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Is still hard for some of you to understand my calculations even if I made them reasonably easy. Battery cost per capacity as wk mentioned $200/kWh for a used battery has no meaning. Say that battery was good for only 10 cycles will you buy that ? The important aspect is cost for each kWh stored...

A more simple calculation related to the cost of energy storage using Tesla battery. Tesla S has a 200000km warranty on the 60kWh battery (I do not think there is any warranty to the capacity loss just battery defects) based on wikipedia page. Range seems to be around 350km so 200000km / 350km =...

I'm also quite curious to see what Tesla comes up with for home energy storage. I expect around 10 to 25kWh battery but I may be surprised. Using that as a hole house UPS makes sense if you have often outages for convenience. But it will never be able to recover the investment in any country...

I do repeat my position because is the right one base on the current evidence including that document. In that document there is a 3000 cycles test done at a very narrow DOD from 4.05V down to 3.6V and back up (that based on the okashira discharge curves will represent less than 30% DOD) I'm...

:) 2.5kWh storage is not useless to me. My house is more energy efficient than an average house by quite some margins about 10x was my target. My house is about 3x smaller than an average house and about 3x better thermally isolated so 3x3 close to 10x So my average 80kWh/month is also around...

Look wk's house size and power consumption is well above average so that is why that pack looks large. My 2.5kWh pack house size and power consumption is on the other end of extreme My battery pack is about the same size as the inverter and about the volume of a desktop computer. And I use...

I have good enough knowledge about Lithium batteries. For Laptops and EV normally you prefer energy density over cycle life. Do you find about 300000km insufficient for a car? Currently in average cars are driven around 25000km/year that is about 12 year for that battery to get to 80% and seems...

Do you have any spec for the NCA. I doubt is any better than NCR in therms or cycle life. They are mostly interested in energy density for cars and it makes sense.

Do you have any proof the cells use different chemistry and if so what is the chemistry? As I mentioned in earlier comments that 300 cycles done by Panasonic are 100% DOD If you charge the cells mostly to 80% SOC and then discharge them to 10 or 20% SOC even better most of the time then life...

I see about 7% or 8% here from 3.2V to 2.5V at C/3 is not worthed to go below 3.2V

For long battery life in stationary storage applications it makes no sense to go below 3.2 or 3.3V. If you look at a discharge curve for this type of batteries you will see that is less than 5% capacity left at 0.25C, the additional stress on battery is not worthed for this 5% or less.

I possible that utilities will not always pay the same for what you sell but even at 30% is good and you will still recover the investment. The PV panels last easy 25 years and if you use that as amortization period the cost will be 3 cent/kWh considering you paid 1$/Wh for them. But most of...

I'm sure your power consumption is well above an average house in US. This is less important since you can use as much as you want and you just need to pay for that. I do not understand why will you want to go offgrid ? What is the benefit ? It's probably much more expensive than grid power at...

I see some large amount of electricity used. If most of that is used inside the house than all of that will convert to heat and then AC will be needed to extract that heat. (But maybe most of that energy is already because of the AC). I men tined before that my house is extremely small 65sqm...

I made a longer comment but not sure if that will be approved. Dose someone have a link to Tesla cell spec? since some of you mentioned that the Panasonic NCR cells are not as good. For EV it was a good decision to use those batteries with 2x the energy density of LiFePO4 but since as I...

I seen quite a few replays to my comment about the NCR battery life. Some of you mentioned that they use a different battery or improved battery. Do you have any spec for the particular one Tesla is using? I'm not saying that Tesla chose a bad battery because they did not for an EV car. I'm just...

I looked for the spec on NCR18650A and it dose not look great for energy storage. It seems that after 300 cycles it only has 80% of original capacity. Compared to a typical LiFePO4 3000 cycles before it gets to 80% of original. Not sure how much will that improve if cell is not cycled that deep...

I seen this on Blomberg first. I was reading trough the posts and this is a monster off-grid installation :). It seems you even purchased more battery modules than the initial pack. I live OffGrid for not that long I will have two years this spring. I use LiFePO4 for a few reasons (excellent...