Electric car range extending trailers

[Fledermaus]

This is not a new idea, but I haven't seen anyone bring this up at DU. If or when electric cars move into the market place, I believe, we will see these things as well. Its not hard to imagine a family owning several EVs and one range extending trailer, and or perhaps U-Haul will rent them.

The Long Ranger range extending trailer converts an electric vehicle to hybrid mode for long trips. The efficient, high specific-output, gasoline fueled, trailer-mounted generator maintains battery charge, allowing unlimited driving range at speeds up to 75 mph.

The Long Ranger is proven over more than 20,000 highway miles. 20-kW DC output allows sustained high speed driving without range restrictions. Emissions are controlled with a closed loop fuel control system and a zero evaporative-emissions sealed fuel tank.

http://www.hawkins.info/files/rxt-g_acp_long_ranger_stats_data.pdf

www.acpropulsion.com/company/history.php

[katusha]

1. could it also act as emergency generator

for the home in the event of a power outage? that would be two birds with one stone.

[Fledermaus]

8. Gosh, yes...or even a small combined power and heat unit.

It could provide power and heat for a home.

[ConcernedCanuk]

2. Makes sense in a reverse sorta way. My father made us a special camping/food/cook trailer

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.
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that we would hook on for our yearly month-long camping trips.

So adding a fuel/energy trailer to save cab room for occupants/luggage is not a far stretch.

Just hook on the "energy" trailer for long trips.

I think it's an EXCELLENT idea that can be incorporated to a grid system to help out with our ever increasing power outages.

And for us guys(and gals) who love to take those trips to the bush . .

oh yeah . . .

[comtec]

3. My personal concern is that those generators are dirty

they spit out more crap than cars do.
if everyone went electric, and only say 10% of them did long trips, it would not be such a problem.
a set of extra batteries might be nice too.
I suppose if you built it to specifically run on chips oil (diesel) at least it would not be adding co2 like petrol does.

good idea tho, overall.

[tinrobot]

11. They don't have to be dirty.

The generators you get at Home Depot are dirty, but they don't have to meet the same standards as a vehicle.

Just like with a car engine, you could easily fine tune the engine in a towed generator for low emissions. Probably lower emissions because it would run over a very narrow range of speeds with a fixed load.

[phantom power]

4. That gives me an idea.

A roof-mounted battery pack. Something you could attach to a roof-rack.

[GliderGuider]

5. Or you could go the other direction entirely:

The http://en.wikipedia.org/wiki/Bennett_buggy">Bennett Buggy was a term used in Canada during the Great Depression to describe a car which had its engine and windows taken out and was pulled by a horse. In the United States, such vehicles were known as Hoover wagons, and named after then-President Herbert Hoover.

Timely, eh?

[phantom power]

6. From "horseless carriage" to "engineless car."

The circle is now complete, young skywalker.

[XemaSab]

7. .

[tinrobot]

10. Probably too heavy.

A heavy battery on the roof of a car would make the car much more likely to roll.

[kristopher]

9. This idea is a non-starter

The primary reason for this approach is found in the energy density of the storage technology - in this case the weight of the batteries versus the amount of energy they hold. The more batteries we add to a vehicle the more it weighs and the more energy it requires to move the entire unit, so there is a steady decline in the mileage performance as more batteries are added to extend range.
Since most vehicles travel less than 40 miles daily, all things being equal to past technologies, it makes sense to use the trailer approach to extend range; however all things are not equal to past technologies.

A lead acid battery pack weighing 1100 pounds can provide enough juice to go 100 miles; a nickel metal hydride battery pack weighing 1100 pounds can go about 200 miles; and a lithium ion battery pack weighing 1100 pounds can go about 300 miles.

Next take into account advances in lithium technology (already proved in benchtop tests and working through the process of developing manufacturing techniques) that deliver an 8X to 10X improvement in energy density over todays best marketed technology. This is expected to take 5-8 years to bring to market.

Currently lithium batteries are extremely expensive, but that is expected to change as demand increases and more manufacturing capacity is built. In the meantime, the series hybrid approach seems to be more cost effective than the trailering option.


http://stargate.uwaterloo.ca/~jzelek/teaching/syde361/batteriesPrimer.pdf


Edited to add: Oops!!! That will teach me to read more carefully. I didn't erase the above post because it is accurate as it pertains to battery trailers, which is another idea on the drawing boards. This might be a good step in the process after all.

