> […] but there can also be a significant benefit from allowing the ICE to remain in the RPM "sweet spot" rather than moving around a larger range.

Which is why I'm surprised electric cars with range extenders aren't a bigger thing:

* https://en.wikipedia.org/wiki/Range_extender

Have the powertrain be all-electric, and have a battery pack, but for those with range anxiety have a small generator as an option that would go in the frunk (front truck). A (proverbial) small Honda EU2200i would be less maintenance than a traditional engine.

The EU2200i can sustain 15 amps. That charges most EVs at something like a few miles of range per hour. The biggest one that’s small enough for a frunk is the 3200i, which still only sustains 21.7 amps - plus, that’s from an L5-30R socket, so you’d need an adapter for the EV, and a custom chip to limit charging current below that, since the ones I’ve seen for that socket assume they can pull 24 amps.

Re: maintenance, small engines typically are pretty needy. That one wants an oil change, spark plug gap adjustment, and spark arrestor cleaning every 100 hours of use. The latter two are only usage-based, but the oil is time-based as well (6 months) since it oxidizes, and suffers from fuel dilution. Then there’s the fuel: god help you if you put ethanol gas into a small engine and let it sit for any period of time. It’s often difficult to find E0 fuel, and while there are external fuel tanks for generators that can hold quite a bit, they also tend to vent vapor in the heat (as does any tank, including a car’s), which is unpleasant when it’s in your frunk.

Finally, engines of all kinds really don’t like being left sitting for months on end unless prepared to do so. Generally you want to run them monthly, getting them up to operating temperature, putting a load on them for a bit to fully exercise all components.

I say all this because I have an EU2200i and dearly love it, but am also painfully aware of its limitations and needs. I got it when I lived in Texas because the power outages were getting to be absurd, and my house wasn’t plumbed for natural gas, so a whole-house was out of the question. The 2200i was plenty to power two fridges, a deep freezer, TV, fans, and my server rack. I got really good at quickly running extension cords (which is a whole other discussion on ensuring proper amperage ratings and calculating voltage drop, something most people ignore).

For a Honda 2.2kW to aid with range anxiety, you'd have to split range anxiety into two categories and I think it only addresses the second/lesser of the two.

Assume the car gets 4 miles per kWh delivered and the charging cycle is 90% efficient (measured from generator output). The 2.2kW generator can add 8 miles/hour of generator runtime (2.2 kW * 0.9 * 4 miles/kWh).

For range anxiety of the form "we're driving to a destination pretty far away and I'm not sure we can get there", that's not very helpful. For range anxiety of "I'm driving to a destination that's over half my range and then going to spend a full day [or overnight] there, but I'm not sure there will be working chargers available there", charging 8 mph times 8-10 hours is very helpful.

Worrying about being stuck in the boondocks without a charger is addressed by an 8 mph on-board charger, but I think that's the less common form of range anxiety.

The Chevy Volt range extender was 75kW; the i3's was 26.6kW. 2.2kW is literally an order of magnitude too small to replace those.

BMW tried that with the i3, it wasn't particularly popular. An engine, fuel system and a generator are all relatively complex additions compared to just putting the same cost and vehicle space into more batteries, and the public charging networks are definitely up to the task by now (having been EV-only for almost 5 years now).

The newer London black cabs do that

> The LEVC TX is powered by a full-electric hybrid drivetrain. It drives in full-electric mode all the time, but is recharged by an 81-horsepower (60 kW; 82 PS) Volvo-sourced 1.5-litre turbocharged three-cylinder petrol engine.

Diesel REX vans would be a MASSIVE hit if a company would just decide to start making them.

The #1 reason for (european) companies not buying full EV vans is range, they need to drive a LOT during the day.

REX would solve that with minimal emissions. And depending on the battery size, they could drive on full EV in city centres and only allow the REX to charge the battery during longer drives.

The BMW i3 REX is a fantastic car, if you can find one, buy it.

Range anxiety seems to go away after your first week of EV driving.

Maybe because people don't want to have oil changes, emission checks, exhaust gas etc. on their EV. If they really need a long range, they will probably just buy a combustion engine car.

One 120V 2.2kW generator isn’t going do much at all. It’s really actually 1.8kW which is 15A at 120V.

You’d need to tow around a 7.2kW 240V for 30A at 240V (more likely a 14.4kW generator for 240V 60A).

Using the small Honda inverter generator (which is amazing for plenty of stuff!) is akin to covering your car in solar panels to get range extension, the math just doesn’t work out.