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Comment by cagenut | Hacker News Reader

The details are up on the site: http://www.teslamotors.com/presskit/teslaenergy

   The Powerwall is available in 10kWh, optimized for backup
 applications or 7kWh optimized for daily use applications. 
  Both can be connected with solar or grid and both can provide 
  backup power. The 10kWh Powerwall is optimized to provide 
  backup when the grid goes down, providing power for your home 
  when you need it most. When paired with solar power, the 7kWh 
  Powerwall can be used in daily cycling to extend the 
  environmental and cost benefits of solar into the night when 
  sunlight is unavailable.

  Tesla’s selling price to installers is $3500 for 10kWh and 
  $3000 for 7kWh. (Price excludes inverter and installation.)

Deliveries begin in late Summer.

View on HN

Meanwhile, in lead acid battery land, a Trojan T-105 is ~$150 for a 6 volt, 225 amp hour battery, which you might comfortably cycle 0.9kWh each day for 5+ years. Use 12 of them to match the 10kWh Powerwall and it only costs $1800, replace them at the end of 5 years and you have about the same cost as the 10 year Powerwall. Powerwall is several times smaller and lighter and presumably doesn't give off hydrogen gas when you charge it or burst and flood your room with sulphuric acid if you get to freezing temperatures with a discharged battery bank (done that), so there are certainly plusses.

It just isn't the silver bullet I was hoping for. I've been putting off replacing my batteries in a cabin while I wait for this, I suppose I'll nurse them through the Summer and make a decision in the Fall.

You need 20, not 12, don't you? 6V*20 = 120V

edit: the Powerwall runs at 350-450V, 5 amps nominal. Guess it depends on the inverter you use.

The voltage is irrelevant. You can run an inverting 120VAC power supply from one battery, or a hundred, as long as it supports the right voltage range. Yes, putting 20 6V batteries in series would give you 120VDC, but that's not particularly useful.

What matters is the energy capacity, which is measured in kWh.

The 12 number comes from energy storage capacity. Voltage conversion and DC to AC is handled by your inverter/charger which is a separate item.

I guess the question is how long the powerwall is expected to last, and how novel the linking of them is (I have no idea). Additionally, we can hope that once the gigafactory is up and running, or version 2 of it is, that prices drop.

Really, I think the big advancement here is attractive packaging of the product and experience, a la Apple.

I assume the Powerwall includes an inverter, what do they run?

At $150 a battery its a pretty good deal. There is a guy here in Ontario Canada that sells them for that price as well. His site is http://cartguy.ca/ ( E-mail: sales@cartguy.ca

Toll free: 1-888-905-2278

Our Location: 2933 Hwy 35 S, Lindsay, On K9V 4R4

Our Mailing address: 2 Peel St, Lindsay, On K9V 3L7)

He also has the Trojan T-105RE for $199 a piece.

Not sure if the advantage of the T-105RE is worth it.

Does anyone have any experience with the pricing here and could elaborate a bit wether or not this is a good deal? This does seem enticing at first glance, but I am unfamiliar with any hidden costs there might be in going with a solar + backup system such as this.

$3,000 for 7kwh and $3,500 for 10, both sound unbelievable to me. My first thought is there's a missing zero on the end.

Recently had a quote in Australia for >$AUD12,000 for a 5kwh battery set.

This is going to change everything to do with solar installations I think. Currently battery packs are a rarely taken up optional component.

Somebody just stated that technically this would feed the average home consumption of energy for about 8 hours. Why is this a good deal, even if it were 24 hours?

Would the benefits of solar power being extended into the evening be worth it? Back of the envelope calculations:

If you can run on solar all night there's potential savings. Assume 10kWh costs $1. If you have a surplus of solar during the day and you fully deplete at night, you theoretically save $365/year. Break even is at 10 years, which coincides with the warranty.

Well for me, I'm paying just over 22c/kwh, last period we used 808kwh over 80 days, so almost bang on 10 per day.

So with a solar setup that could charge a 10kw pack each day I could almost go off grid. That would save me nearly $1000/year once you take into account daily connection charges.

So the batteries would be paid off in 3-4 years, add a few years for however many panels I need and that's a pretty decent saving for no more power bills.

Of course it depends how long they are likely to last after that 10 year warranty period - no point swapping utility bills for tesla bills for replacements every 10 years.

> no point swapping utility bills for tesla bills for replacements every 10 years

Well, there could be additional benefits, such as not being linked to the grid and it's occasional problems (not to mention you aren't drawing power provided in part by coal). Then again, an extended period of low solar energy could have it's own problems.

I don't know about your consumption but ours is definitely 'bursty'. If we could have a battery with some surplus to offset some of our breakfast/lunch/dinner + laundry routine it would pretty much eliminate most of our energy bill.

However, I might be completely wrong about how this works.

> The details are up on the site: http://www.teslamotors.com/presskit/teslaenergy

I'm just seeing the normal Tesla homepage. Did they take it down to avoid stealing the thunder from the livestream?

EDIT: Back up now

http://www.teslamotors.com/powerwall

http://www.teslaenergy.com/

For context, how much does a typical household use? Assume a central A/C, 4 tv's, fridge, washing machine, etc.

According to the EPA [1], an average home consumed 12,069kWh in 2012. So assuming a constant load, a 10kWh battery would power about 7.5 hours of usage.

[1]: http://www.epa.gov/greenpower/pubs/calcmeth.htm

So if I'm reading this right - if I bought a Powerwall from Tesla and hooked it up to some solar panels, my power bill would DRASTICALLY decrease?

Your utility company is going to want to charge you a fee (or take a cut of what you sell to the grid) for not buying any electricity from them, so that they can maintain the power lines and substations to your home.

A solar array would expedite charging, but I believe they intend to monitor energy supply rates and charge based off that as well. eg. When rates dip, it charges at a higher rate.

Sure, but the same would be true if you bought solar panels and lead-acid batteries, which are cheaper (but less compact). Or if you bought just the solar panels, and sold the excess power back to the grid (assuming your utility provider allows that).

If you buy enough solar panels and one of these, you can remove yourself from the power grid and pay 0 with conservative nighttime usage (for an American home) buy two and you don't need to be so conservative.

"enough solar panels" isn't exactly cheap though.

> 4 tv's

Some funny definition of "typical household". The maximum I've seen in recent years is one TV per household, and the average way beneath that.

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