panels and 2 batteries from Tesla on Sep 30, unfortunately, I had the most horrific experience ever. It has been 6 weeks, and still no designs. First, Tesla told me that the surveyor did a bad job and had to redo it, then for 6 times, I got bad jobs from designers, and after 4 iterations, I still have nothing. The designers are sooooo bad that even my 10 years old daughter could have done a better job: 1st rendering had wrong number of panels, i.e. 6 instead of 9 - 2nd rendering had no panels at all - 3rd rendering had panels that are not centered - 4th rendering had panels layed out vertically instead of horizontall. It has been 10 days that I am waiting for 5th iteration and still nothing. Sales are not responding. Customer support takes 48 hours to respond. Escalations to CS manager on 2 occasions result in promises of "manager will call you back later today" but I get no calls. PLEASE HELP!!!!! By the way, Tesla is also now pulling back from commitment to deliver batteries by end of year as promised when contract was signed. Now they are saying "best effort", however, given they track record of operational incompetence, I can only think that they will not deliver. I have given them a deadline to commit or let me purchase my batteries from another supplier, but PLEASE DO NOT LEAVE ME HANGING IN THE AIR BECAUSE OF YOUR INCOMPETENCE!!! Fix your problems Tesla!!! My account is moradbenayed @ gmail . com / dorraf @ yahoo . fr. My poor sales lady who seems frustrated by powerless is Erikka. The personal concierge who takes 48 hours to respond is Taylor Gurney. The CS manager who does not call back is Allen Compton. PLEASE FIX YOUR ISSUES. I have an order for a Tesla car, and I am really concerned about quality, service and ability to deliver.

Peter_clark | 2017年12月7日

zubinanary - have you heard from TESLA regarding the inspection for the SGIP and check for the program? I have 2 Powerwall 2 units installed 11/29 and have been doing manual TOD load shifting for just one week. My concern is that the setting on my TESLA app and the SGIP will not be correct so that I get the rebate check. So far I don't mind the flipping of the switch every AM / PM, but would love it to be available on the tesla APP.

I'm in So Cal, FYI, on so cal edison.

salcaide | 2017年12月12日

I posted this once before on another thread (wish I could search the forum effectively), but if we can manipulate the CT's (Current transformers, those little circular things that they clamp around the wires in a few places to measure current flow), then we can force the Powerwall to do what we want. All you need to do is trick the PW into thinking there is tons of solar power coming into the system (it will charge), or that there is power being drawn from the grid (it will discharge). One solution would be to simply disconnect the CT's and use some kind of circuit to send signals to the PW. Another way (viable in my opinion) would be to wrap a thin wire many times around (through) the CT's, and then run a tiny current through them from some automation (smartthings & switched outlet) as needed. This would fake the system into thinking there is lots of current going through that wire. Lots of different ways to play this. But it gets around any of Tesla's legal issues that might be preventing them from releasing the scheduling software. Anyone here capable of something like this?

erikpk | 2017年12月17日

@zubinanary (hopefully you or someone can explain). I too am in northern CA (Auburn area), PGE is utility supplier and on TOU. It sounds like you are flipping the breaker and the grid is charging your PW2 at night. Is that correct? Do you have solar? If I can bypass the PW2 from only charging on the solar that would be awesome. Just had my PW and solar system turned on last week so super jazzed to take full advantage! Thanks for the help

Ross1 | 2017年12月17日

My electrician is most definite that it wont work, powering battery up at night, due to the % inefficiencies with every switching.
Is he right?

jonc | 2017年12月19日

I think your electrician may be wrong. Even with the inefficiency. I'm on TOU as well. My off peak price is $.12/kWh, peak is $.48/kwh. That is a huge difference. I estimated that my 2 PW2's will pay for themselves (after rebate) in 2.5 years.

I Wanna Go Fast | 2017年12月21日

"Round Trip Efficiency: 89% for AC Powerwall, 92% for DC Powerwall"
For me, Powerwall 2 will save around $480/year after losses, charging at night (off-peak) an discharging by day.
Installing now with incentives, awaiting the firmware update to enable load-shifting time of use.

ali.abbani.1 | 2018年10月25日

i am from Lebanon, middle east. we have suffer from electricity crisis here. because the electricity grid come for 4 hours. then it cut off for 4 hours. and that s how it work here with us. there is rationing of electricity. so i am wondering if i bought 1 or 2 powerwall to my house without solar panels. Then i will charge it when i have electricity for 4 hours. then when the electricity cut off i use the Powerwall2. what do you think!! it can work in this way???