Tesla Powerwall Follow-Up; New Details Cast Some Minor Doubt

dgstorm

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Here at HQ we are pretty excited about the new Powerwall from Tesla Energy that was just announced last week, but that doesn't mean there aren't some negatives to the new tech. Some new details have come to light suggesting the initial version will not be quite as disruptive as originally thought.

First, Tesla's solar energy company, Solar City isn't ready to endorse the Powerwall for use with their systems yet. Apparently, this first iteration wasn't designed to offer anything useful to Solar City customers because existing regulations allow users to sell unused energy back to the power companies. This means that the economics of the Powerwall simply do not yet make sense when used with the Solar City solar energy technology.

The second detail which throws a bit of shade on the Powerwall is that only the smaller 7kWh is designed for everyday use. According to reports, the 10kWh version isn't designed to go through more than about 50 charging cycles a year. The only advantage of this version of the Powerwall for folks with the Solar City tech would be as a battery backup device.

Of course, for the average homeowner who does not have a solar panel setup for their home, the 7kWr Powerwall is still an affordable way to lower energy costs, it's simply ironic that Elon Musk's own Solar City solar power tech company isn't ready to use the tech with their existing systems.

Source: Yahoo!
 

FoxKat

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Let's just clarify what a charging cycle is for the crowd. In the case of the 10kWh device that's completely charging to 100%, then using and charging a cumulative 100% of the capacity. For instance, say you have a grid power failure and while you're down you use 2kWh (2,000 Watts of power drawn for one full hour). Then when power resumes the device charges back to 100%. You have just used 1/5 (20%), of a full cycle. In that example this exact scenario would have to take place 5 times before you've used one full cycle of the 50 they claim it had. So in another example let's say you used 6kWh, then on the next power outage you use 4kWh. You would have also used a combined 10kWh and so that would constitute one full cycle of the 50 specified.

Second, rechargeable batteries are said to be end of life when they will only hold 80% of the specified capacity (or 8kWh in this case). Considering how infrequently most residential service suffers interruption even 10kWh and 50 cycles is likely to not be exceeded before the batteries reach end of life simply due to age (about 3 years).
 

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One more thing.
If you live in Ca. and have PG&E, this won't work to lower your bill because, we have tiered rates based on usage and not time of day.

To get a time of day plan you need an electric car. Now that I have an electric car, this would be great to reduce my energy costs even more.

Charge at night and use during the day.
 

PereDroid

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But you need to put Solar Panels on your house.... uh... ok... When I can afford a solar panel installation, I'll get excited about a battery to store that power...
 
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dgstorm

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No. You don't need solar panels to use the Powerwall. In fact, it was specifically designed for houses that don't have solar, and as I said in the article, it doesn't actually benefit most solar panel installations yet.
 

Remmy700P

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At its price point, it doesn't benefit ANY home. Run the math. The usable life of the battery pack is a fraction of the breakeven. It isn't even new "tech". It's simply a large, repackaged Li-Ion battery for gawd's sake.
 
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