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Tesla Energy

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Re: Tesla Energy

#442

Earlier quoted context omitted.

You ever try to put out a gasoline fire with a garden hose?

While you are correct, you can at least snuff out a gasoline fire. Lithium fires do not require oxygen, so your typical Class ABC fire extinguishers won't actually work on it. You need a class D (dry powder) extinguisher, which is very rare and expensive.

> Lithium fires do not require oxygen

I thought fire is by definition a combustion reaction, meaning some kind of material reacting with oxygen. What's fire, then? (I feel like a little kid, having to ask that...)

Re: Tesla Energy

#443
post #386

Earlier quoted context omitted.

Does your insurance company allow you to keep one liter of gasoline in your garage? It has the same energy content as the Powerwall, is insanely flammable, is frequently implicated is home fires, and regularly causes human deaths. (Ok, a burning lithium battery will release more energy than its storage capacity, but I'm not finding a nice reference, Tesla knows all about containing cells to prevent chain reactions, a…

Gas fumes are very flammable, but the gasoline itself will flow down and out of my garage, and the fire would be very easy to contain with a simple garden hose. A gas can also will not light on fire just because it gets hit with a car. It would take malicious use of a gas can -- splashing it on a wall and then lighting it on fire -- to match the default configuration of a Powerwall.

It's common advice not to leave rags that have gasoline on them sitting in your garage because in enough heat the fumes from the evaporating gasoline will combust. Gasoline is very volatile, we've just gotten fairly good at managing it.

Re: Tesla Energy

#444
I know they pitched this for solar, but I bet that won't be the most common use, at least initially.

My power company (XCel, if it matters) keeps trying to install a "Saver Switch" in everyone's house to shut down their A/C when demand is high. Basically they want to load shed your air conditioner, and they're willing to pay you for the privilege.

This is a lot more expensive, but it's also a hell of a lot more versatile. How much would it be worth for them to subsidize installing these with a switch that would let the utility remotely toggle you off the grid at their discretion? Plus it would actually save consumers money in any market with tiered electric rates. Plus it would help them deal with the intermittency of solar power.

Re: Tesla Energy

#445

For those interested in investing and finance, I have a question. Why would this news not cause Tesla's share price to go up? It seems generally well-received (well, as much of an indicator as 812 points on HN is). Surely that's a good sign? Or did the announcement not live up to the hype, causing people to dump stock?

Tesla stock price has been gradually increasing the last week or so in anticipation of the event, so the event has already been "priced in." Further, the FOMC (fed) recently scared the market, because interest rates may be rising some time in the future (September? December? who knows), causing people to switch from investing in equities (stocks) into treasury bills. In short, this information was already anticipated but it also had to fight the FOMC announcement.

Re: Tesla Energy

#446

Earlier quoted context omitted.

You ever try to put out a gasoline fire with a garden hose?

While you are correct, you can at least snuff out a gasoline fire. Lithium fires do not require oxygen, so your typical Class ABC fire extinguishers won't actually work on it. You need a class D (dry powder) extinguisher, which is very rare and expensive.

While true for lithium fires, a venting lithium-ion battery is not a typical lithium fire.

According to the MSDS for lithium ion batteries, fires involving them can be extinguished with a typical ABC fire extinguisher.

Lithium batteries (not the rechargeable kind) are the ones that need a class D extinguisher.

Edit:

> CO extinguishers, halon or copious quantities of water or water-based foam can be used to cool down burning Li- ion cells and batteries. Do not use for this purpose sand, dry powder or soda ash, graphite powder or fire blankets.

> Extinguishing media Use water or CO2 on burning Li-ion cells or batteries

http://www.uscg.mil/hq/cg4/cg432/docs/msds/MSDS_LiIon.pdf

Re: Tesla Energy

#447

For those interested in investing and finance, I have a question. Why would this news not cause Tesla's share price to go up? It seems generally well-received (well, as much of an indicator as 812 points on HN is). Surely that's a good sign? Or did the announcement not live up to the hype, causing people to dump stock?

Tesla stock price has been gradually increasing the last week or so in anticipation of the event, so the event has already been "priced in." Further, the FOMC (fed) recently scared the market, because interest rates may be rising some time in the future (September? December? who knows), causing people to switch from investing in equities (stocks) into treasury bills. In short, this information was already anticipated…

Thanks. Makes sense.

Re: Tesla Energy

#448
post #379

Earlier quoted context omitted.

Lithium mining has relatively little environmental impact: it's mostly evaporation of lithium-rich brines. But lithium is still not cheap. I suppose that a different battery technology, with lower energy density per unit of weight, could be much cheaper with comparable efficiency. But Tesla only has expertise in lithium batteries, so some other manufacturer could use the momentum with a lower-cost offer.

> But lithium is still not cheap. Lithium is extremely cheap. The cost of the Lithium has practically no impact on the cost of the batteries. Most of the cost of batteries is work. This venture makes sense because as lithium batteries are used, they lose capacity, and thus their specific energy gets worse. At this point, they are no longer very useful for cars, yet still can be used for other things. As Tesla recover…

do you have a cost breakdown for a Li ion battery?

Re: Tesla Energy

#449
post #346

Earlier quoted context omitted.

Would you not install the battery in a heated place in your house (garage, basement, furnace room)?

I have the opposite problem: Living in Texas, my garage easily gets above 110F many days during the summer (it would be crazy to pay for A/C in it). But, I'm also not going to put the battery pack(s) "inside" my house (e.g. utility/laundry room).

But, I'm also not going to put the battery pack(s) "inside" my house (e.g. utility/laundry room).

Why not? The whole point to making it wall-mounted is that it won't take up any substantial amount of space. A utility/laundry room seems like exactly the logical place that you would want to put it.

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