[davideous]

Does any electric car have an option where you can place a portable gasoline generator in the frunk and then trickle charge the battery while you drive on a road trip (with appropriate venting of exhaust).

If not, why not?

I've seen very small, quiet gasoline generators. I would think this could solve this problem easily at the expense of a small amount of storage space.

[woofyman]

You’re describing a plug in hybrid or a serial hybrid like the Chevy Volt.

[davideous]

Yes, that's the effect. But I'd only have to carry the generator portion when needed for a road trip. You could perhaps even rent it only when you need.

Even if the generator was in a small trailer, that would provide the range freedom without loosing the storage space (and help with venting/cooling/noise).

[smileysteve]

> Even if the generator was in a small trailer

This has been done; but the small trailer also adds significant friction and aerodynamic drag. It also adds complexity in driving and maintenance.

[bluGill]

True, except the road trip case is also the case where you want more cargo capacity than is standard. A rental trailer for one week that lets my wife pack the kitchen sink actually makes sense.

[pkaye]

At that point might as well just rent an gasoline engine car.

[pitaj]

Except the engine isn't always there as taking up extra space and weight.

[saalweachter]

Weight probably isn't a problem - a Chevy Volt weighs a lot less than a Tesla S.

You don't even save much by keeping the gas tank mostly empty when you aren't expecting to need it -- the gas weighs ~6 lbs / gallon, so you might save 50 lbs by keeping the tank on 1/4 when you aren't planning to drive past the battery range.

Think about it this way: batteries are really heavy, and the Tesla has like 5x more battery capacity than a Volt. Meanwhile, if you're mostly making short trips, you're hauling around 3/4 of those heavy, heavy batteries as a contingency.

[semi-extrinsic]

BMW i3 range extender does exactly this.

[ghaff]

Not portable generators--which you'd really want built in for various safety and venting reasons. But you're basically describing a plug-in hybrid. The case against these is that you still carry over at least some of the complexity/maintenance of having an ICE.

[driverdan]

A small generator puts out less power than the car consumes. It would extend the trip but not solve the problem.

As others have said, it's more practical to have a purpose built hybrid.

[bluGill]

You don't need much power to keep a car going on the freeway. If I can extend my drive from 200 miles to 700 miles before I have to stop and recharge - well that is as far as a human can drive in a day anyway (many humans have driven farther - it wasn't safe they were just lucky).

[dsfyu404ed]

It doesn't take much energy to keep a modern car moving at highway speed. With regenerative braking and a limited top speed a small generator should be able to keep the car moving well enough.

[pitaj]

I've thought about this, too. It can't be that difficult to do, can it? Maybe it's illegal under current regulatory systems.

[smileysteve]

building a tiny engine that runs efficiently and produces enough meaningful electricity to make up for its weight is difficult.

From a regulatory standpoint, yes, fuel systems would be regulated in this design.

[pitaj]

The engine wouldn't need to be especially efficient; it's purpose is to extend range, not to be the main charging apparatus.