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So how do you think normal driving for truck looks like ? In europe it is highway driving at constant speed, more or less constant load for hundreds miles.

To avoid each person having a different metric, we use standardized drivecycles. The drivecycle that the EU uses to model how people typically drive for vehicle mpg ratings is called the NEDC -- the New European Drive Cycle. It is a combination of urban and highway driving that approximates typical european driving patterns (which, by the way, are lower energy than typical US driving patterns -- hence the US uses FTP75 (city) and US06 (hwy), which are higher energy, and correspondingly leads to lower MPG figures for the same car in the US). You can see the NEDC here.

If you want to talk about pure highway driving, even that is not constant speed. Speed on the highway varies based on traffic density, random factors (passing, being passed, etc), current weather conditions, stops (gas, rest, etc), start and end accel/decel, exits (to surface streets or other highways), and driver randomness. Beyond speed, energy consumption varies based on weather and especially altitude changes. For an example, here are actual measurements taken from a vehicle in the US. Here's a test drive that starts with city and progresses to intra-urban freeway. Your mileage may vary.

(I have my own drive data recordings, but I am not at liberty to disclose them, so I'm linking to publicly available ones)

Highway driving runs an engine much more efficiently than city driving. You're closer to the peak efficiency (although not at it), you brake less, idling is basically eliminated, etc. Now, there's obviously a big downside -- your aero drag is *way* higher, and your rolling drag slightly higher (yes). In non-hybrid vehicles, the upsides outweigh the downsides (sometimes significantly). In hybrid vehicles, the downsides usually outweigh the upsides.

No this is not from wiki. It is from book called "Automobile fuels" (translated)

Right. Which is why I said, "If you had cited ... you would have..." instead of "You cited... you did." Understand? I'm pointing out that different sources give different numbers because there is no single correct number because they're not a single chemical mixture. You've picked one source to latch onto, when there *is no single answer*. Check other sources; you'll see what I mean. Mixtures vary from location to location and even day to day (for example, summer versus winter blends). They even change from year to year, as standards and refineries are always changing. Their energy densities vary, too. But overall, the *current global average* is about 15% denser for diesel than gasoline.

I don't know how many times I need to stress this, but let me do so once more: There Is No Single Fuel Called Gasoline Or A Single Fuel Called Diesel. How about this -- how about I cite a bunch of random sources?

Simetric: 820-950kg/m^3
Alan Harvey, National Institutes of Standards and Technology: 850kg/m^3 typical, but 825-890.
Engineering Toolbox: 810-960kg/m^3
MSDS: 810-880kg/m^3

Gasoline:
MSDS: 710-770 kg/m^3
Simetric: 737kg/m^3
Engineering Toolbox: 680-740kg/m^3

No it's not. Well, yes to the Volt, but the others are non-plug-in parallel hybrids, whereas the Volt is a plug-in series hybrid and the Metric Mind AC Honda (which I believe is the one the GPP mentioned) is a pure plug-in electric with optional range extender trailer. A fuel range-extender for long trips means that the car's electric-only range isn't an issue, while being able to charge from the grid means that in practice, very little fuel is actually consumed.

And the fact that you can build the equivalent of those big-company factory cars in your garage and achieve fairly similar performance and practicality says a lot about how hard building one of these cars is NOT.

More efficient is a possability, but I suspect that once you throw in the differential and CV joints you'll lose the weight and cost advantages.

True, but you're not going to loose that much power in a differential, and you might want to have CV joints anyways to keep the weight of the motors as sprung rather than unsprung weight.

A quick search says that a differential will be 94-97% efficient. From looking at different efficiency graphs, such as on this site, you can have percentage differences of greater than 5% between different electric motors, within their optimal power zones.

Personally, it sounds like something for a design team to look at. Don't forget that you'll most likely be looking at hub motors if you're going for direct wheel drive, they're less efficient than a similar power traditional motor with a shaft.

