The answer is mostly that the powerwall is an incredibly overpriced home battery.

They want ~9k for a freaking 13.5kwh pack.

I can buy a UL certified, 16kwh, outdoor rated pack for 3.5k (ex - EG4 allweather)

I can buy just the LFP batteries themselves for the new powerwall 3 LFP version (no BMS, no shell, no certification) for $1116... https://18650battery.com/products/byd-302ah-3-2v-lifepo4-pri...

Powerwall is a scammy product. WAY too expensive for the storage it provides.

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So the summary is: Cybertruck is using a different battery chemistry, Powerwall is a scam.

(I mean - to be clear, the Cybertruck is also a scam, but it's a different kind of scam not directly related to the battery capacity, since it's hauling around a 123kWh NCMA battery pack)