Battery, ICE, Hybrid: What About Temporary Mixes?


I was thinking about all the different variants of battery powered and hybrid cars, and thinking about the BMW i3 REX, which is a medium range PHEV that uses a small, cheap motorcycle engine to drive a generator. I think there might be two new types of semi-hybrid cars with this approach, so I wrote up a summary of all the types, and where the new modes fit it, particularly a plan to make cars with a receiver in which a temporary generator module can be placed.

See my article at Battery, ICE, Hybrid: What About Temporary Mixes?


How about an ethanol-fueled fuel cell as an add-on range extender module? Maybe less of a problem with exhaust and cooling? How would this compare weight, volume, and efficiency wise to an ICE generator?

One could imagine alternate modules, as long as they fit in whatever form factor was decided. The external port can have exhaust and fuel and possibly a cooling air intake (easy on the front, less so on side and rear) and electrical connection would be inside. Cooling is a different question. Battery modules might need access to the battery cooling system of the vehicle which means another hookup. This generator might run when the vehicle is stopped, which complicates the cooling question.

You could even have a hydrogen fuel cell if you can find the room to have the hydrogen tank. The but reason you wouldn't is the whole point is to go off the beaten path, and you won't find hydrogen or pure ethanol in those places, so what's the value?

I think we're going to see more usage of different cars for different purposes in the future. BEVs must be great if you can charge them in places where you would be parked anyway. They must be a major pain otherwise. Tesla (it's mainly Tesla leading the way) keeps extending the battery range further and further to try to minimize the times when charging is an issue, and they've built a large supercharger network to make the painful a little less painful, but that has caused the cars to be significantly more expensive than they have to be. Batteries are not as insanely expensive as they were several years ago, but they're still expensive, and they'd be even more expensive if a greater fraction of the world needed them right now. (They'd also be much more expensive if we stopped buying them and parts of them from countries with abysmal records on workers rights and pollution, which we probably should do.)

I think it'd be feasible today to convince a lot of people to abandon their owned or long-term-leased vehicles and move to shorter term rentals. It'll be easier once those cars can drive themselves to the person renting them, but models like Zipcar and such are already having limited success today, and I think with some tweaks to their business model they could be having much more significant success even before headless operation arrives.

In fact, I'm trying to figure out a way to get my ideas in this space funded. I'm surprised no one is doing it right, and I think it's a huge opportunity.

As I have written in other places, the best answer for those buying a non-Tesla electric car (and sometimes even a Telsa) when taking road trips is to use a rental car.

However, people resist that. One reason they resist it is they love driving their zippy electric car so much they don't want to give it up on their fun road trips.

I also think the subscription model is a good way to go to allow most of us to use smaller cheaper shorter range electric cars most of the time. A pool of larger long range electric, ICE or hybrid could be used for longer range trips.
Holiday season still poses a problem here as obviously demand for longer range, and probably ICE vehicles peaks. As Brad has stated previously charging electric in holiday season may be an issue.

Maybe closer examination of the most likely use cases would help here.

I go 500 miles to my main holiday destination where I base myself and do only short trips from there.

I go 300 miles to my first stop, stay a day for some activity (grand canyon hike say) then do a similar distance each subsequent travel day.

To me the electric trailer seems to suit both these long range scenarios very well.
The requirement to back and park the trailer would be lessened if you pick up and drop them off at a charging station. There is no need to take it on your shorter trips.

There is also the option to self power the trailer if the vehicle is low powered.

The last wrinkle is that vehicle size is also an issue at peak season, a city car not having the space required for tents/family. Perhaps a powered trailer with luggage space could also help here, but at the cost of having to take it for your whole trip.

Rent a Tesla Cybertruck with 350+ mile range, use a destination charger at your stopping locations, and you're all set?

That truck is probably going to be pretty good for road trips. I do wonder how they'll get all the cameras to work when towing a trailer. Can they forego the rear camera? What steps will need to be taken to make the car aware of the dimensions of the trailer in order to adjust driving? (These problems could also apply when the truck is loaded in certain ways.) Maybe you'll just have to do without full self-driving in these situations? That would be disappointing.

Peak holiday driving days are going to be tough, as the driving needs are very different from the usual. Even this will change quite a bit with self-driving cars, though, as people will be able to drive overnight while they sleep. And the cars only need to be self-driving on the highway as long as they can park themselves at a rest stop.

In the longer term luggage can just be carried in a separate vehicle that's completely driverless, but the truly driverless vehicle that is accessible to the average individual is probably quite a long way off.

