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Wednesday, January 15, 2020

Electric Cars

1914 Detroit Electric
No matter how much I hate them, they just won't go away. Iaman pointed out at lunch the other day that the savings on gasoline will be enough to make your monthly car payment. That's great, but that made me wonder how much does it cost to charge the battery in an electric car? I mean energy is energy, and the electric company doesn't take promises of rainbows in lieu of cash. So I asked Google "how much does it cost to charge an electric car" and this is the response.
The average cost of electricity in the US is 12 cents per kWh. Therefore, the average person driving the average EV 15,000 miles per year pays about $540 per year to charge it.
For a gasoline powered car that gets 20 miles per gallon, driving it 1,250 miles per month (15,000 miles a year) when gasoline costs $3 a gallon is going to cost you roughly $2,400 year, or $200 a month. So the savings on fuel ($200-$45=$155) won't make your monthly car payment ($650 for a five year loan on a $35,000 Tesla 3 or Chevy Volt), but it will make a dent.

Electric cars use about 0.3kWh per mile, or about 4 cents a mile, so you are going to save some money on fuel, but you still have all your other expenses like insurance, tires and depreciation. Maintenance is an unknown. The battery will last for years, but it will be expensive to replace, about the same as replacing the engine in a gasoline powered vehicle.

The linked article makes a pretty good economic case for buying an electric car, which brings us the last objection I can come up with - charging. It takes time, and charging stations are few and far between, other than your house. So now I'm wondering could you carry one of those little portable Honda generators in your trunk to charge your car in an emergency? Well, sort of:
For a recent video on the BMW plug-in car, GadgetReview rented a generator at Home Depot, attached the i3's charge cord, and left to see if this improvised method could recover any range. Sure enough, after a half hour of charging in a parking lot, the i3 had gained four miles of range. - Green Car Reports
A half hour to gain 4 miles? Okay then, that's not really worth the effort or expense. How much current is flowing in a typical home charging setup? 30 Amps on a 220 Volt circuit seems to be the number, which is like the power needed by an electric oven or an electric water heater. Multiply those two numbers and you get 6.6 kilowatts, so to get the 30 kilowatt-hours we need to drive 100 miles, the car will need to be plugged in for 4 to 5 hours.

Since the economics point towards electric cars, I thought I would check on how much a used one would cost. I bought a couple of new cars 20 years ago, but I'm not doing that anymore. Prices on used Tesla Model 3's seem be higher than the list price. Could this be an inverse symptom of the Trump Derangement Syndrome?

When I was looking for a picture, none of the electric cars really stood out. I guess that should be expected since they are reducing the car to an appliance, and it's hard for me to get excited about appliance styling.



4 comments:

xoxoxoBruce said...

I was wondering how big a generator you'd need not to recharge a dead battery but supply enough juice to keep the car moving then plug in to charge it when you got home? The electronic control system may not allow that though.

Chuck Pergiel said...

30kWh will get you 100 miles. At 30 MPH, 100 miles will take you 3 hours. 30kWh divided by 3 hours gives you 10kW, which is a pretty hefty generator, like a Duromax XP13000EH, $1400 from Amazon.

xoxoxoBruce said...

That's where I get messed up, 30kWh to go 100 miles. 30kWh = 30,000 watts per hour, so I'm thinking to get 100 miles I'd have to cover that 100 miles in an hour.

But you say that 30,000 watts cat be spread out over several hours. Thank you.

Chuck Pergiel said...

I'm glad my explanation made sense. That's not always the case.