This was going to be a brief addendum to my somewhat cryptic “Do the math” remark that I made the other day. But then I realized that the remarks were more of a simplistic, “See also…” and a few trivial clarifiers on questions I’d received.
It’s become more of a diatribe.
Because a few people started countering with a slew of, “Yeah, but…” and “Have you thought about…”
A couple of things to keep in mind:
- I didn’t assemble that particular form.
- Don’t read into it or assume things.
- And I hear you yelling, “But need my leased car to get 1500 miles per day and I expect it to get 600 miles between refueling and only need 26.3 seconds to refuel!” — No, you don’t. Nor does your own bladder. Because physics. And physiology. You cannot sit in a single seat, unmoving, for more than two or three hours.
- “But it’s not in kilometers!” or “I need to have Canadian dollars (or AUD or LKR), you Amero-centric A-hole!” Fine, then think of it as being unit-less. Just envision that it uses your own symbol — the math is exactly the same.
- For the questions themselves, I’ll see if I can simplify them — you know, by not reading into them:
- Miles driven per month
On average. In the average month, how far will you drive? My father has a 1998 Sebring with 175,000 miles on the odometer. That works out to about 700 miles per month.
- Average Wh/mi consumption
This one’s a bit less clear, but it refers to a given EV. They’re often about 280 Wh/mile, but it also links to some general guidelines so you can pick/choose. The Jag and Audi will get insanely-inefficient ratings.
- Electricity cost per kWh
In Washington, it’s typical to see energy at an insanely low 5¢/kWh (we actually pay 4.98 cents per kWh, but who’s counting?). Other areas around NA might be as high as 20 or 25¢ per kWh. Use the dollar value in. Not cents.
- Fuel Efficiency MPG
Do the math and calculate how much fuel your car actually uses. Do not rely solely on its onboard computer. Do the math to see how your fuel consumption varies over time. To calculate your mileage, when you fill the tank, write down the Starting odometer reading. Fill the tank (don’t top it off or wait until the temperature is “perfect”, just fill it), then just drive it like you normally do. Next, write down your Ending mileage when you next fill the tank. Subtract Starting from Ending. That’s how far you’ve driven — the M part of MPG. Now divide that by the number of Gallons you just added to the tank. That’s the G part. Or:
MPG = ( Ending – Starting ) / Gallons
- Fuel cost per gallon
Obviously, this will vary. But we’re only looking for the average fuel cost over time. Not day by day, nor hour by hour — and certainly not by trying to save four cents per gallon by driving 43 miles across a metro area. Just the general fuel price in your area.
So, what are the results for our examples?
And it doesn’t touch on oil changes. But that’s another rant.