Tesla unveils batteries to power homes

The rechargeable lithium-ion battery unit would be built using the same batteries Tesla produces for its electric vehicles, analysts said.
The system is called Powerwall, and Tesla will sell the 7kWh unit for $3,000 (£1,954), while the 10kWh unit will retail for $3,500 (£2,275) to installers.
http://www.bbc.com/news/technology-32545081

Comments

  • PhotowhitPhotowhit Solar Expert Posts: 5,407 ✭✭✭✭✭
    I didn't watch and have to run to work but ponder whether they will try to have proprietary charge controller?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • MarkCMarkC Solar Expert Posts: 194 ✭✭✭
    Not too much info on the video, however;
    1. A matching charge controller would be a necessity if the battery pack voltages approach anywhere near the current EV designs - question if it is integrated at all with their EVs, or a totally separate Tesla initiative. For us Priups generator people, this is a big deal - can the batteries serve a dual purpose? Can it be designed safe enough for the casual user????
    2. The cost appears to be competitive with LiFePO4 technology - can anyone check this one?
    3. Wonder if it is actually Li-ion or one of the more stable Li technologies?
    4. If this is simply a "repackage" of available off-grid battery designs - with hype - so what!!
    3850 watts - 14 - 275SW SolarWorld Panels, 4000 TL-US SMA Sunny Boy Grid tied inverter.  2760 Watts - 8 - 345XL Solar World Panels, 3000 TL-US SMA Sunny Boy GT inverter.   3000 watts SMA/SPS power.  PV "switchable" to MidNite Classic 250ks based charging of Golf cart + spare battery array of 8 - 155 AH 12V Trojans with an  APC SMT3000 - 48 volt DC=>120 Volt AC inverter for emergency off-grid.   Also, "PriUPS" backup generator with APC SURT6000/SURT003  => 192 volt DC/240 volt split phase AC inverter.  
  • JoshKJoshK Solar Expert Posts: 232 ✭✭
    Photowhit wrote: »
    have proprietary charge controller?
    I understood it is built in. Good thing too, because Lithium battery SOC can not be determined with a voltage reading like the other types. I am sure that 10/20 year warranty doesn't apply if you hack your own charger on it.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    JoshK wrote: »
    I understood it is built in. Good thing too, because Lithium battery SOC can not be determined with a voltage reading like the other types. I am sure that 10/20 year warranty doesn't apply if you hack your own charger on it.

    Lithium chemistry does allow you to accurately determine SOC by voltage, is it just that the curve is non-linear and the slope of the central portion is very shallow.
    But outside the high SOC and low SOC knees of the curve you have a very good SOC indication.

    It is critical not to either fully charge (>80&SOC) or overdischarge your Li chemistry battery to get best calendar and cycle life. And with so many cells in series to get 300+ volts cell level battery management is critical unless you are able to guarantee that you stay in the central part of the SOC regime.
    Battery management involves both charging and load management.
    Boeing found out what happens when your BMS does not properly control the charging stage.
    SMA SB 3000, old BP panels.
  • ImurphyImurphy Registered Users Posts: 16 ✭✭
    It would be great to see a product like this make a move into every day applications. But I am not convinced. Its a great stepping stone but the cost is to grate for how little power you get. I would have to have 2 of these to replace the flooded cells in my motorhome, and 12 of them to take place of the plant in my home. They have a 10 year warranty because it will take at least that long being daily cycled to break even(7-12yr ROI, depending on your system).
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