Once we've reached that point, it'd be possible to refuel a car (with gas or electric) without even stopping. The trailer just drives itself, does a rendezvous with the moving vehicle, refuels the vehicle, then detaches and drives away to the nearest home base (which probably won't be the same as the one it came from). A bit wasteful, sure, but very convenient. (Probably less wasteful that carrying the trailer around all the time. Maybe even less wasteful than driving around 365 days a year with a battery capacity that you only need 10 days a year.)

One option would be to put a camera on the back of what you're towing. You may recall an earlier article I had about how trailer and electric tow vehicle might become integrated, sharing power. Sharing sensors also makes sense -- indeed all you actually want between trailer and tow vehicle is a power line and a single data line, though a cooling line could also have value.

Recharge while moving seems a bit extreme. Inefficient as you say (power going in and out of two batteries and the power to move the charge vehicle) but also fairly pricey.

Now charging when stopped requires that people want to take breaks. In an RV style vehicle you may be less inclined to need those.

There is an argument that for most people, a cross country rv trip is not efficient. Travel to a destination in an efficient way, then rent an RV there. But people do like to own RVs, and some even like to do very long haul trips. But those people rarely want to travel full-nonstop. The whole point is to stop and smell the roses.

For sleeper vehicles, it should be possible to program them to come to a very gentle stop at an automatic charging station, with gentle restart.

If there is demand for charge while driving, of course people have often talked about roads with built in charging (inductive or pantograph.) The main problem is that this is very expensive, and makes the roads much more expensive to maintain. Also a lot of power to deliver. One wonders if you could make special charging lanes, a special lane just a few miles long where you slow to maybe 25mph and connect to a set of charging rails on the side of the road. The faster you want to go the longer it is, and the more expensive. You would need whatever connects to the rails from the car to be cheap and highly reliable. The car must be a robot while driving next to the power rails so that it does not deviate.

I'm thinking about ad-hoc towing here. Eventually maybe there will be a Tesla-brand utility trailer, and a Tesla-brand cement mixer trailer, and a Tesla-brand boat trailer, and a Tesla-brand all-the-stuff-I-can't-think-of-cause-I've-never-owned-a-pickup-truck trailer. But in the mean time, if people are going to buy a Tesla pickup truck, presumably a lot of them have particular towing needs (and have already invested in one or more trailers). Maybe you will be able to just find a spot and self-install a camera there and the truck will be smart enough to align everything virtually. I think it'll be a challenge, though, and it's not just the camera. The truck will need to be aware of the dimensions of the trailer; it'll need to be aware of how the trailer behaves around curves. Your driving has to change when you're driving with a trailer. Most humans are great at adapting to the changes. For an ADAS or self-driving vehicle, I'm sure it'll be possible, but it's going to probably take a bit of engineering.

Yeah, recharging while moving will be pricey, at least compared to charging at home. People tend to be willing to spend more for convenience when they're on a semi-annual vacation, though. Driving 500+ miles isn't cheap.

Charging when stopped requires that people want to take breaks. But more than that, it requires that people want to take breaks at a charging location spot for close to the length of time they have to charge. If (when) charging takes 10 minutes, and there's a bathroom nearby, that's not so bad. When it takes an hour or more, that sucks.

I don't see roads with built-in charging happening. There is demand for charge while driving, where and when you want it. If you have to plan your trip around being in the right place at the right time, it defeats the whole thing.

I guess the main argument against charging while driving is that by the time the technology exists for it to happen there will probably be superduperchargers that can charge in just a few minutes.

While fast charging may well be coming, it doesn't have to. However, if there is charging every 30 miles, and it has decent food, then anybody can charge during meals by accepting a modest compromise on meal choice. Those with RV trailers, of course, can and will cook and eat in their trailers while charging, and that is often their intention so the compromise is not so great, at least for lunch. (Some do prefer to make dinner at their campsite.)

One way to improve that is to put dining tables at charging stations. Not restaurants (that's nice) but simply places to eat. Then you order food from a very wide variety of restaurants, who have it plated on your table by the time you plug in for charging. Delivery robots make that even easier.

In this case, 40 minute charging is quite acceptable. Motorhome drivers may eat a bit while driving, but usually they stop and they don't cook while driving.

One could make a camera module that goes on the back of any trailer fairly easily, at some location with power. An ideal location would be the brake lights of old school trailers, which get more than enough watts of power with the existing wiring. All you do is run a data protocol over those DC wires to a replacement brake light or turn signal. The replacement light contains the camera, and a new LED light which is switched digitally rather than by the voltage which is now always on. You can do enough megabits over the copper to transmit the video.

