I propose trailering an external battery pack behind hybrids that would permit the hybrid to run under electric power only for perhaps a short duration (< 100 miles). This pack could be charged off of the utility grid when it's not being used.

On long range trips, the hybrid would make far better use of the gas/electric motor combination. For short range trips, the trailer towed battery would extend the range sufficiently to eliminate the need for the gas engine to start.
-- BMCCUE, Nov 08 2005

On-Board Switchable Power Source http://www.evworld....ue&newsid=9896&url=
From the article: "CalCars' PRIUS+ project retrofits Toyota's Prius, the nation's most popular hybrid car, with a high-energy content battery, which becomes the vehicle's primary power source for local travel, eliminating the use of gasoline for short trips. For longer trips, the car can revert to conventional hybrid operation, which uses a combination of gasoline and battery power. The battery can be recharged at off-peak hours, further supporting energy conservation." [jurist, Nov 09 2005]

These things - battery trailers - seem to exist, or maybe people just thought about them in the early days of electric cars. Can't find a good link, though.

From one reference, I will suggest adding a solar panel to help recharge the thing.
-- DrCurry, Nov 08 2005


Why heavy batteries? Why not rubber bands?
-- RovinRobin, Nov 08 2005


I've seen the reverse of this - a straight electric car towing a small diesel generator.
-- BunsenHoneydew, Nov 08 2005


A company named Electro Energy Inc. has developed a prototype high-energy content battery for CalCars' Toyota PRIUS+ project. This battery is retrofit mounted on-board, rather than externally towed, but it allows the user to run exclusively off rechargeable battery power for the short trips that you describe, then revert to hybrid operation for longer trips. See the [link] for more details.
-- jurist, Nov 09 2005


I've read about the onboard conversions that utilize a larger battery bank and a tweak to the onboard engine management system. These are cool, but one would assume somewhat expensive.
-- BMCCUE, Nov 09 2005


But if it can be accomplished without great sacrifice of passenger comfort, cargo capacity and operating efficiency, the onboard solution is so much more practical and convenient that it would be well worth some additional expense. These technologies are all still so new that economies of scale really have not had any opportunity to come into play, and won't until enough prototyping and experimentation have permitted a variety of manufacturers and marketers to agree on some levels of acceptable standardization.
-- jurist, Nov 09 2005


Actually, this might be a great idea. Thought the added weight and volume would reduce efficiency and increase drag, the trailer could have its own regen. braking system. Or use a feed from the cars. Either way, the added mass/momentum would increase energy recovered in braking. Not really energy saved, just recovered. Now, if you have infrastructure to drop the dead and pick up a fresh battery trailer at a gas station, you have an idea. I think, however, that I have to bone this one. The thought of every Joe Idiot Schmoe pulling a trailer is like the thought of Southerners driving in snow. ARMAGEDDON!!!
-- wittyhoosier, May 10 2006


It's been done. I saw an electric Porsche of all things, like an old 944, that had a battery trailer to extend it's range.
-- J Vander, Jun 17 2007



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