Question about electricity used for Roadster owners

[shark2k]

I'm not sure if this would be better in a different section, if it is a mod can feel free to move it.

I was wondering for people whole have had the Roadster for over a year how much did your electricity usage increase? Simple question I think and am just asking out of curiousity. Thanks in advanced.

-Shark2k

[Ben W]

In the year I've had my Roadster, I've driven it about 12,000 miles. This works out to roughly 4000kWH from the plug, which at 15 cents per kWH is about $600 of electricity.

For comparison, my old car got 20MPG, so 12k miles would have used 600 gallons of premium gas. At $3/gallon, that's $1800 for gas alone, not to mention oil changes and tune-ups.

[tomsax]

Ben's numbers agree with what I've seen. To calculate your cost, multiply your miles driven by 0.336 kWh per mile (the actual number we're seeing from wall-to-wheel) then by your cost per kWh of electricity. We get a little better efficiency for our 2002 Toyota RAV4-EV, so probably other EVs will be in the same neighborhood.

Cathy and I pay the $0.0125/kWh premium for "green energy," bringing our total cost up to $0.115 per kWh hour. So our cost for 12,000 miles per year would work out to $464 for the Roadster, $442 for the RAV4-EV.

Before we got the RAV4-EV and then the Roadster about a year later, we drove most of our miles in a Honda Insight (52 mpg, $692 per 12,000 miles), most of the rest in a 1996 Nissan Pathfinder (17 mpg, $2,118 per 12,000 miles), and occasional nice-weather driving in a 1995 Acura NSX-T (21 mpg, $1,714 per 12,000 miles). The NSX and Pathfinder have moved on to new owners. We'll probably sell the Insight soon, then we'll be pure EV.

So it's not really how much does your electrical bill go up, it's how much does your total transportation energy bill go down.

[shark2k]

Originally Posted by tomsax

So it's not really how much does your electrical bill go up, it's how much does your total transportation energy bill go down.

I wasn't really asking about how much the electrical bill went up, though that is a logical direction to go. I was just curious as to how many more kWh's people were using because of the charging. I mean, whether you charge at night or day you are still going to being using the same kWh's (not really how I want to word it) as opposed to possibly getting a different price for the energy.

I was really curious only because I wanted to know how much extra electricity is being used and how much you would want to add to a solar system to compensate for that (if you could). It was really just for something down the line and also out of curiosity.

I appreciate the responses though.

-Shark2k

[Tdave]

Then Tom's number of .336 kWh per mile driven is the number you want.

[shark2k]

Originally Posted by Tdave

Then Tom's number of .336 kWh per mile driven is the number you want.

Yup. Since I started this thread any way it would be interesting to see how many miles people have driven to see how much more electricity they've used. And since I did get my answer it would be fun to see how much money they would have spent had they been driving an ICE car the same mileage vs what they spent on the extra electricity.

-Shark2k

[roblab]

[QUOTE=shark2k;38552]
I was really curious only because I wanted to know how much extra electricity is being used and how much you would want to add to a solar system to compensate for that (if you could). It was really just for something down the line and also out of curiosity.

Hey, Shark
I drove a RAV4EV for a while. I got my solar panels first, and then resized them for the new car later. I found that I use roughly 1.7kW of panels EACH for the house, the car and the well/septic pumps. So I have roughly 5 kW of panels on the roof and just about break even every year.
The RAV would use about 250 - 300 watt hours / mile, which I guess is because we didn't do 0-60 in under 4 seconds. (took about 16 actually). I would hope the Model S, driven mostly off freeway, and being more aerodynamic, could do as well or better.
Rob

[shark2k]

Thanks for the info rob. I actually got my parents to put panels on the house, but we only had enough room for a 4.725 kWh system, but by the companies estimate that installed it, it should cover about half of our electricity.

I started this thread to get some ideas for when I eventually move out and get my own place. I'm gonna keep solar in the very front of my mind and look at houses that are good for solar.

-Shark2k

[Tdave]

Originally Posted by tomsax

Ben's numbers agree with what I've seen. To calculate your cost, multiply your miles driven by 0.336 kWh per mile (the actual number we're seeing from wall-to-wheel) then by your cost per kWh of electricity. We get a little better efficiency for our 2002 Toyota RAV4-EV, so probably other EVs will be in the same neighborhood.

I'm at 0.377 kWh per mile over the first 3800 miles on my car (wall to wheel). I drive pretty aggressively, accelerate quickly whenever I can, go 70-75 mph on the highway, and probably over half my miles are highway miles. Consider my number to be close to the upper limit of real world results.