[tempestn]

I assume plug-in batteries are considerably more workable in the UK on 240V, since they could charge and deploy at double the rate of a plug-in system here. Of course 240V plugs exist in North America, but they're generally only installed for dryers, ranges, and EV chargers, so people don't tend to have one just free.

[NavinF]

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

[tempestn]

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.

[labcomputer]

> 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.

[Scoundreller]

What makes it easier on 240v systems is that your entire household is on the same “circuit”.

If you’re on a 120v system, there’s a ~50/50 chance that your load is on the wrong side (except for 240v loads where you’ll imbalance things a tad but it should average out).

Unless you’re in an apartment/conso and have 208v instead of 240v… dunno what happens then.

[bob1029]

Every US household has at least some big circuits across both lives. You could theoretically put the battery in the laundry room and use the 240v outlet. This is effectively what I did when my power was out during a hurricane. I backfed my entire house through my laundry room. Not to code but nothing was that week. The circuit wasn't rated for enough to handle the HVAC load so I eventually installed a separate 50A inlet on the side of the house.

[toast0]

> Every US household has at least some big circuits across both lives.

Not really. My parents have all natural gas for the furnance, oven, stove, clothes dryer, and water heater; no air conditioner. Everything else is lights and outlets. There are no 240v outlets and no 240v breakers other than the main breaker.

[Symbiote]

This is true for the British system, except for the largest houses (6+ bedrooms) where you'll have a three phase 415V supply.

Elsewhere in Europe it varies. Even small properties in Denmark and I think Germany have a three phase supply, my oven and stove use it directly.

[angry_octet]

There are multiple circuits on each phase, you would still need to limit current per outlet to 10A (8A sustained). If it's a dedicated circuit then 15A is fine, but usually that means a separate run, and in that case you can just have 20A or 32A.

When you have "three phase 415v", the 415v is the phase-to-phase voltage. Unlike the US 180 degree split phase 220v or 208v p2p, consumer equipment is not wired phase-to-phase unless it is 3-phase.

It's interesting that Europe has 3 phase cooktops, we usually see 32A single phase in Australia, homes rarely need more than 7kW per circuit. Aircons, pool heat pumps and EV chargers are the 3p loads.

Getting a 3 phase PV inverter is worthwhile if you have sun synchronous loads, like pool heater/chillers, across the phases. Then you will want a 3p battery inverter for the same reasons.

[angry_octet]

It would be very unlikely that your 240v system would all be on the same circuit, unless you have an antique UK ring main.