Tesla powerwall

Now we know what Tesla's going to do with all the old reduced capacity battery packs they remove from their vehicles.
 
Only 5.8 amps nominal. I'd rather have the tiny 50cc Honda generator that does 7.5.
 
From what I'm reading its purpose is as a power sink for areas where day and night rates differ and/or where you get different rates on power you produce vs. consume (for a variety of reasons). You buffer power from the cheaper hours and use it in the more expensive. I don't really see a big upside there in most places and this is probably more a "see, we can do it" stunt. The price is cheap for that kind of battery, and that is a good indicator it is really some kind of test flight.

$250/KWh is a good price on deep discharge AGM lead-acid cells... and you can't fully discharge them without impacting their service life. This is $3500 for 10KWh ($350/KWh) you can discharge all the way down and it's all packed and wired (you can probably guess what the cabling on a bank 10KWh of AGM cells runs). I don't see the inverter included so I don't know where they come up with the 92% efficiency. Nor do I see the charge controller. So I'm taking this as a decent, below market price on a brick of high-end batteries. No more. It's a neat idea and I am guessing Tesla isn't making any near-term money on this. If it happened that I needed a big pile of batteries for some kind of home power system, I'd be looking at these. By comparison, long-life NiFe batteries run about $800/KWh (and more).
 
jasons said:
Only 5.8 amps nominal. I'd rather have the tiny 50cc Honda generator that does 7.5.
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It looks like that current at the 350-450v rating. They claim a 2kW continuous, 3.3kW peak output. That's pretty good for a backup I'd say.

For a battery that's only 7" thick, albeit wide and tall, those are some decent numbers. I think we're going to be seeing some real gains in battery capabilities in the next few years that make running your home off solar 24/7 a reality.
 
strangenh said:
From what I'm reading its purpose is as a power sink for areas where day and night rates differ and/or where you get different rates on power you produce vs. consume (for a variety of reasons). You buffer power from the cheaper hours and use it in the more expensive. I don't really see a big upside there in most places and this is probably more a "see, we can do it" stunt. The price is cheap for that kind of battery, and that is a good indicator it is really some kind of test flight.

$250/KWh is a good price on deep discharge AGM lead-acid cells... and you can't fully discharge them without impacting their service life. This is $3500 for 10KWh ($350/KWh) you can discharge all the way down and it's all packed and wired (you can probably guess what the cabling on a bank 10KWh of AGM cells runs). I don't see the inverter included so I don't know where they come up with the 92% efficiency. Nor do I see the charge controller. So I'm taking this as a decent, below market price on a brick of high-end batteries. No more. It's a neat idea and I am guessing Tesla isn't making any near-term money on this. If it happened that I needed a big pile of batteries for some kind of home power system, I'd be looking at these. By comparison, long-life NiFe batteries run about $800/KWh (and more).
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Useful as solar storage for a bugout spot?
 
strangenh said:
From what I'm reading its purpose is as a power sink for areas where day and night rates differ and/or where you get different rates on power you produce vs. consume (for a variety of reasons). You buffer power from the cheaper hours and use it in the more expensive. I don't really see a big upside there in most places and this is probably more a "see, we can do it" stunt. The price is cheap for that kind of battery, and that is a good indicator it is really some kind of test flight.
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Good point, I missed this. I guess it's not valuable to me, then.
 
Ah, looking at the spec sheet, I see now. These are meant to be in effect inline with the solar panel DC line, supplying continuous DC to the solar DC/AC inverter. They must have their own charge controller. So if you want this for off-grid, you need an off-grid solar inverter (i.e., one that will keep providing power with no external 60Hz source). Interesting concept but if you have an on-grid inverter, these won't be providing you power in an outage without some kind of smart grid controller (like a Sunny Boy/Island setup).

Still a very good price on the batteries, which is of course their incentive to get market adoption.
 
