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Some call its styling cartoonish, but for this Sparrow pilot, his three-wheeled EV gets the job done without fuss or muss using standard components and a bold concept.

The First Thousand Miles

The Corbin Sparrow, an Owner's Perspective

By Keith Bierman

It's often claimed that unless (and until) some new battery breakthrough is acheived, that electric vehicles are a pipe dream. Well, I drive a 'pipe dream' very day. It's called the Corbin Sparrow. It uses no special or exotic technology, and is wonderful demonstration that usable electric vehicles can be produced and sold with today's technologies.

The Corbin Sparrow is a single person electric vehicle. I've been using it as my primary commute vehicle for a few weeks, and it's worked well. I am getting rid of our old RX-7. I am keeping my motorcycle, but that is more for the joy of riding than for the extra range it affords. Thus the Sparrow has completely displaced one car, and several commute trips per week on the motorcycle.

On the downside, government incentives all miss the target, but more on that later.

I have a 50 mile commute (25m each way), mostly freeway (so speeds ranging from nearly 0 stop and go, up to something well over the posted speed limit. On a typical day, I arrive at work with aproximately a 50% charge. I seldom leave for home with less than a 90% charge (having recharged at work, run to another work campus, or other errands). Most frequently I leave with a 100% charge, having fully recharged at work. As the Sparrow only requires a 110v, 15amp (or less in actual use) outlet, special recharging stations are not required. At the building where my office is housed, there are outlets on the side of the building. I often have meetings at Sun's Willow Road campus, where there is a special EV "fueling" station (for the GM EV1) and standard outlets. In additional there are outlets on the sides of many of the buildings in the complex.

While acceleration from a standing stop is a bit poor in the Sparrow, top speed I've attained is about 80mph, which is adequate for my needs. The range is ample for my commuting needs.

The vehicle itself has been called "cartoonish" in terms of styling. But, beauty is always in the eyes of the beholder. Basically, here's what the Sparrow offers:

Unlike the major manufacters who have been deploying a small number of prohibitively expensive and complex vehicles, largely to prove that the technology isn't ready for Prime Time, Corbin has been ramping up production and intends to make a profit. So, the Sparrow relies on off the shelf parts, and fiberglass that they can craft themselves. The result is not as well polished as, say, a high end European luxury car, nor even a typical american domestic car. However, the various flaws in fit in finish don't do anything to detract from the sucessful proof of concept.

Corbin continues to crank out the current model, which one might veiw as a production beta. They are hard at work on a next generation model, which is intended to address a lot of the fit and finish issues (for starters, the fiberglass is replaced with a carbon fiber composite which is lighter, stronger, tighter tolerances, and can be mass produced).

Early Sparrow shipments had difficulties with the "controller". Corbin has essentially recalled them all, and is replacing them with one of two updated units. Corbin is moving towards Kilovac as a supplier, and most Sparrows seem to be scheduled for retrofitting with them. Curtis, the old supplier, has an updated unit which seems to work very well. I have one of the latter, and am quite pleased.

Contemporary Sparrows still have some issues with squeling brakes, water leaks, and other minor annoyances. Those interested in the day to day griping of Sparrow owners may wish to check out groups.yahoo.com/SFBA_sparrow and sparrow_ev (the former is for bay area sparrow owners, the latter for all sparrow owners). As of this writing (Feb 2001) many Sparrow owners are awaiting the return of their electric feathered friends, from the controller refitting operation.

Technical notes:

An electric vehicle, like any other, has frame, suspension, brakes, lights, etc. These are not particularly different for an EV; but may be lighter where feasible

In addition, an EV has an electric motor, batteries, and a controller. Many EV's have no transmission as such, or a very simplified one.

The Sparrow has 13 optima "yellow top" batteries, a classic DC brush motor, a big kevlar drive belt, and a controller. Oil changes and the like, of course, are not needed. Every couple of years (2-5) the batteries and the brushes will need to be replaced. Lead Acid batteries are highly recyclable, and are typically recycled, so the load on the environment is minimal.

There is, of course, no gas gauge. Instead, Corbin provides two meters:

1) An amp meter
2) An "E" meter

The amp meter shows instantenous current draw from the battery pack. Thus one can see the consequence of too heavy a foot on the accelerator ;> Note that the faster one discharges a lead acid battery, the lower the effecitive capacity of the battery. So, traveling at 80mph (consuming 150amps) is likely to result ina shorter range than traveling at 55mph at closer to 50amps.

The "E" meter shows pack voltage, amps, amphours (or KwH), and a computed %effective charge available. The %charge is easiest to read, but least reliable.

