Tesla Wants to Build a Battery for Your House

[Sunking]

I beg your pardon, this comes straight from the Tesla web site, your guessing again.


http://www.teslamotors.com/powerwall

I am typing slowly so you can understand and did not listen the first 50 times when it was announced.

Only difference between them is the firmware to restrict the DOD. Both are a 400 volt 25 AH battery (10 Kwh). Same cabinet, exact same dimensions, exact same weight, exact same battery, just different firmware in the code that restricts DOD.

[Willy T]

Beg your pardon but the 7 and 10 Kwh batteries are the exact same battery. The 50 cycles per year come straight from Tesla on the 10 Kwh battery which makes no sense at all. It is by no means inexpensive as Tesla has admitted no one can actually buy either battery for $3000 or $3500 dollars. More like $7000 if you buy it outright.

I beg your pardon, this comes straight from the Tesla web site, your guessing again, you have no clue of what one cooling system one may have over the other or what cells are used. I never said anything about cost, I could care less about what it costs.

Powerwall comes in 10 kWh weekly cycle and 7 kWh daily cycle models.

http://www.teslamotors.com/powerwall

[Sunking]

My understanding is that the batteries are targeted at two usage scenarios:

• they can charge using off-peak rates (hours surrounding midnight) and discharge during peak rates (waking hours) allowing customers to take better advantage of tiered rates.
• they can be used in conjunction with a solar array. Since peak home usage is generally during the time you cite and also in the morning (shown on Tesla's site and I can validate empirically based on my own TED5000 history), the battery can leverage a solar array to store energy during peak output times (usually around noon when sun energy is highest and overall energy use is negative) and release it during morning/evening hours.

Tell us what market that works in and why. It is easy as there is only one or two markets that fits. Couple of hints:

Left Coast
Neighbors will buy your battery
Fruits and Nutz

[Sunking]

Where did you get to the conclusion that 1hp=12,000 btu=1ton ?

1hp =745.6 watts
1 watt = 3.41 btu

745.6 x 3.41 = 2542.49 btu

1hp = 2542.49 btu.....not 12,000 btu or 1 ton.

You just walked into a movie at the conclusion and have no idea what happened. He was referring to Air Conditioning and Refrigeration in the early days when it did take 1 hp motor to turn a 1-ton compressor.

[Sunking]

Then you know the difference in buying a emergency back up and something your going to use daily to time and power shift.

Beg your pardon but the 7 and 10 Kwh batteries are the exact same battery. The 50 cycles per year come straight from Tesla on the 10 Kwh battery which makes no sense at all. It is by no means inexpensive as Tesla has admitted no one can actually buy either battery for $3000 or $3500 dollars. More like $7000 if you buy it outright.

[Willy T]

I guess I haven't been clear. I am OFF GRID. A backup for me is a requirement, not a waste.

This forum is not all about you, I didn't quote you. Once you get off grid you'll get a understanding of it all.

[Living Large]

It doesn't fit everyone, no one solution will.

1) Do you want a backup for GT solar other than a Generator ( y/n ) ?

2) Do you have TOU pricing of at least $.30 per kwh. ( y/n )

3) What is your reimbursement rate for excess kwh ?

4) Do you want seamless backup fiddle free ( y/n )?

All of the above have to be answered before it would be of any interest to most people. Some people could break even or make money ( very few ) Any back up is usually a loser, for most it would be a waste. Then this backup would only work short term and to be of any value you'd still have to have a generator to supplement it.

Personally, I wouldn't waste a penny on it.

I guess I haven't been clear. I am OFF GRID. A backup for me is a requirement, not a waste.

[kwilcox]

I still dont get the use, or market for this thing.

Most homes have peak useage, in the evenings, when the family is home. ( Lights on, TV on, oven on, etc..etc..)

So this thing charges during the day.

Wait... Peak POCO rates are during the day.... and cheapest at night.

So when exactly am I supposed to charge this thing, and use it.... to use it effectively??

I also need the device, a AC to DC rectifier to charge it, and a DC to AC inverter to use it, so I'm really buying 3 devices, plus losing efficiency at every conversion step.

