Tesla unveils batteries to power homes

waynefromnscanada

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

Photowhit

I didn't watch and have to run to work but ponder whether they will try to have proprietary charge controller?

MarkC

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!!

JoshK

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.

inetdog

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.

Imurphy

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).