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Comment by disentanglement | Hacker News Reader

A 1 MWh battery isn't actually that big. There's electric trucks on the market right now with 600 kWh batteries sitting on the frame between the front and rear axle. That would easily fit into a basement room.

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I wouldn't want a battery in my basement. if there is a fire in the battery your house will turn into a smoking hole, in the literal sense. Maybe if it was an iron-air battery or something safe, but not the current generation chemistry batteries.

" but not the current generation chemistry batteries."

Check for "Saltwaterbatteries", they are starting to reach consumer markets and literally cannot burn as the energy is stored as ... salt water.

Seems like the peak was around 2017 but they never performed particularly well?[1]

The problem is if the promise from the name was true, they'd be everywhere - they're not, so invariably much like vanadiun-redox or iron-flow batteries it turns out all the other details make them more expensive and less performant.

[1] https://en.m.wikipedia.org/wiki/Aquion_Energy

" if the promise from the name was true, they'd be everywhere"

Not necessarily. Lithium is still quite cheap, safety is not the number one demand - and it is mainly about optimizing production to achieve competive pricing.

So yes, mabye there are some blocking details I am not aware of, but otherwise I expect their time will come.

Yeah, I'm not saying it's a good idea. But you could do it if you wanted to.

A sand battery would work[0] if you have the space ;)

https://polarnightenergy.com/news/worlds-largest-sand-batter...

LFP should be about as safe as other stuff people tend to store in their basements.

LFP's biggest issue is people aren't used to "Phenomenal Cosmic kW/h... itty bitty living space!" Yet.

Even if it was a safer chemistry, I would still put it outside of my house, likely in a dedicated structure. Its a shit ton of energy potential regardless, and it can make maintenance and modification down the line way easier.

A good size comparison might by approximately the size of a stand up freezer, a common basement sight.

That small? I was imagining burying a shipping container under the driveway/front yard or something.

Most grid-scale batteries that large will have bigger inverters (usually it'll be inverters that can dump that energy in 2-6 hours so 500-150 KW for 1 MWh of battery) and require cooling systems and such, but if you're putting that in your home then cooling will be negligible and the inverter will remain small. The batteries themselves are fairly compact, it's the support systems that get large.

Shipping containers should never be buried. They are not designed to tolerate forces pushing in on the sides and can collapse.

What's the degradation cycle on batteries that size?

If you're using daily, do you get... three? five years?

Looks like - https://cartroubleshooters.com/how-long-does-a-tesla-home-ba... - ten to fifteen years with a guarantee of 10 years at 70% from Tesla

We're to the point calendar aging instead of cycles is the existential threat.

We can roughly estimate lithium ion batteries as 500 watt-hours per liter. Which makes a million watt-hours 2000 liters, which is two cubic meters. Add in extra overhead and it's still not all that much.

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