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jonhohle • today at 4:12 PM • 5 replies • view on HN

Many EVs can do the same thing.

It’s unclear to me how a vehicle battery can be 9-10x the size of a house battery, be used as a house battery, include an highway safe cabin, motors and wheels and only cost 4x what a single home battery costs. Oh, and at least Kia rates their battery warranty based on miles driven, so using it as a home battery does not impact any 10-year capacity guarantees.

AI tells me they are completely different though, so I must be missing something.


Replies

cogman10 • today at 5:09 PM

What you are missing is home batteries have INSANE markups.

5kWh of battery cells at the moment run around $500. The rest of the cost of production is in the power electronics (probably around another $500).

It's why you can buy 4kwh worth of battery backups from Amazon for about $2k right now. Yet the same thing sold as a home battery backup costs $5k.

Lack of competition and likely low amount of sells is what's causing the margins to be so high.

hedora • today at 5:02 PM

Permitting in California more than doubles the installation cost of home batteries + PG&E gets to screw with you if you buy one.

Propane generators here have the same problem.

That still doesn't explain the price gap. You can literally just get a V2H EV and use it instead of a home battery (or, you could if the ecosystem was more mature).

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twoWhlsGud • today at 4:35 PM

Good question - different markets with different margins and supply chains?

horsawlarway • today at 4:38 PM

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)

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