Power Wall - No Solar Option

[KerrySkates]

Tesla Power Wall collects energy from solar panels to be used as desired in attempt to avoid pulling from the grid. That’s awesome, but I was thinking there is another option that could make Power Walls useful for some people who don’t have solar power (yet).

Where I live there is a program for reducing the cost per kWh for EV charging during “off hours.” I have to have a dedicated meter to qualify, but it’s there. Other places don’t require the dedicated meter.

In either case, where these programs exist, it would be cool if I could store energy into Power Wall during those off hours to be used at my leisure. I could use to save money on car charging during normal hours or to power the house during an outage.

While this idea might be good for customers and Tesla Power Wall sales, it could have an adverse affect by discouraging electric companies from offering these programs due to increased usage during those off hours.

Thoughts?

Is the point moot and this is already an option that I am just unaware of?

 

[power.saver]

Tesla Power Wall collects energy from solar panels to be used as desired in attempt to avoid pulling from the grid. That’s awesome, but I was thinking there is another option that could make Power Walls useful for some people who don’t have solar power (yet).

Where I live there is a program for reducing the cost per kWh for EV charging during “off hours.” I have to have a dedicated meter to qualify, but it’s there. Other places don’t require the dedicated meter.

In either case, where these programs exist, it would be cool if I could store energy into Power Wall during those off hours to be used at my leisure. I could use to save money on car charging during normal hours or to power the house during an outage.

While this idea might be good for customers and Tesla Power Wall sales, it could have an adverse affect by discouraging electric companies from offering these programs due to increased usage during those off hours.

Thoughts?

Is the point moot and this is already an option that I am just unaware of?

That option is available. There are a few members that have posted here with Powerwalls and no solar.

 

[Matt-FL]

To fully charge an EV, you'll need to factor in a car battery size versus the Powerwall. A typical Tesla car battery is 55kWh -> 100kWh. A Powerwall is rated at 13.5kWh. In order to charge an S3 base model (55kWh) by 50%, you'd need at least two Powerwalls. Four for a long range vehicle. In my opinion, you'd be better off using a time-controlled car charger that will automate charging during off-peak hours.

 

[KerrySkates]

To fully charge an EV, you'll need to factor in a car battery size versus the Powerwall. A typical Tesla car battery is 55kWh -> 100kWh. A Powerwall is rated at 13.5kWh. In order to charge an S3 base model (55kWh) by 50%, you'd need at least two Powerwalls. Four for a long range vehicle. In my opinion, you'd be better off using a time-controlled car charger that will automate charging during off-peak hours.

That all makes sense.

26kWh off of 2 Power Walls would save me a fairly significant amount of money vs charging at the normal rate. We’re talking $0.02/kWh ($0.52 total) vs $0.17/kWh ($4.42 total).

Now… would that be worth the cost of the installation of the power walls over time?
\_(ツ)_/¯
I haven’t done the math.

The idea would be that the power wall could be used for other home energy savings throughout the day more than for charging the car.

 

[h2ofun]

That all makes sense.

26kWh off of 2 Power Walls would save me a fairly significant amount of money vs charging at the normal rate. We’re talking $0.02/kWh ($0.52 total) vs $0.17/kWh ($4.42 total).

Now… would that be worth the cost of the installation of the power walls over time?
\_(ツ)_/¯
I haven’t done the math.

The idea would be that the power wall could be used for other home energy savings throughout the day more than for charging the car.

IMO, and I have 7, no way to PW's pay themselves back. Put in tons of solar. Since I have them, I charge the PW's in the morning. I then use the solar to charge my EV during the afternoon. Then once charged, the solar goes back to PGE.

 

[jjrandorin]

26kWh off of 2 Power Walls would save me a fairly significant amount of money vs charging at the normal rate

Now… would that be worth the cost of the installation of the power walls over time?
\_(ツ)_/¯
I haven’t done the math.

2 powerwalls installed is going to cost you more than $20,000, parts and labor. How long will that take you to break even, with charging at off peak and putting it back in the car during peak time. Dont forget about the roughly 10% round trip losses from storing the power in the powerwall and pulling it back out.

The delta between your off peak and peak is not big enough for this to make sense. with even rough math, if you saved $4 a day, every day, thats $1460 a year. Its going to cost more than 20k for 2 powerwalls to be installed (probably somewhere between 21-22k. Lets call it 20k to make it a round number. You are looking at 13 years before you even break even, on a product with a 10 year warranty.

it wont magically break in 10 years but you would need it to run for 13 years before you even got close to getting your money back.

powerwalls without solar only make sense in places with a very large delta between peak and off peak, and the ability to use just the energy in the powerwalls during peak time.

 

[h2ofun]

2 powerwalls installed is going to cost you more than $20,000, parts and labor. How long will that take you to break even, with charging at off peak and putting it back in the car during peak time. Dont forget about the roughly 10% round trip losses from storing the power in the powerwall and pulling it back out.

The delta between your off peak and peak is not big enough for this to make sense. with even rough math, if you saved $4 a day, every day, thats $1460 a year. Its going to cost more than 20k for 2 powerwalls to be installed (probably somewhere between 21-22k. Lets call it 20k to make it a round number. You are looking at 13 years before you even break even, on a product with a 10 year warranty.

it wont magically break in 10 years but you would need it to run for 13 years before you even got close to getting your money back.

powerwalls without solar only make sense in places with a very large delta between peak and off peak, and the ability to use just the energy in the powerwalls during peak time.

Have you ever seen a place where the delta between peak and off peak would ever make PW's only worth considering?

 

[jjrandorin]

I havent really studied it so I dont know, but my opinion is that unless someone is getting powerwalls (or other batteries) for free, or almost free (due to some subsidy or someone gifting them etc) the math wont make sense even in places with high delta's like CA.

Thats just a guess, and predicated on someone wanting a break even during the warranty period.

 

[bart513]

I have 3 PW's installed via the old referral system. I don't want to install solar yet as the roof will be replaced in about 3-5 years.
Any creative ideas how to keep the PW's charged during a power outage? They seem to power the house for about 18 hours during an outage.
Thanks in advance!

 

[Matt-FL]

Without solar, you'd need something like this, and a bunch of red bulls.

 

[bart513]

I guess that could take the place of my Peloton!!

 

[charlesj]

Without solar, you'd need something like this, and a bunch of red bulls.


View attachment 1057865

I guess that could take the place of my Peloton!!

At 20W, how long will it take? May need all family members pedaling.