[Fledermaus]

17. Gosh, the Chief Technical Officer of Tesal Motors built two IC pusher trailers for his

own person electric car.

http://www.straubel.com/index.htm

[kristopher]

18. And I built a beautiful gatehouse out of salvaged wood.

That doesn't mean either is an economically viable proposition.

[Fledermaus]

19. You think so?

[kristopher]

20. Yes, I do, the series hybrid makes it obsolete. But what about

But what about light duty trucks that are designed like a tractor trailer? The trailered bed of the truck has auxiliary batteries and motors while the "tractor" has a set of small rear wheels that are lifted off the road by coupling with the trailer. When not hauling cargo the extra weight is left behind. It could be designed either as a sort of fifth wheel configuration or with a bayonet style coupling that locks the two components into a single unit.

One important point that is getting in the way of a lot of ideas is the rapidity with which technology is advancing. Especially in the next 10 years I think we are going to see some advances in energy storage technologies that are going to push design change.

[Fledermaus]

21. Your funny, its like the less you know the more noise you make.

[Fledermaus]

22. On the occasions its needed, adding a trailer with an engine, turns an electric car into a hybrid.

Allowing a short range electric vehicle to have unlimited range. Its a proven fact. They exists today. There cheap and easy to build.

Conversion Cost $500 estimated. Car was $200, steel about $100, new radiator about $100, probably about $100 more in wireing and connectors.

This thing is remarkably easy to use. Once connected to the EV, it is started by switching on a toggle in the EV, then turning the EV's ignition switch to "start". Once towed to a speed over 25 mph, the OEM cruise control can be activated, and the trailer begins pushing the EV. The sensation is basiclly like coasting, except you can coast uphill. :^)

This adds a whole new utility to my EV (see WebPage ) I can now take it out of town when requested for EV displays.



http://www.evalbum.com/753

[ProgressiveProfessor]

12. Don't forget this will be a PITA to park in anything other than suburbia or rural areas

[Fledermaus]

13. Gosh, AC Propulsion thought of that. Check out this video

The trailer has an inboard computer and keeps the trailer directly behind the car when backing up.

http://www.youtube.com/watch?v=fN8g3bcU7ZM

[ProgressiveProfessor]

14. Its not the backing up, its the length of the space and room to turn

Most people eventually can be taught to back a trailer properly

[kristopher]

15. The trailer is extremely short and difficult to see.

The shorter the trailer in relation to the towing vehicle, the more difficult it is back up. Extreme precision would be required.

However I don't think this issue would be the determining factor on whether the product is successful or not. More importantly is the fact that series hybrids package the concept better.

[Fledermaus]

16. The engine only needs to be big enough to supply cruising power on the highway.

The amount of power needed is quite small even for a large car. The engine is small. Therefore, the trailer is small. The amount of drag limits the maximum cruising speed.

The primary requirement for an RXT power unit is the ability to sustain battery charge continuously. The RXT power output must match the EV road load at the desired cruising speed. If output is below road load, the battery will eventually be discharged, necessitating a lengthy stop for charging. For efficient, small-to medium size EVs, RXT output of 15 to 25 kW is necessary to provide comfortable freeway cruising.

Size and weight critically affect the usability of the RXT. Electric propulsion is well-suited for compact-size vehicles, so the RXT must be towable by such vehicles. It must also be easy to connect and easy to store if it is to provide acceptable convenience for the user. To achieve these objectives, a weight target of 150 kg was established.

The RXT, as developed, meets the highway power requirements of a wide range of EVs (Fig. 4). The 20 kW RXT output will propel large or less efficient EVs at a sustainable 100 kph. Smaller or more efficient EVs can sustain speeds of 130 kph or higher.

http://www.bilmuh.gyte.edu.tr/gokturk/hybrid/rangeextender.pdf

[Kolesar]

23. One could rent a gasoline-powered car when they need to drive a long distance, too

That might be cheaper than buying and financing a generator-trailer.

If I had one of those trailers, I would put my bicycles on top of it.