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Comment by NavinF | Hacker News Reader

What percentage of buyers do you imagine are gonna buy a battery big enough to saturate 15A*120V=1800W for long? The average home uses 30 kWh per day = 1250W. Batteries don't need to handle peak load. Approximately nobody has a whole home UPS.

Also 240V power strips are fairly common in my circles because GPU server PSUs tend to be more efficient at 240V. They're marketed as PDUs, not strips. You're not gonna install a new outlet for every server. One dryer outlet in the garage is enough for most people

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I'm not clear what point you're making about PDUs.

Re 120V outlets, while batteries don't need to supply the full peak load, they are more effective the more of it they can supply. And a home with a heat pump or baseboard heaters, electric range, EV charger, or dryer for example is going to at times significantly exceed the capacity of the 120/15 outlet. Doesn't mean the battery would be useless, just that it wouldn't be as effective at its primary purpose of load shifting as a 240V system, and therefore less economical.

My point about PDUs is that "people don't tend to have one just free" is irrelevant. It's easy to split a 240V outlet into multiple outlets. One of them can be used to inject power. The copper doesn't care which way the electrons go.

Heat pumps and baseboard heaters are pretty uncommon in the US. Natgas furnaces are nearly 100% efficient so I don't expect that to change any time soon

Oh, I see. Yeah, good point about splitting a 240V outlet. Not as convenient as having them everywhere, but it'd certainly be possible.

NG may be 100% efficient, but heat pumps are like 300%+ in terms of electricity to indoor heat. And you get air conditioning.

> What percentage of buyers do you imagine are gonna buy a battery big enough to saturate 15A*120V=1800W for long?

You can get 10kWh of batteries and a 5kW MPPT chargeverter for a little over $2k these days (UL certified). A 30 kWh system with inverter can be had for around $4k. That’s well within the reach of most households.

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