4 ms·

> The generator doesn't need to be large (and expensive) enough to be capable to drive from directly at highway speeds, but just enough to extend the range when

> The generator doesn't need to be large (and expensive) enough to be capable to drive from directly at highway speeds, but just enough to extend the range when needed. So you would need to park and let the generator slowly charge your car? Why not just charge the car at a charger at that point? Make the generator large enough so that it can generate enough power to directly run the electric motor for highway driving.

elcritch 4y ago
Yah I figure use a super charger. Maybe refill gas too. If you could save $20k I'd say it'd be worth the hassle on the occasional road trip. The main reason would be cost and weight. Full EV card are still too expensive for many. I'm guessing there's a sweet spot that'd be much cheaper than either but would provide more range when needed. But as the other commenter points out the ICE + 20 mile pack might win out on efficiency of scale.
- dahfizz 4y ago
  But why include the gas engine at all if it doesn't extend your highway range? Keep your small <100 mile battery pack, skip the extra cost and weight of an engine.
Schroedingersat 4y ago
A car only needs 10kW or so on average to do highway speeds, but you need peak power around 30kW at minimum (or about 70 to satisfy most people's expectations). You only need the generator to be able to extend the driving time to around 8 hours to cover 99% of use cases, so if your battery can do 2 hours then the generator only needs to produce 3/4 of the energy in the minimal case. What you are proposing would require the generator to be 3-20x as large as the alternative.
- deleted 4y ago
  [deleted]
- dahfizz 4y ago
  Sorry, maybe I was not clear. Assuming you are correct, I am saying the generator should produce 10kW of power, and OP is suggesting that the generator would generator < 10kW. I'm saying the generator should keep up with the energy demand of cruising on the highway.
  - Schroedingersat 4y ago
    You can get a range multiplier even below that. A car that uses 10kW average and has a 50km range is usable with a 7.5kW generator and stopping to charge every 200km. Knowing you have the ability to stop and charge or limp at 3/4ths speed to the next charger would allow more confidence pushing the boundaries. A small battery means a 15 minute break to charge every 2 hours is viable and not a deal breaker for someone who only needs range infrequently.

elcritch 4y ago

Yah I figure use a super charger. Maybe refill gas too. If you could save $20k I'd say it'd be worth the hassle on the occasional road trip. The main reason would be cost and weight. Full EV card are still too expensive for many. I'm guessing there's a sweet spot that'd be much cheaper than either but would provide more range when needed. But as the other commenter points out the ICE + 20 mile pack might win out on efficiency of scale.

dahfizz 4y ago
But why include the gas engine at all if it doesn't extend your highway range? Keep your small <100 mile battery pack, skip the extra cost and weight of an engine.

Schroedingersat 4y ago

A car only needs 10kW or so on average to do highway speeds, but you need peak power around 30kW at minimum (or about 70 to satisfy most people's expectations). You only need the generator to be able to extend the driving time to around 8 hours to cover 99% of use cases, so if your battery can do 2 hours then the generator only needs to produce 3/4 of the energy in the minimal case. What you are proposing would require the generator to be 3-20x as large as the alternative.

deleted 4y ago
[deleted]
dahfizz 4y ago
Sorry, maybe I was not clear. Assuming you are correct, I am saying the generator should produce 10kW of power, and OP is suggesting that the generator would generator < 10kW. I'm saying the generator should keep up with the energy demand of cruising on the highway.
- Schroedingersat 4y ago
  You can get a range multiplier even below that. A car that uses 10kW average and has a 50km range is usable with a 7.5kW generator and stopping to charge every 200km. Knowing you have the ability to stop and charge or limp at 3/4ths speed to the next charger would allow more confidence pushing the boundaries. A small battery means a 15 minute break to charge every 2 hours is viable and not a deal breaker for someone who only needs range infrequently.