I'm sticking with Solar....

My understanding is that the batteries are targeted at two usage scenarios:

• they can charge using off-peak rates (hours surrounding midnight) and discharge during peak rates (waking hours) allowing customers to take better advantage of tiered rates.
• they can be used in conjunction with a solar array. Since peak home usage is generally during the time you cite and also in the morning (shown on Tesla's site and I can validate empirically based on my own TED5000 history), the battery can leverage a solar array to store energy during peak output times (usually around noon when sun energy is highest and overall energy use is negative) and release it during morning/evening hours.

[Willy T]

It doesn't fit everyone, no one solution will.

1) Do you want a backup for GT solar other than a Generator ( y/n ) ?

2) Do you have TOU pricing of at least $.30 per kwh. ( y/n )

3) What is your reimbursement rate for excess kwh ?

4) Do you want seamless backup fiddle free ( y/n )?

All of the above have to be answered before it would be of any interest to most people. Some people could break even or make money ( very few ) Any back up is usually a loser, for most it would be a waste. Then this backup would only work short term and to be of any value you'd still have to have a generator to supplement it.

Personally, I wouldn't waste a penny on it.

[Living Large]

Two different products designed to do two different things, both are for a Grid Tied System.

So why would it give you pause because they offer it for someone that has no use for a daily cycle product ? Thats like being concerned about Ford Motor Co offering other trucks than pickup trucks.

I have no interest in a grid-tied system. End of story. I have my dad's vacuum tube collection - equally useful technology to me.

If I needed a pickup truck, I wouldn't buy a box truck or church van on a Ford chassis.

[Alisobob]

I still dont get the use, or market for this thing.

Most homes have peak useage, in the evenings, when the family is home. ( Lights on, TV on, oven on, etc..etc..)

So this thing charges during the day.

Wait... Peak POCO rates are during the day.... and cheapest at night.

So when exactly am I supposed to charge this thing, and use it.... to use it effectively??

I also need the device, a AC to DC rectifier to charge it, and a DC to AC inverter to use it, so I'm really buying 3 devices, plus losing efficiency at every conversion step.

I'm sticking with Solar....

[Willy T]

I haven't drank Kool-Aid in over 40 years.

The 50 cycles per year for the 10kwh Powerwall, 350V-400VDC comes from Tesla, not Sunking.

Then you know the difference in buying a emergency back up and something your going to use daily to time and power shift. Two different products designed to do two different things, both are for a Grid Tied System.

So why would it give you pause because they offer it for someone that has no use for a daily cycle product ? Thats like being concerned about Ford Motor Co offering other trucks than pickup trucks.

They don't hide the fact they have two different products with two different uses, nice to see some honesty.

Powerwall comes in 10 kWh weekly cycle and 7 kWh daily cycle models. Both are guaranteed for ten years and are sufficient to power most homes during peak evening hours. Multiple batteries may be installed together for homes with greater energy need, up to 90 kWh total for the 10 kWh battery and 63 kWh total for the 7 kWh battery.

[Living Large]

That must have come from Sun King. (50 cycles, 350-400V)

This sounds more realistic. (marketing talk)

I haven't drank Kool-Aid in over 40 years.

The 50 cycles per year for the 10kwh Powerwall, 350V-400VDC comes from Tesla, not Sunking.

[kwilcox]

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.

That's precisely why I'm intrigued because cheap storage will reduce demand charges for renewables. Autonomous grid based energy storage/delivery makes weather related peak generation calculations obsolete and delivers a grid that is renewable friendly.

[Johann]

1 ton = 12, 000 BTU of cooling= 1hp
These don't really make sense with today's efficiencies but they come from the early days of refrigeration when belt drive compressors were used.
A 1 HP motor was needed to spin a 12K btu compressor that was now replacing 1 ton of ice.

Where did you get to the conclusion that 1hp=12,000 btu=1ton ?

1hp =745.6 watts
1 watt = 3.41 btu

745.6 x 3.41 = 2542.49 btu

1hp = 2542.49 btu.....not 12,000 btu or 1 ton.