Yes, if you have an off-grid capable solar inverter, I think that would work. I think they are a little expensive compared to regular lead-acid, but about on par with low maintenance deep discharge AGM lead-acids once you factor the additional wiring and enclosure (and charge controller / battery inverter). I suppose for a bug-out cabin, you'd want low maintenance so take AGMs as your pricepoint.
Squire said:
Useful as solar storage for a bugout spot?
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ToddDubya said:
It looks like that current at the 350-450v rating. They claim a 2kW continuous, 3.3kW peak output. That's pretty good for a backup I'd say.

For a battery that's only 7" thick, albeit wide and tall, those are some decent numbers. I think we're going to be seeing some real gains in battery capabilities in the next few years that make running your home off solar 24/7 a reality.
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Yeah I think you're right. Looks like it outputs 350-450 volts DC and you have to supply your own inverter to make it into usable power. (And a transfer switch.) I guess if you wanted to cache cheap power or keep the fridge and lights on during a short power outage it could work. Still seems a bit expensive though.
 
If that lithium ion battery bank fails, even if you're there your house is still burning to the ground.
 
Hopefully this will lower the price of batteries and someone will make a more practical bank for small scale applications. A 500v battery is not easy to charge or consume with low cost inverters or charge controllers.
 
Fits in well with his current solar power scheme, im guessing there will be tax benefits in this for him as well.
 
richc said:
As a few Tesla automobiles have done after sustaining some damage. That's a real concern.
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Indeed. With AGMs, failure means venting hydrogen, but indoors one generally installs banks of them with a passive vent.

Fire from system failure is probably a risk with any high-density, high-efficiency electrical power storage, and those LIon batteries are a good 1/3 the size of similar power in lead-acid format.

The actual failure rate to fire and the conditions for that failure would be good to know. Probably too few large LIon systems out there to have good stats yet. If they only experience catastrophic failure on taking serious physical damage, it is a different story from "*** could happen, sorry."
 
derek said:
If that lithium ion battery bank fails, even if you're there your house is still burning to the ground.
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I wander what insurance companies will think of that? Probably will want to jack up rate ... but then it's "solar, discrimination ... ZOMG!" and the rest of consumers have to pay for this bullshit.

The real kicker would be that DC-AC battle between Edison and Tesla may end up being won by Edison after all. I can see more appliances may use DC as an option if DC storage becomes more widespread.

Of course like with anything Tesla, you get a bit of new tech, add a whole shitload of old tech and sell it like some ****ing revolutionary invention ... like segway or something.
 
FreeWillie said:
Nothing says you *must* store the batteries in your home. An out building would work very well.

sent from the depths of HELL using TapaTalk.
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but they are marketed as a "garage wall hanger" ... which will be the way most idiots who had never seen a Li+ battery on fire will. Again, this will jack up insurance rates for everyone, solar or not.
 
Do the math, only 6x more expensive than a generator.

Betcha mr musk is bummed he doesn't get any govt kickbacks from this scheme like all his others.
 
There are similar solutions available that are much cheaper. They have solar grid tie inverters that you can plug into an outlet to back feed the system. Most of the solar solutions do not work when the power is out. If they did you would be trying to power the whole neighborhood and it would also be dangerous for line crews
 
Boris said:
The real kicker would be that DC-AC battle between Edison and Tesla may end up being won by Edison after all. I can see more appliances may use DC as an option if DC storage becomes more widespread.
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I was just thinking the same thing. AC ended up winning out because it could be transmitted over long distances in relatively thin wires with very little loss. Most appliances already use DC electricity by converting the wall AC to DC, usually with significant loss and waste via "phantom loads" (the electricity that the AC->DC transformer in many household electronic devices uses constantly, even when the device is turned off). Depending on whose statistics you use, phantom loads make up between 10% and 25% of the electricity used in America. If this battery bank is as efficient as they claim, and can be proven to be safe, it would create huge incentives for many houses to go off grid, or have the grid as their backup system. If there electricity isn't being transmitted over long distances, there's far less need to generate AC power, making DC more attractive. If the electricity in the homes is now DC, there is no more need for the transformer in individual devices leading to significantly reduced phantom loads. It also reduces the need to have an inverter which also has it's own inefficiencies.

Funny that in the end it may be a company called Tesla that is the reason that Nicola Tesla ultimately lost the current war.
 

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