It may be a modest compromise for some. It may be a more significant compromise for others. Some might think it's worth it. Others will not.

One thing I think would make it less of a compromise would be, instead of bringing "decent food" to a supercharger station, instead having charging available where people happen to go to eat anyway.

When people stop for lunch, they can top off their batteries. They can reserve the parking spot shortly in advance while on the road, and they don't have to worry about having to move their car 30 minutes into their meal. They don't have to time lunch to be at the same time they need power. They just get as much power as they can while they're stopped anyway. If they didn't get quite enough, they can stop at a supercharger station later, and since they topped up at lunch they might only need a little bit of extra charge to get them to their destination, where there will be another destination charger, if not where they sleep for the night then maybe where they eat breakfast in the morning.

Supercharger stations, as in places where the primary focus is on getting power, are needed in order to greatly reduce range anxiety. It's important to know that you won't be completely stranded if things don't go right. But I think destination chargers, as in places where the primary focus is on something other than charging, and you can charge right where you happen to be parked anyway, are the key to making EVs acceptable to most people (who aren't going to be willing to make a "modest compromise" just to score virtue signalling points with their friends).

As an added bonus, once you have a huge destination charger network, you can send people to destination chargers on peak days when the superchargers fill up.

You're right, of course, that (much) fast(er) charging doesn't have to come. It probably does have to come if EVs are going to be adopted by the vast majority of the population, though. Moreover, it's hard to imagine it not happening. There's no fundamental limit that we're anywhere close to reaching. It'll be more expensive, but it's very useful in the types of situations where spending extra is expected anyway. Vacations. Emergencies. Driving long distances with small children (which is usually similar to a combination of "vacation" and "emergency").

Well, sure, if you can afford to install high speed chargers at every restaurant, then fantastic. High speed chargers are quite expensive, and because of the need to bring in megawatts of power, they will continue to be. In effect, 99% of Tesla's are located at restaurant clusters, but they are the sort of restaurant clusters I don't find very appealing though which have "appealed" to interstate travelers for some time -- fast food.

The restaurant business is not sufficient margin to install this sort of stuff, not today, not unless demand gets very solid.

However, in a much simpler charging deployment -- every 50 miles along the road, not every restaurant -- people can charge pretty much any time they want, when they feel like eating. If they can get a wide selection of restaurants to deliver to the charging "restaurant" then they can eat what they want, when they want it, just not in the physical restaurant, but instead in the building at the charger with tables.

Regular level 2 charging is not sufficient for travel charging. It's only really useful for night charging.

We're not talking about today. We're talking about the future.

The restaurant shouldn't have to pay a penny. In fact, the restaurant would more likely receive revenue, like when they allow someone to install a vending machine. The cost of the charging station would be paid by the people who use it.

And people will be willing to pay, quite a bit, so that they can eat in a restaurant rather than eating delivery in their car. If 3 customers a day pay $5 each for a convenience fee, you can pay for a DC fast charger in about 5 years, and that's without factoring in the fact that the technology is going to get better over time. That $5 fee probably wouldn't be much more than the delivery fee would be to get lukewarm restaurant food delivered to your car. Try not to make too many crumbs.

Maybe you hire a trailer with a generator in it for long journeys, with additional luggage space as a bonus. Maybe something more efficient than a typical diesel generator like a sterling engine or a solid oxide fuel cell.

I have written about trailers. They have advantages -- a little more universal, easier to cool etc. But they also make it harder to move around, park and back up (though having their own electric motors could help with that.) They add drag and weight and would be a lot larger than a small generator module.

Charging when stopped requires that people want to take breaks. But more than that, it requires that people want to take breaks at a charging location spot for close to the length of time they have to charge. If (when) charging takes 10 minutes, and there's a bathroom nearby, that's not so bad. When it takes an hour or more, that sucks.

Today, with charging stations further apart, you don't get much choice in your station. In the future that will change. You do have to eat, and in such a world, there will be a station around the time that you want to eat, and so you charge there. It is a compromise, to be sure -- particularly today in terms of choice of restaurant -- but right now most Tesla owners seem pretty good with it, willing to accept that compromise in exchange for not having to accept the compromises of a gasoline vehicle (expensive, polluting fuel, high maintenance, lack of fun to drive for the price etc.)

It's compromise vs. compromise. If good meal choice is absolutely essential to you, you won't like the current Tesla supercharger network. However a growing number of people are willing to take that trade off.

