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Comment by toomuchtodo | Hacker News Reader

I would suggest 200A service as a bare minimum, with 400A being ideal (this will be heavily dependent on your electric utility service entrance). Consider two EVs, HVAC loads, and possibly electric water heaters, clothes dryers, and a stove. Also, NEC 80% derating (100A circuit required for an 80A 100% duty cycle load).

The electrician's time is the most expensive part; oversize for decisions such as these (load center, EV run to outlet, subpanels, etc).

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After putting up panels at my relatively modest house, I’m honestly surprised at the kind of juice I can produce. I’m ready to convert everything I have to electricity

If you didn't put a battery in at install time, there's a recent IRS determination suggesting [1] you can still receive the 30% tax credit if the battery is installed at a later date. I would highly recommend pulling the trigger right before the tax credit begins its phase out at the end of 2019, assuming costs come down further between now and then.

The caveat is that your system must charge the battery from your panels, and cannot charge from the utility (trivial inverter setting). With that said, based on net metering laws in most locales, it behooves you to consume as much of your own production as possible. Exceptions abound.

https://www.reddit.com/r/energy/comments/82fchy/irs_letter_o...

We have net metering here, so the grid is basically my battery. It would be more worthwhile if I could charge from the grid but I’m way overproducing as is.

200+ A circuits in a residential home really makes a point for 400 V three phase (where the same load would be ok with a standard 63 A circuit, which is still a lot). [1]

However, when more and more people try to have fast chargers in their homes for EVs, then not only the residential installation poses a problem, but utilities would need to rebuild ~two layers of distribution to accomodate for a 100-200 % increase in residential power consumption.

[1] Not just because high currents are more difficult to handle properly, but also because you need a lot less copper.

If you live in a subdivision built within the past couple decades, your electric runs underground, making it quite expensive to run a second or third primary phase. You also then need a three-phase transformer, which is considerably larger than a typical one-phase. Oh, and your service will be commercial/industrial, which typically comes with demand and energy charges that can be quite steep: https://www.northwesternenergy.com/docs/default-source/docum...

That's true, for North America, but entirely misses the point I made (i.e. when you try to push dozens of kW into a house, single phase becomes worse than a below-average idea).

Which is one of the logical conclusions of products like the PowerWall. I think the current model can only run like 25 amps but an in house fast charger that can pull 10 or 20 amps during off peak hours and dump 60 amps when charging the car could be a cheaper installation.

Hell if the PowerWall 3 could dump 40 amps you could pull 20 from the wall at the same time and hit your 60 amp total.

If your utility lets you do this... in many areas, increasing your service amperage is expensive if you don't use a majority of that additional capacity.

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