Hello from England and a comment on max charging rate

I'm charging at home right now. Here are the stats:

14.7 amps

243 volts

3.57 kW

 

An interesting test would be to borrow a UK Volt 'granny charger' and see if it is adjusting the charging current between '6 and 10 amp' with the Prime set to MAX.

I'm thinking this may be a case of dealing with different grid systems:

• 230V, single phase, 13A - UK
• 120V, split phase, 15A - USA
• 210V, two of three phases, 30-50A - USA commercial
• 240V, both phases, 30-50A - USA

The portable charger in the USA is rated at 120V so it is easy to limit the charging current to 12A, the 80% of 15A. Plug into a 210-240V, the maximum 16A could be drawn if the portable didn't blow a fuse.

We are seeing multi-voltage, multi-current EVSEs in the USA market. Still expensive, they are small enough to replace the portable EVSE yet flexible enough to handle up to 20-22A from 120, 210, or 240V outlets (they can come with adapters.) But owning two plug-in hybrids, I am skeptical about using L2 chargers for significant range extension:

• ~3.3 kW ~= 9 miles in an hour either one
• ~6.4 kW ~= 25 miles in an hour, BMW i3-REx
• ~40 kW ~= 80 miles in half an hour, BMW i3-REx CCS

If I am parked for an hour doing something else, carpe diem, and snag a charge. But if I were trying to go cross country, using 40 kW CCS it would take:

• 1:10 hh:mm -> @70 mph (an overly optimistic rate)
• 0:30 hh:mm -> charge back to 80 miles
• 1:40 hh:mm to go 80 miles or 47 mph block-to-block

Understand I'm OK with snagging a charging opportunity on a cross country trip but gas refueling time is so much shorter, I don't spend a lot of time hunting down charging stations ... unless I'm doing something else like a meal, appointment, or sleep.

Bob Wilson

 

Bob, all the electrical arrangements you list are single phase. They're still single phase whether or not they have one or two hot legs. Split phase is just a way of attaining two voltages, both single phase, with the minimum of conductors used. Two of three phases is a misnomer--it's two legs of 3 phase--and still single phase. "Both phases" is not two phase power, that was used a hundred years ago (which needed four hot wires). "Both phases" is still single phase connected across two hot legs. The power coming into our homes doesn't have two phases.

If displayed on an oscilloscope, all the power mentioned above would show a single sine wave. Three phase power shows three sine waves 120° apart. The antique 2 phase power had two sine waves 90° & 270° apart.

 

I didn't want to jump into vector math which is how I see the various circuit configurations. So in the USA, each "normal" leg is 120VAC:

• 120VAC - one leg
• 240VAC - two legs 180 degrees apart
• 210VAC - two legs 120 degrees apart

By "normal" I am excluding power motors, heaters, industrial machinery, e.t.c. We talking about circuits that power lights and light-duty appliances and such.

Bob Wilson