Tesla Wants to Build a Battery for Your House

[kwilcox]

Well, I can't speak to the home battery (who can given the dearth of detailed specs), but I do know that the 85KWh battery in the model S is designed to cycle far more than 50 times per year over its 8 year replacement guarantee.

[Sunking]

Does it make a lot of difference if the 500 cycles are over a short time vs a long time (i.e. 10 years)? I guess I'm asking what is the interaction among age, number of cycles, and DOD?

Ian that is the million dollar question as each is a trade-off. Batteries have calendar whether they are used or not. They have cycle life vs DOD and they all over lap. A good example assume you have a battery, any battery with a Calendar life of say 7 years, 5000 cycles to 50% DOD, or 2000 cycles to 80% DOD. Capacity say 1 Kwh to make math easy. What do you do with it? .

Knee jerk reaction is 5000 cycles 50% DOD. But you would be wrong. In 7 years is only about 1600 to 1800 cycles and you are dead. Calendar life bit you in the butt. In that time you only get 800 to 900 Kwh out of it. Take it to 80% and you get the same amount of cycles before the Calendar clock runs out. Difference is you now get 1280 to 1140 Kwh out of it or 21% more energy over the same time period.

No where is what is really fish about Tesla claims. At 10 Kwh 500 cycles. At 7 Kwh over 3000 cycles. That might not sound fish to you, but stinks to me. Reason is you look at any of the Lithium chemistry they all have roughly the same ratios. Example say you get 1000 cycles at 100% DOD, at 50% DOD you only gain 50% or 1500 cycles. So if they claim 500 cycles at 100% DOD, one expects 750 to 800 cycles at 70% DOD not 3000 plus. 1000 cycles or double would be a quantum leap. 3000 is make believe.

It is not just me giving Musk the evil eye, it is the whole battery world calling it BS.

[pleppik]

Well, it appears that Tesla will (only) have an electrician install the battery. I can't speculate much more than that myself. Better to wait and see what empirical data comes from actual installations. I am intrigued however by the large number of utility scale orders.

It doesn't surprise me. Utilities have a huge gap between the cheapest and most expensive power they buy/generate. Customers pay something more like an average.

At the prices Tesla is offering, I expect the utilities will be installing these things all day long. They can save a bundle by charging the batteries from base generation and using the battery power instead of building peakers.

[Ian S]

That does not strike you as odd and smell fishy? I don't know of any battery chemistry, especially Lithium family that goes from 3000 cycles @ 70% DOD and drops all the way down to 500 cycles at 90-100% DOD. There are FLA batteries that have better performance curves.

Does it make a lot of difference if the 500 cycles are over a short time vs a long time (i.e. 10 years)? I guess I'm asking what is the interaction among age, number of cycles, and DOD?

[Sunking]

10 kwh low cycle, 7 kwh high cycle. Same batteries. Different setup option.

That does not strike you as odd and smell fishy? I don't know of any battery chemistry, especially Lithium family that goes from 3000 cycles @ 70% DOD and drops all the way down to 500 cycles at 90-100% DOD. There are FLA batteries that have better performance curves.

[Willy T]

I A 350V to 400V battery with 50 cycles a year is what is giving me pause. .

That must have come from Sun King.

Tesla, a world leader in the field of electric mobility, is an ideal partner on our way towards being able to use solar power twenty-four hours a day." The two companies have already been working together for some time in the automotive business area: Tesla uses Fronius welding systems for manufacturing its S and X models.

This sounds more realistic.

[Living Large]

Well, it appears that Tesla will (only) have an electrician install the battery. I can't speculate much more than that myself. Better to wait and see what empirical data comes from actual installations. I am intrigued however by the large number of utility scale orders.

Installation by an electrician, a drunk neighbor, Santa Claus. That isn't my problem. A 350V to 400V battery with 50 cycles a year is what is giving me pause. I don't go to church very often, so I'm not big on acts of faith.

[kwilcox]

Well, it appears that Tesla will (only) have an electrician install the battery. I can't speculate much more than that myself. Better to wait and see what empirical data comes from actual installations. I am intrigued however by the large number of utility scale orders.

[Living Large]

Not my statement, That's Elon Musk's statement. Of course it's not believable. After all, everything he's ever said has been unbelievable right? Paypal, SpaceX, Tesla, Solar City. All unbelievable....

I don't doubt someone placed orders.

What I don't understand is how the batteries for home use will be able to be used, as discussed above in this thread.

Heck, I could have ordered some and put them in my basement when delivered. Then what?

[kwilcox]

Not my statement, That's Elon Musk's statement. Of course it's not believable. After all, everything he's ever said has been unbelievable right? Paypal, SpaceX, Tesla, Solar City. All unbelievable....

[Sunking]

This just in:
Sold out in 6 days: 38,000 home batteries and 2,500 utility scale batteries have been ordered

What is funny is you believe it.

[SunEagle]

This just in:
Sold out in 6 days: 38,000 home batteries and 2,500 utility scale batteries have been ordered

Reminds me of the carpetbaggers selling snake oil treatments in the old western towns.

[kwilcox]

This just in:
Sold out in 6 days: 38,000 home batteries and 2,500 utility scale batteries have been ordered

[bberry]

Now it looks like the 7KWH battery isn't even being offered as a solar option. Solar City will only install the 10KWH "backup" battery with solar systems. So, the 7kwh system is only for time shifting grid power consumption.

People are still lining up to buy it.

"While storing residential power with the Powerwall is still more expensive than grid power, that doesn't mean people won't buy it."

-P.T. Barnum

It also looks like the 10kwh version is only rated at 50 cycles per year.

Bloomberg Tesla Powerwall article

10 kwh low cycle, 7 kwh high cycle. Same batteries. Different setup option.

2016
Solar Offgrid
7 kwh packs
Hawaii

They ain't doing off grid in Hawaii next year with weekly cycle packs, now are they?

[Sunking]

It also looks like the 10kwh version is only rated at 50 cycles per year.

Told you it was DOA didn't I? Whole 500 cycles POS battery for $7000.