Hi Wayne - cool car!!
(Hope you don't mind I added a pic from your EV Album entry, and moved this thread over to the Fossil Fuel Free section where I think you may get some more eyeballs.)
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Originally Posted by ev99saturn
Typically EVs are anywhere from 200 to 350 wh/mi, but in my first measurement I am getting a miserable 489 wh/mi.
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Yikes! That's pretty bad.
Track it:
First off, I'd recommend starting a "fuel economy" log, because maybe -
hopefully? - that one-off measurement will turn out to be an outlier. (You can enter & track kWh units in this site's fuel log tool, btw.)
Wow - bad aero!!!
Quote:
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I have seen comments on other forums comparing the coefficient of drag of a Cobra to a 4x8 sheet of plywood or a hummer. I now see why.
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Holy cow, yes, it's unusually horrible:
Quote:
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The value of a drag coefficient, estimated by A-C, is Cd = 0.5
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(source:
http://www.automobile-catalog.com/ma..._iii/1966.html)
Use our calculator:
If you know (or can measure, estimate, or look up) the frontal area of the car, you can enter the car's particulars in our rolling & aero drag efficiency calculator, and it will give you accurate estimates of what energy consumption you can expect to see at various speeds. See:
Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com
I'll be really curious to find out what you learn from the calculator. (Also: please capture the link to your vehicle's specifics when you fill it out and post it so we can see the numbers as well - once you submit your details, the link to save or share results appears further down that page.)
The tool will also show you exactly what you need to do to reduce your consumption & increase range. Not to ruin the surprise, but as Daox already pointed out, the primary options are:
- slow down (easiest, doesn't affect looks)
- improve aero (harder, a few mods can be done without affecting looks)
- decrease rolling resistance (possibly harder, depending on LRR tire options in your tire size)
(Decreasing weight isn't really an option - it's pretty pared down already.)
Get better feedback:
The other thing I would strongly recommend: put instrumentation in the car to give you instant & "trip" feedback on your consumption. Ideally, that would show instant & resettable average Wh/mi. It would help keep you aware of YOUR contribution to consumption (driving technique).
EDIT: I see you have the Torque app in the car. Not too familiar with it, but are you getting decent feedback there?
In my car, it's more basic: an LED array that shows the voltage of each battery in the pack. Since voltage sag is a function of current draw and it's very visible on a lead acid battery, the gauge is a useful visual reminder of how much I'm demanding from the pack at any moment (and also helps me prevent battricide by keeping voltage out of the danger zone, since I don't have a fancy BMS nanny watching over my batteries).
(from:
http://forkenswift.com/electric-car-parts.htm )
cheers-
Darin