We generally provide a 10-year “no defect” and “energy retention” warranty with every current Powerwall and a 15-year “no defect” and “energy retention” warranty with every current Powerpack or Megapack system. Pursuant to these energy retention warranties, we guarantee that the energy capacity of the applicable product will be at least a specified percentage (within a range up to 80%) of its nameplate capacity during specified time periods, depending on the product, battery pack size and/or region of installation, and subject to specified use restrictions or kWh throughputs caps.
Assuming a daily megapack cycle, that’s 5475 cycles over the 15 year warranty period. This would line up well with the cited “6000 cycles” for some LFP cells used for solar energy storage. It also means a price per kWh of 265⁄5475 = 4.8 cents per kWh, not 27 cents.
In addition, the true expected degradation, assuming competent engineers at Tesla, is likely less than that, with real expected lifespans probably around 20 years in order for a 15 year warranty to be financially viable.
Do you have any data or cites that disprove this, and are they more credible than this source?
The Powerwalls are over-provisioned, which is part of why they cost $600+/kWh.
They don’t expect full daily charge-discharge cycles, and were willing to eat the cost of replacements for the fraction of people who did that, hoping for lower battery costs by that point.
The Powerwall 2 warranty is, if charging off anything except exclusively solar, limited to 37800 kWh on a 13.5 kWh battery that’s somewhat overprovisioned. Which is...about 2000 cycles. The warranty promises 70% of nominal capacity by that point. (By that point, resistance would also be quite a bit higher.) Even with those limits, I expect a decent number of replacements under that warranty.
I have found strong evidence falsifying your theory.
From Tesla’s 10-k filing : https://web.archive.org/web/20210117144859/https://ir.tesla.com/node/20456/html , which has criminal liability if it contains false information.
Energy Storage Systems
We generally provide a 10-year “no defect” and “energy retention” warranty with every current Powerwall and a 15-year “no defect” and “energy retention” warranty with every current Powerpack or Megapack system. Pursuant to these energy retention warranties, we guarantee that the energy capacity of the applicable product will be at least a specified percentage (within a range up to 80%) of its nameplate capacity during specified time periods, depending on the product, battery pack size and/or region of installation, and subject to specified use restrictions or kWh throughputs caps.
Assuming a daily megapack cycle, that’s 5475 cycles over the 15 year warranty period. This would line up well with the cited “6000 cycles” for some LFP cells used for solar energy storage. It also means a price per kWh of 265⁄5475 = 4.8 cents per kWh, not 27 cents.
In addition, the true expected degradation, assuming competent engineers at Tesla, is likely less than that, with real expected lifespans probably around 20 years in order for a 15 year warranty to be financially viable.
Do you have any data or cites that disprove this, and are they more credible than this source?
The Powerwalls are over-provisioned, which is part of why they cost $600+/kWh.
They don’t expect full daily charge-discharge cycles, and were willing to eat the cost of replacements for the fraction of people who did that, hoping for lower battery costs by that point.
The Powerwall 2 warranty is, if charging off anything except exclusively solar, limited to 37800 kWh on a 13.5 kWh battery that’s somewhat overprovisioned. Which is...about 2000 cycles. The warranty promises 70% of nominal capacity by that point. (By that point, resistance would also be quite a bit higher.) Even with those limits, I expect a decent number of replacements under that warranty.
The megapack is not a Powerwall. Powerwall uses nca cells. Megapack uses LFP. The cycles you calculated are correct for good nca cells.