BTW, meal choice is important to me, BTW. So I hope to see this problem get fixed through a variety of approaches. But the advantages of my electric car are already important.

Of course, with a rentable generator module and more common charging in hotels, one would not longer need to make any meal compromises, and if the chargers were not suitable to your meal choice, you could have that, at a cost in gasoline burning.

The timing issue isn't whether or not there's a station available when you want to eat do much as whether or not you want to eat when you need to charge. 300 miles of range goes by in 4 hours at 75 miles per hour, and range goes down at those speeds (, so it's likely even less than that. If you charge and eat at noon that would put your next charge/meal at 4PM, which is too early.

Maybe there will be traffic so that your dinner can be at a more reasonable time. But you won't know in advance, so it's hard to plan your trip around assuming there will be traffic.

I'm not sure if there have been studies on how willing Tesla owners are to accept that. I'm also not sure how common it is for a Tesla owner to drive their Tesla over 300 miles. It's probably rare enough for most people that they're willing to accept the significant hassle in exchange for the benefits they see in a Tesla.

I bet a lot of people also solve the problem by using a different car for long trips. That's how a few family members of mine have dealt with it. I never get to see their Teslas at family reunions, because they take the car of the other spouse. I'm not sure if that's common or anecdotal, though.

500 miles of range at full highway speed (over 6.5 hours at 75mph) would probably make the problem much less of a problem, and I wouldn't be surprised to see that eventually. And, of course, much faster charging would largely solve the problem.

Yes, if you are doing a non-stop barrel down the highway you will eat a bit early. Since you take 40-60 minutes for eat/charge, if you leave at 9, you charge at 1pm, then are doing dinner charging at 6pm. Not great but not too far off the schedule of most people. A bit worse with shorter range.

So obviously Tesla owners do accept this. Clearly it's not a first choice. But drive-all-day is not common for most people, it's something you do a few days a year. For me, a "road trip" involves enjoying the journey -- if I just want to get somewhere I fly. As such the timing is a little easier.

Tesla added one nice feature, which is why you are charging you can watch streaming video like Netflix etc. Now, when I am at home, I often will watch TV for an hour or two in a day, and most people watch more. However, I will say I don't usually watch any TV on a trip, so this is also a compromise. Sound system is OK, screen not quite as good. I also see people on their phones and all the usual things, but at the rural chargers only a small minority are in their cars. Most are eating or shopping.

When chargers are frequent, though, there is another option for timing your meal, which is to pick up a short 10 minute charge when you need to pee. With Tesla's 250kw chargers, as they are deployed, a 5 minute charge can give you another 80 miles. So, if you need a charge at 5pm, and it's not time for dinner, just pick up another 80-120 miles at a pee break, and do your 10%-90% charge when it's really time for dinner. Of course 250kw charging is quite rare today, but new networks will be this fast.

I'm not sure what you mean by "obviously Tesla owners do accept this."

The 10 minute bathroom-break-charge-up sounds like a good idea to reduce the hassle considerably.

I mean that vast numbers of Tesla owners are taking road trips, and accepting the limitations of the current supercharging network today, rather than driving a rental car (or their gasoline car, which they often still have.)

Vast numbers? How many Tesla owners take how many road trips that exceed their range?

It's not obvious that the numbers are vast. Plus, many of the people who have done it probably will think twice before doing it again after what happened over the Thanksgiving holiday.

The people I know who have Teslas use their spouses' gasoline cars if they have to drive farther than their range. Or they take a plane and use a rental car. But that's anecdotal. If you have some stats that show these vast numbers, I'll believe that over my anecdotes.

It still won't be obvious, though.

All the people at rural superchargers are taking road trips that exceed their range, at least in places that effectively have no locals.

That lines on Thanksgiving appear to be more about the weather than simply the busy traffic day, but of course that did not help. In the end, only 2 reports of that surfaced, though I am sure there were small lines in other places. But I scanned all of northern California (you can do that on the car screen) and there did not appear to be much else in the way of trouble that weekend.

The idea of an electric car you can do a long road trip in is a fairly new one. It does work -- with some limitations -- and a fair number of people are doing it. What fraction of owners, only Tesla knows.

I don't think it's true that "All the people at rural superchargers are taking road trips that exceed their range, at least in places that effectively have no locals." Even if it were, I don't know how many that is. And I don't know if the people doing that find it acceptable.

I don't think it matters if the Thanksgiving problems were caused by weather, by traffic, or both. It must have been awful to deal with.