A key challenge for any lead acid based EV (and perhaps any EV) is keeping all the batteries at a consistent level of performance. Corbin has not deployed any special technology in this area, but if one is careful to not overly discharge the batteries, keep them charged, and not let them sit is a good start. Allowing the charger to get to 100% is important to battery health. There is a product which some Sparrow owners are installing which should result in longer pack life. http://powerdesigners.com/ for details.

Spec Overview:

156v nominal system (voltage peaks at 215v or so, at top of charging/equalization phase). 1350lbs curbweight.

The motor is an Advanced DC Motors, continuous "E" Rating 25 hp (20 kW) continuous, 40 hp peak, Curtis or Kilovac Controller.

Charger is a Zivan NG3, 120 or 220v (not field switchable).

Batteries are 13 Optima spiral cell technology D900M series batteries, weight of each battery: 46 lbs. yeilding a total battery weight: 598 lbs. 60 amp hour at C20 (constant amp discharge over a 20-hour period) 45 amp hour at C1 (constant amp discharge over a one-hour period). No doubt that the factory is always evaluating alternative battery suppliers with equivalent or better performance.

Bottom line:

I enjoy driving my Sparrow, and it's proving to be a very nice commuting vehicle. It is still a bit more appropriate to someone able to deal with early adopter issues (a Sparrow Dealer isn't likely to be able to provide the level of support that, say, a SAAB dealer can). Owners may have to use a wrench to tigthen things up, and an ability to use simple circuit debugging may be handy). None of this is fundamental to the technology, but to the youth of Corbin as a manufacter of vehicles.

Government Issues:

In an ideal universe, vehicle costs would include not only the direct costs to the owner/user, but would include factors such as:

1) Time to destination
2) Wear and tear on the roads
3) Congestion contribution
4) Air pollution caused

There are a variety of incentives that government (federal and state) have provided to encourage the use of electric vehicles. However, they have completely missed the mark.

There is a Federal Tax Credit, but according to many experts, it only applies to *automobiles*. The Sparrow is classified by the DOT as a motorcycle.

There are also Califonia State initiatives such as:

A) AB 2061 which provides $ to drivers who purchase a qualifying electric vehicle. Alas, it too leaves out the California designed and bulit Sparrow.

B) AB 71 which was designed to permit EV's in carpool lanes (thus providing drivers with a powerful incentive, the gift of time). However, it too is being interpreted by CARB as not including Sparrows, again because they are a motorcycle.

One might have thought that AB71 applying to Sparrows would be irrelvant because they *are* motorcycles. But the State, in it's infinite wisdom also put into the vehicle code section 21714, which proscribes the driver of an enclosed three wheeled motorcycle from driving in the HOV lane (note that the only production three wheeled motorcycle generally available in the state is the Coribin Sparrow).

Since the majority of commuters travel alone, and travel less than 40miles each way in their daily commutes, one would have thought that if the government were to provide any incentives, they would focus them on vehicles such as the Sparrow which provide no direct pollution (and due to their high energy efficiency place a minimal indirect load), consume less space (minimizing congestion, and parking issues) and due to their relatively light weight low wear and tear on the roads themselves).

The State of Georgia is ahead in this area, their equivalent of AB 2061 applies to Sparrows.

My Analysis:

What Corbin did right:

  1. Starting with a clean slate, permitted a good technical solution to the problem of moving a person, with minimal impact.
  2. Using standard electrical connections minimizes the need for special infrastructure, making the vehicle easy to adopt.
  3. Using off the shelf technology minimized start up costs.

What Corbin did wrong:

  1. An inappropritate choice of controller (the Curtis controllers were rated for 144v, not 156. Testing showed no problems, but over time at least one component supplier no longer provided components which worked well beyond spec with unfortunate results). Either the pack should have been adjusted downward to 144v or the controller should have been selected for 156v as the nominal design point.
  2. Variety of minor mechanical design issues.
  3. A serious documentation effort; as it stands one can't go to an independent repair depot, without having to (or having them) essentially reverse engineer the specifications. As best I can tell, the factory doesn't have much in the way of formal documents (they aren't supressing information, they haven't written it).
  4. They aggressively signed up dealers around the country. No dealer can get enough cars to be profitable just selling Corbins. I chatted with two local dealers, one who urged me to buy a different vehicle! The other was quick to promise things which he had no way on earth to deliever. Direct sales, and documentation to enable independent support would have served them better.
But then that's only my not so humble opinion.

Times Article Viewed: 10898
Published: 31-Mar-2001

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