You might be able to figure all this out with a proper design team and simulations, but I wouldn't be surprised at all if they ended up building prototypes to test it out.

The acceleration is could be a big deal. That's based on the flat power curve of an electric motor and it's ability to operate from a standstill. While a gasoline engine is still slipping the clutch (or torque converter) to avoid stalling, the electric is applying 100% torque. The acceleration will probably be a selling feature in the U.S. There's a lot of misperception that electric cars will feel like driving a golf cart.

Agreed. Especially given that electric motors tend to be more efficient the larger they are, under powering the motor doesn't make much sense.

I can well imagine dealers having a demo car with the traction control shut off so they can demonstrate that the car can burn rubber. Because a lot of people don't realise that burning rubber means lost acceleration, there will probably be an aftermarket (legit or gray) for the firmware that lets you do that.

I don't doubt that, though I think that most people willing to change out their car's chips to 'increase performance' will quickly figure out that burning rubber is counterproductive for both fuel economy and acceleration rates. I wouldn't underestimate the knowledge of the average nascar loving hot-rodder. Not that they wouldn't think that spinning tires is cool, but that they'd know that it's not the best way towards acceleration and plan accordingly. Maybe with a switch turning traction control on or off.

On the other hand, go two motors down to the SIEMENS 1LH5118, and you have a 19.7HP continous rated motor that has 90.8 max ft-pounds of torque. Good job finding a site with more detailed specifications on electric motors, most sites only have the continous ratings. I especially like the power curves.

One thing this thread has done is get me to research electric motors a bit more, the number of types they have is staggering. Of course, when you think about it, the average car has at least two electric motors, likely more, and only one IC engine.

Then you figure all the electric tools, compressors, AC/Heating systems, washing machines, computer fans, etc... I wouldn't consider it outragous to find out that there's at least an order of magnitude more electric motors than IC ones. Of course, most of them are very small in comparison to a car engine.

There's dozens of different types, depending on whether it's going to be fed AC or DC, is intended for a constant torque or constant speed despite load, or variable. Whether it's going to be starting/stopping a lot, or hardly ever. Whether it can have a gradual start, or a sprint start.

Looking at the power curves, the electric motor has nearly 100% of it's torque available at a mere 400 rpm, while they don't even list torque for the gasoline engine until 1800 RPM. It ends at 3600 RPM. Meanwhile you find motors rated between 3500 and 10000 RPM. Combined with the low speed torque, an appropriate reduction gear might be able to eliminate the need for shifting. Going by the graphs(150-125), for efficiency sake you'd simply want 25mph correspond to ~2800 rpm. Then 75 mph would be ~8400 RPM, which is within standards. Well, for the MES 200-250, I'd peg 25mph at 2000 rpm, giving 75mph at 6000 rpm. You'd have plenty of overhead still with those motors. Efficiency above 90% for much of it.

Show me a reference that says that a gasoline engine of a given HP rating produces greater torque than an electric motor of the same HP rating.

Especially across the range that an electric motor is capable of exerting that torque.

I have been watching the EV conversion market for a long time. I have amassed a few quality web sites links for advise on converting a car to EV and some of them sell the parts. The arguments about moving the pollution from tail pipe to smoke stack are just arguments. As long as you don t expect an EV to totally replace an ICE car and want to save energy and money on your daily commute, an EV is great way to go.

Most EVers have one EV car for the daily drive and one ICE or hybrid for longer trips. All of the EVers I have read about get a kick out of sneeking up on friends with their silent cars and out running sports cars from a standing start at the light. Electric motors can provide max torq at any RPM. ICE motors only supply max torq at a very narrow range of RPMs.

The only reason I don t build one myself is the lack cash to buy a host car and materials to convert it. If I had the cash, I would go with an AC based system with nickel metal hydride batteries and maybe some ultra-caps for enhanced acceleration and regenerative braking. AC systems do the best job at regenerative breaking even without ultra-caps. DC systems require special circuits and the motors requre an extra set of brushes for regenerative breaking or reverse.

