Tesla announces "Powerwall" batteries

[DanKegel]

it is 400 volt @ 25 AH.

That's your personal guess, right?

[bberry]

My point is that for solar they are not planning to do DC-AC-DC, as you alluded. They wouldn't have chosen 400v DC on the output side if that ruined efficiency when charging from solar.
The Model S, when on a supercharger, indicates only 400-405v charging voltage. Which is interesting. And perhaps relevant.

[Sunking]

I bet they are more clever than to only allow AC charging. Perhaps reconfiguring the pack in solar charge mode to halve the needed DC voltage.

225 volts? That makes no sense. Not what I think. I think Musk is smarter than that and will have a Propitiatory Solution (Expensive) from a Inverter manufacture he chooses as a partner. Wanna bet?

[Amy@altE]

From what I'm seeing from Fronius and SolarEdge is they are using one of the MPPT ports for solar, and one for battery.

[bberry]

Not gong to happen. Tesla battery uses standard 240 VAC @ 50 or 60 Hz to charge the battery. That does not come from solar panels directly. That comes from the utility or in a round about way a grid tied system for which you have no use for a battery. FWIW it takes a 450 volt source to charge a 400 volt battery.

I bet they are more clever than to only allow AC charging. Perhaps reconfiguring the pack in solar charge mode to halve the needed DC voltage.

[Sunking]

Thanks for the reply - and I completely understand the necessity of factoring in time of use. I just want to make sure my assumptions are correct - i.e. that amperage goes down as volts increase.

Also, that I would have to wire my solar array to output at least 350v to be able to charge a PowerWall if I chose to go that route.

Not gong to happen. Tesla battery uses standard 240 VAC @ 50 or 60 Hz to charge the battery. That does not come from solar panels directly. That comes from the utility or in a round about way a grid tied system for which you have no use for a battery. FWIW it takes a 450 volt source to charge a 400 volt battery.

[Amy@altE]

Just found this for the Euro version of the Fronius Symo Hybrid. http://www.fronius.com/cps/rde/xbcr/...1_snapshot.pdf

[Sunking]

http://www.teslamotors.com/powerwall just says "10 years". Since they haven't claimed DoD yet, people are making guesses (I've seen 70%, 80%, and "it's really a 12 kWh battery

Wrong it is 400 volt @ 25 AH.

If used off grid to be equal with a FLA you only discharge 33% per day vs 20% per day with FLA. Tesla claimed warranty is undefined. Its talk, no teeth, and absolutely no third party test data. Very few Lithium batteries have passed the IEC 61427 test protocol. Very few even dare to submit.

Find the manufactures who subscribe to 3rd party testing, use IEC 61427 like Trojan and a few others have. IEC 61427 is a brutal test protocol using real life parameters for Solar Deep Cycling., The test results strongly indicate the Trojan Industrial line are good for 15 years operating to 80% DOD daily cycling. Not many in that price range can touch those results. Even Trojans lower Premium Line test results indicate 8 to 9 year battery. Tesla would not dare dare to submit to the testing.

But if you really want to see who the Big Bad Boys are in battery long life look no further than Sandia National Lab Testing using IEC 61427. No Tesla to be found. On the Pb side you have East Penn Ultrabattery, Furukawa Ultrabattery pushing 15,000 cycles. On the Lithium side you have Altairnano Titinate at 40K, and International at 20K cycles.

Show me the test data and I will believe Tesla and that ain't going to happen. Until than forget it. Panasonic who makes Tesla batteries will not submit to the test. You can believe BS talk, not me it walks.

[Amy@altE]

They will probably call it StorFroun.

I wish! It's the Fronius Symo Hybrid. Doesn't quite roll off the tongue.

[Amy@altE]

Amy you need to read the latest from the shyster. You can buy the battery outright for $7000.

Right, my point, “For a 10 kilowatt-hour system, customers can prepay $5,000 for a nine-year lease, which includes installation, a maintenance agreement, the electrical inverter and control systems. Customers can also buy the same system outright for $7,140, Bass said.”

So $3500 for the battery + $2000 for the inverter = $5500, leaves $1640 for installation and maintenance agreement.

[Sunking]

The $7000 includes the inverter, obviously you'd need one regardless of which type of battery, and installation and maintenance. Figure at least $2k for the inverter, probably closer to $3k, and I can see where the $7k comes from. But I did the math, the price per watt for just the 7kWh battery is about the same as Aquion's stack, and 2X as much as the Trojan Industrial line and some AGM batteries.

Amy you need to read the latest from the shyster. You can buy the battery outright for $7000.

[RoadGlide]

The inverter manufacturers who are working with Tesla are making the inverter/charger one component. Currently, SolarEdge has you use their optimizers to input 350V from the array to the inverter. StorEdge (as it will be called) will treat the battery bank as an optimized PV string.

I'm not sure of the details of how Frounius will be handling it.

I understand that as well - however when I visited SolarEdge's website couldn't find any meaningful info. Perhaps it's still a bit early in the process as Tesla just announced the PowerWall.

I appreciate your help - thank you

[SunEagle]

The inverter manufacturers who are working with Tesla are making the inverter/charger one component. Currently, SolarEdge has you use their optimizers to input 350V from the array to the inverter. StorEdge (as it will be called) will treat the battery bank as an optimized PV string.

I'm not sure of the details of how Frounius will be handling it.

They will probably call it StorFroun.

[Amy@altE]

Thanks for the reply - and I completely understand the necessity of factoring in time of use. I just want to make sure my assumptions are correct - i.e. that amperage goes down as volts increase.

Also, that I would have to wire my solar array to output at least 350v to be able to charge a PowerWall if I chose to go that route.

Thanks again for the reply

The inverter manufacturers who are working with Tesla are making the inverter/charger one component. Currently, SolarEdge has you use their optimizers to input 350V from the array to the inverter. StorEdge (as it will be called) will treat the battery bank as an optimized PV string.

I'm not sure of the details of how Frounius will be handling it.

[RoadGlide]

You are making the common mistake of confusing watts and watt hours. So for your equations above, you need to add time into the math.

Thanks for the reply - and I completely understand the necessity of factoring in time of use. I just want to make sure my assumptions are correct - i.e. that amperage goes down as volts increase.

Also, that I would have to wire my solar array to output at least 350v to be able to charge a PowerWall if I chose to go that route.

Thanks again for the reply