How far can I go?

"What do you mean, you "don't know how far it goes""? - co-worker

Well I don't... At least not yet.

Something fairly essential was missing when I bought the Comuta Van: A fuel gauge.
I knew this of course but a voltmeter shouldn't be a hard thing to come by. Being a 25 year old prototype, the odds of finding an exact replacement are slim. Not to fear, I've read that Curtis instruments sells this sort of thing. They are the same company that made the super-wham-o-dyne motor controller that I'm using.

They make a nice, simple, color-coded LED bar graph gauge that is green when full, and drops into blinking red when empty. Kind of pricey though. Some people on the newsgroups are trying to sell me on these "E-meters" that track amp-by-amp discharge to give you the exact moment that you're going to cease moving. Even more pricey. Where does anyone get anything these days? E-bay of course. Wow...none to be had. The EV trading post at http://www.austinev.org/evtradinpost/has one for half price so I buy it and hope for the best. We're doing the snail-mail dance with money orders and shipping so it'll be a while.

In the meantime, I'm bravely driving around with a 2" hole in my dash and no idea how far I'm going to go. The weather is between 45-70 degrees so the cold weather shouldn't affect the batteries too much yet. Over the days I start running errands to the grocery store, putting around on the backroads and hitting my favorite coffee shop. I'm logging the odometer with longer and longer drives to see how far I can go. I'm taking my time learning how it drives and trying to adapt my driving habits to a new style of vehicle.

Here's a neat thing I discovered that almost led me to wreck the thing on my 2nd trip out:

When you "coast" in a gasoline car, engine compression and friction slow you down pretty quick. You don't pay any attention to it. It just is, and you know how far you're going to coast before you roll to a stop at the traffic light. In an EV, there is no friction, and certainly no compression. The only friction is the tires on the pavement. Even with the motor in gear, it's like coasting in neutral. You roll a lot further. I learned the hard way by not allotting enough braking room and nearly rear-ending the car in front of me. In reality this is good though, because you learn to conserve energy by coasting down every little hill you find because it's much easier to maintain speed. By the "burp 'n coast" method, you learn to extend your range. You learn to plot your routes so that you depart by coasting down steep hills, and travel the flats and shallow grades coming home (or vice/versa).

One day, I'd run a string of errands around town that led me to put 32 miles on in stop 'n go traffic, up and down an assortment of hills. I figured I didn't have much battery left, but I wanted to know just how far I could push it. I found a scenic circular drive in a residential area nearby and drove a few long laps. Finally around 38 miles I sensed a lack of performance, so I headed home. By the time I was 1/16th of a mile from home, things really started slowing down. By the time I hit my parking spot, I hit 40.7 miles on the clock and I was out of juice. That's roughly 40 miles of hills and stop 'n go traffic. In a perfect world, I could probably eke out 45-50 miles.

It took about 6 hours to charge up and for 3.5 hours of that, the charger buzzed and hummed so loud I thought it would vibrate itself right off of the workbench. Thank God it's in the basement where I can isolate the sound.