The Zing! (Custom-built prototype hybrid tadpole trike)

[sendler]

Originally Posted by Ecky

Ken, what do you feel is the smallest battery size one could use in a vehicle like yours and still have a good driving experience? 10 mile range? 5? What is the minimum cost in battery capacity to make this concept work, and what are the disadvantages of using smaller capacities other than the obvious?

Initial cost seems to me the largest single barrier to entry in electric vehicles, but one could still take advantage of a more efficient drivetrain like the one you use in the Zing, only with a much smaller battery pack. The generator would start much sooner, but you'd still have a highly efficient and fun vehicle to drive.

Keep in mind that batteries have max discharge current rates so you can only go so small if you want an occasional 40hp to climb a hill.

[pete c]

Originally Posted by Frank Lee

The masses aren't known for their brilliance.

amen, brother!

[pete c]

One more suggestion, Ken.

One of the beauties of a pure series hybrid is that it can function as a straight EV.

That being the case, I have thought why not make the ICE/generator portable so it can sit in the garage when not needed.

I understand that it might be too heavy to simply be hoisted out of the trunk. If that is the case, maybe it could be mounted with a hatch above it so you could back into the garage, open the hatch, hook it to a chain fall and hoist away.

[Mr. Previa]

Gotta say that is the coolest trike I have ever seen!

[NeilBlanchard]

I think The Zing! will show how efficient a serial hybrid can be. You have to consider the *average* efficiency of a drivetrain, and a mechanical can be at peak efficiency part of the time. A serial hybrid can have a smaller displacement engine because it only has to meet the average power output.

The FVT eVaro gets 300-350 miles of range from less than 2.5 gallons of gasoline, using a customized 1100cc Goldwing engine spinning a 20kW generator. It can charge the 21kWh lithium pack in about 1 hour, which then lets you drive ~125 miles on the electric drivetrain. The genset then starts again and runs for about 1 hour, and then you can drive for another ~125 miles.

The eVaro has a total range of 400-450 miles with a plugin charge (21kWh total capacity) and ~2.5 gallons of gasoline. It gets *all* of it active braking power from regenerative braking and it has free wheel coasting when you lift your right foot off the accelerator pedal. It accelerates 0-60mph in less than 5 seconds, and stops 60-0mph in about 130 feet.

The eVaro and the Zing! are very similar in many ways: 3 wheels in a reverse trike layout, 2 people sitting in tandem, electric front wheel drive, serial hybrid. The biggest differences are weight (eVaro is about 2100-2200 pounds I think?) and it is larger overall, too. Aero Cd is a close call, but the Zing! very likely has less frontal area.

[pete c]

Read about the Zing on the aptera site.

Good info. I recommend it to anyone interested in the Zing.

One thing there that I hadn't seen here was the generator weight (49lbs). And it costs around a grand?

To be honest, it had my BS detector going off rather loudly.

I'm far from a generator authority, but, have looked into them for my RV and I don't see anything with that power output under 100 lbs. I realize that these have frames and tanks, but, they don't appear to weigh more than a few pounds.

Having read a fair bit from you, Ken, you don't strike me as a BSer, so I will ignore that confounded detector to the best of my ability.

I would love to see more info on this generator, assuming it's not of the" I could tell you, but I'd have to kill you" trade secret kinda stuff.

[Ken Fry]

Originally Posted by pete c

One more suggestion, Ken.

One of the beauties of a pure series hybrid is that it can function as a straight EV.

That being the case, I have thought why not make the ICE/generator portable so it can sit in the garage when not needed.

I understand that it might be too heavy to simply be hoisted out of the trunk. If that is the case, maybe it could be mounted with a hatch above it so you could back into the garage, open the hatch, hook it to a chain fall and hoist away.

Yet another good suggestion. I've been thinking along those lines, and may do something similar in the 3rd or 4th one I build. I've had this poorly formulated idea of a roll-out unit with drop-down wheels, or maybe an accessory cart sized so the unit can be slid out and onto the cart.

Thanks, Ken

[Ken Fry]

Originally Posted by pete c

I would love to see more info on this generator, assuming it's not of the" I could tell you, but I'd have to kill you" trade secret kinda stuff.