Hopefully Tesla will be able to increase the number of stations fast enough to make it a very rare occurrence. I'm not sure where they are in terms of revenue and expenses there. It has to be difficult for them, as the demand is extremely variable. I suppose in a sense the "free supercharging" model had advantages. Presumably most of their costs are fixed rather than usage-based. So letting people charge for free during non-busy times is relatively low cost.

Well, you obviously can increase the number of chargers to have no waits at peak times, but only by a lot of overprovisioning, which is very expensive, and must be paid for (by customers in the end.)

I do think it's true that the vast majority of those charging at Kettleman City, which in spite of the name has no city, are not locals. I mean the vast, vast, vast majority.

I hope it'll be reasonably cost effective to have so many supercharger stations that long waits are rare. Yes, more stations means paying more, but I'd say there's a lot of room for higher supercharger prices, and the cost of the equipment itself is probably not the main cost.

Kettleman City looks like it's close enough to halfway between San Francisco and Los Angeles that I suppose it is fairly likely that many people are using that to make that trip. On the other hand, they might just be on their way home to Fresno after spending the day at the beach at Morro Bay.

Putting some level 2 destination chargers at the beach parking spots there might cut down on the need to have as many superchargers. It'd save a lot of hassle, too. Charging where you happen to be parked anyway is the way to go.

Anybody doing a long road trip (ie. one longer than 80% of their car's range) is what the supercharger is for, and not a local person using it to drive around town. When you just want to drive around town, home (or office) charging is all you need. Supercharging is for when you want to do more than that.

Level 2 charging is possible at a beach because it's a place people go for many hours, but it has a strange inefficiency because it requires occupying the land for a long time. To be useful, you want to spend at least 2 hours at the charger, but places you spend 2 hours are often places you spend much more than 2 hours, so you actually fill up and then block the spot. One sees this in work parking lots -- people plug in only needing an hour, but they stay all day. This is notable for PHEVs that can't charge for more than 1-2 hours. They actually need the power more than a Tesla does, perversely, because the Tesla can make it home on electricity, but the PHEV can only make it home on gasoline, and if you want to not burn gasoline, the PHEV needs the electricity more.

I have proposed some answers. One useful idea for all-day lots would be charging units at the intersection of 4 spaces (or a block of 8) with multiple cords able to reach all the spaces, but not necessarily enough power to run all the cords. Cords are not cheap but a lot cheaper than whole stations and more megawatts of service.

But in reality, it's complex for something we don't really need, namely level 2 charging in parking lots.

One option that could make sense though, and could be done this year I suspect, would be for Teslas to be able to move within a parking lot to charging stations as needed. So park your Tesla in the lot, and it takes its turn at a level 2 station for its share of the day's schedule. This requires that "summon" be a fair bit smarter but I see that as technologically doable. Plugging and unplugging is still done by humans (the humans arriving or picking up cars are required to go swap plugs for others if they want to get any charging) Later you can have robotic plug in. Sadly, the Tesla is designed with the charge plug coming in from the side. If there were a charge socket on the front or back it would be possible for the car to plug itself in, because the car could move in the direction needed for insertion and removal of the plug.

Level 2 chargers are fairly cheap. Sure, some people will "block the spot" for 6 hours even though they only use it for 2. So what? It won't be nearly as wasteful as having a level 2 charger in your garage, which is only ever used by a single person.

You're right that your "answers" are complex for something we don't really need. But what we don't really need is for chargers to be used all the time when someone is parked there. We definitely do need level 2 charging in parking lots. A lot of it, all over the place. It's very convenient compared to just about everything else.

Yes, a Tesla could, maybe within a year or two, move within a parking lot to charging stations as needed. With the plugging still needing to be done by humans, it's not all that useful (or it's very inconvenient). If level 2 stations were more expensive, it might be worth it to have a valet move the cars. But level 2 stations aren't that expensive, especially if they're not all in use at the same time. Moreover the demand for charging stations is still growing, so you don't really lose much by buying way more than you need today. You will need them in a few years. So in the meantime, you have enough to be a little bit wasteful, and let people park at them longer than they need to.

(Most of this doesn't apply to superchargers, of course. Superchargers are pretty expensive. One thing that does apply to superchargers is that demand for them is growing, so overprovisioning today is not so bad in the long run. But only if you have the capital to spend today, and Tesla is somewhat strapped for cash. Not as bad as they were 6 months ago, and maybe the situation will be even better in a year. But they do have to be careful about spending too much on things that won't pay off for several years.)

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