The sites listed here have complete guides and step-by-step pictures of their examples conversions. The hardest part is understanding how to size the motor you need and the battery pack to run it and where/how to mount the pack. Otherwise anybody that can change a waterpump or alternator can do one of these. It just takes longer and lots of planning.
AC drive systems for electric vehicles
Electro Automotive Catalog
Electro Automotive Electric Car Conversions
High End AC Drive Systems and Power Electronics for Electric Vehicles
AC Propulsion Home
EVA-DC - Build an EV Choosing a Car

I have been watching the EV conversion market for a long time. I have amassed a few quality web sites links for advise on converting a car to EV and some of them sell the parts. The arguments about moving the pollution from tail pipe to smoke stack are just arguments. As long as you don t expect an EV to totally replace an ICE car and want to save energy and money on your daily commute, an EV is great way to go.

Most EVers have one EV car for the daily drive and one ICE or hybrid for longer trips. All of the EVers I have read about get a kick out of sneeking up on friends with their silent cars and out running sports cars from a standing start at the light. Electric motors can provide max torq at any RPM. ICE motors only supply max torq at a very narrow range of RPMs.

The only reason I don t build one myself is the lack cash to buy a host car and materials to convert it. If I had the cash, I would go with an AC based system with nickel metal hydride batteries and maybe some ultra-caps for enhanced acceleration and regenerative braking. AC systems do the best job at regenerative breaking even without ultra-caps. DC systems require special circuits and the motors requre an extra set of brushes for regenerative breaking or reverse.

The sites listed here have complete guides and step-by-step pictures of their examples conversions. The hardest part is understanding how to size the motor you need and the battery pack to run it and where/how to mount the pack. Otherwise anybody that can change a waterpump or alternator can do one of these. It just takes longer and lots of planning.
AC drive systems for electric vehicles
Electro Automotive Catalog
Electro Automotive Electric Car Conversions
High End AC Drive Systems and Power Electronics for Electric Vehicles
AC Propulsion Home
EVA-DC - Build an EV Choosing a Car

And even in this kind of hybrid regenerative braking can result in a net loss of fuel economy if you are primarily driving it at constant speed on the highway, because you don't do much braking in the first place.

Now, I'm not overly familiar with the Prius' electric motor system, but I do know that AC-electric drive motors have regeneration built in by nature of their design. While a DC electric car has to have a separate generator to recharge their batteries, AC cars such as the EV1, ACPropulsion's system, and Siemen's systems (as sold by Metric Mind) all have regen without any extra hardware.

I heard from someone who had an EV1 at an EV club meeting. They took it on a 200+ mile round trip. Going uphill they had to stop & charge at ~60miles, but coming home they got a free ride down the hill...

Does someone want to donate a direct-conversion methanol fuel cell to the project?

If you're interested in throwing a lot of money (yours or someone else's) into the project, you're better off going with an advanced battery chemistry, like lithium ion or nimh. The fuel cell battery charger you pointed to delivers 50 watts. This would not be acceptable for moving a bike down the road, for the same reason that fuel cells are not [yet] acceptable for moving cars -- they require too much mass to generate enough power. At 6kg (without fuel) this fuel cell has a specific power of a little over 4 w/kg. Lithium ion can give over 350-400 w/kg, especially if packaged in large cells. And though specific energy is very high, lithium ion is actually considered fairly crappy in terms of power output, compared with other battery chemistries.

MetricMind's lithium ion batteries are sized for a car, but their specs are useful as an example:

http://metricmind.com/battery.htm

And unless it runs on pure hydrogen, it emits exhaust. It's a little cleaner than a combustion engine, it's quiet, and a little more efficient (compared to burning the methanol and generating the electricity conventionally), but right now, batteries are just a better solution.

I've recently had a chance to try out the WaveCrest TidalForce bike, powered by NiMH batteries. At 750W (approx 1HP), it's a pretty fun ride:

http://tidalforce.com/