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Comment by drewg123 | Hacker News Reader

I'll probably get down-voted, but I really think best way to improve BEV range for road trips is towing a diesel or gas powered electric generator. Your car becomes like a plugin hybrid, except you don't have to deal with the weight, mess and complexity of an ICE drivetrain on a daily basis.

I can imagine an infrastructure where you rent one of these towed generators at a national chain when you depart, and drop it off at your destination. Similar to renting a U-Haul trailer.

I have a Tesla with a 100Khw battery and ~290mi of range. The only time I need more than 100mi of range in a day is when I'm taking a trip, which is not a daily thing. If such trailers were rentable for a trip, BEVs could have much smaller and lighter batteries. Eg, my car could be substantially cheaper and lighter.

I wish Tesla and other BEV cars would allow charging while driving.

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> towing a diesel or gas powered electric generator. Your car becomes like a plugin hybrid

The Hammerhead Eagle i-Thrust used this method. OK, it had the generator in the back so you were always carrying it about, but you know, baby steps and all that.

How about a trailer that contains a battery pack big enough to last your whole trip? Going 600 miles? 100kWh trailer. 1000 miles? 250kWh trailer.

Drop it off at uHaul when you get there, and pick up another one for the return trip.

Of course, a 250kWh battery pack would be a lot more expensive than a diesel generator, but it would involve much less maintenance and wouldn't risk disastrous user error.

> If such trailers were rentable for a trip, BEVs could have much smaller and lighter batteries. Eg, my car could be substantially cheaper and lighter.

hypothetically if this trailer solution existed, I still don't see people buying BEVs with smaller batteries. In general, most like the piece of mind of that range. Things happen - chargers break, power outage or you end up taking an unexpected trip or you spend some time at a friends home where you can't charge

Given that the charger networks are growing at a decent clip and average charging speeds continue increase, not many people would want to bother going to U-Haul before and after a trip when you could just stop for a bit on the way, have some coffee and stretch your legs

In short, it'd be such a niche product it would make little sense for auto manufactures in invest in it

Rivan does have plans to let you add a battery pack for the bed of the truck. I hope that comes out and someday other brands do the same

The BMW i3 REX is like that. It has a small petrol tank and ICE - which is used as a generator to power the traction battery.

It's fine, as far as it goes. But most of the time you're dragging around extra weight and there's more mechanically to go wrong. You also might not be able to use some roads when you're emitting fumes.

I don't understand why people are allergic to stopping at a rapid charger every 2 - 4 hours. Surely people need to stretch their legs or go to the loo?

Indeed.. I don't much care for solutions like the i3 rex. That's why I propose hauling around the charger only when needed.

Its not so much stopping every 2-4 hours that's the problem. If it was a 3-5 minute stop, it would be fine, but its a 20-40 minute stop (assuming no contention for chargers). I've taken many 900+ mile (each direction) road trips in my car. Charging generally ads about 25% to the overall elapsed time. The chargers (at least in the I95 corridor in the USA) are often not equipped with 24hr restrooms.

Well, why not form road trains with a truck sized generator.

You just schedule your route and an app shows you where to dock with the roadtrain.

You can also carry your meat body into an actual train, but I think this is not the point here.

That's an interesting concept, but the towed generator model also allows you to go "off grid" to rural areas without fast charging. Such areas would be unlikely to be a common enough destination for a roadtrain..

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