The POC info is does not apply to the production version, but is illustrative... so no, I won't have to kill you. I hope I made it clear over at the Aptera site that the 49 lb applies to the unit in the POC. The production one is unfortunately twice as heavy despite being only 30% more powerful.

In the POC, the electric machine is an Etek permanent magnet motor, which weighs 22 lbs. To get the desired output voltage matched with the engine's peak efficiency point (which occurs at 2800 rpm) requires a step up drive. I don't have the spreadsheet in front of me, and am not sure if I put the belt and pulleys in with the 49 lbs. As I type that number, I'm thinking that it can't be right. I think, (although now I am having doubts) the engine ended up at 32 lb after removing it's fuel tank, muffler, recoil starter, and some miscellaneous pieces. So 22 + 32 is 54, and I probably added 5 lb for the belt drive to get 59. The engine (250 cc B&S) ships at 40 lb, and I doubt the the packaging, starter, tank, muffler and a couple bits come to 13 lbs (to make an engine weight of 27 lb.)

So I think your BS detectors are working correctly: It is probably 59, not 49. (On the other hand, it doesn't feel as heavy as a 50 lb bag of sand -- getting it in and out of the subframe requires lifting at odd angles, and I'm a weakling, etc.) Next time I have it out of the car, I have to weigh it.

The efficiency curve of the Eteks (which are no longer available) looks like that of the PMG 132, but the ones I have are about 1% lower at peak: 89%. This is an actual curve from the dyno test of the motor itself (each Etek shipped with it's own dyno curve from QC test runs) whereas the published curves for the Perm are likely to be averages from dyno tests. The Eteks were often advertised as being over 90% efficient -- perhaps some were. Mine may be lower than average.

In the POC, the generator operation is manual. I do all sorts of thing "wrong" in testing the POC, but in anything like the operation of the real deal (in which the driver determines when to start the generator, but the microprocessor determines when to shut it off) the load on the generator is constant, and the engine runs at full throttle. The ammeter is always at 50-60 amps. There comes a point in the charge cycle when the amperage drops. At that point, it no longer makes sense to run the engine, because load is falling off. In the POC, the batteries are 60 AH and can accept a 3C charge -- an amount the engine cannot produce. So regen continues to function with the generator running, albeit not quite as well as with the engine off. In ordinary driving the friction brakes are never used, but only if you are a bit more conscious with the engine running.

In the production version, the generator will be PMAC (brushless) rather than brushed. The better versions of these are typically 93-94% efficient over a reasonably broad range. Specs for the Perm PGS 150, for example are here:
Permanently Excited Synchronous Generators - Perm Motor GmbH

[Ken Fry]

Originally Posted by JackMcCornack

On another forum, Ken mentioned...Because it's cheaper (and in some situations, greener) to get your recharge power from a wall plug than from a gas station.

If I were building a plug-in hybrid, I'd do it your way, Ken, because on the small vehicle scale, simplicity trumps efficiency. But if there were an easy way to do it (perhaps some lightweight and inexpensive electronic way?) your customers will be money ahead if they series-hybrid their way home from a long drive and arrive with the battery at a low charge level. Then they can recharge it back to a high level on coal instead of gasoline.

All correct, and I think that is the logic/marketing mix behind the Volt.

In what I think of as a "pure" series hybrid, you need to stay a little ways away from really low battery levels, because you may have a mile long hill or three mile hill on the way home. The engine alone is inadequate to propel you up a long hill if you start with low charge: you'll make it up, but not at the usual performance levels.

I think your electronics idea would work. It would be possible to integrate GPS with the charge controller, and as long as you programmed your trip, you could arrive with the lowest possible charge.

I may have already mentioned this (in this thread or elsewhere). The night before an electric car event in downtown Atlanta, I had 30% charge (good for about 12 miles or so). Not enough to get down and back. (But I can get down and back with a full charge.) All seemed well until I heard a little pop. The fuse between charger and batteries had blown, I did not have a replacement, and stores were closed. So the next morning, I started the engine, left with 30% charge and arrived downtown with 50%. That allowed me to drive all the way back in silence. In the same admittedly arbitrary and coincidental situation, a Volt would have done the whole trip with the engine cycling.

The Volt is a pretty neat car. I just prefer manual control and simple architecture.

[Ken Fry]

Originally Posted by Mr. Previa

Gotta say that is the coolest trike I have ever seen!

Thanks!