MINI E lessons learned

[planet4ever]

...Postscript: I guess that means I have already produced enough electricity to drive my Leaf about 300,000 miles!

I'l pay you 15 cents per kWh... have some extra wire lying around here somewhere....hmm...

Just a minute, while I do the math. Got it: $0.15/kWh * 20,000kWh/year = $3000/year.

I sure hope you find that wire! Depending on where you live in Cupertino, it's only about twenty five miles as the crow flies from my house to yours. 'Course, it might be more efficient to put solar panels on your own roof. ... Just a thought.

 

[DeaneG]

Course, it might be more efficient to put solar panels on your own roof. ... Just a thought.

I agree but payback = 7 years and probably moving = 3 years.

I am using a guess of 2.5 miles per AC kWh (wall to wheel efficiency, heavy car, lead foot). Everyone else seems to be calculating based on battery to wheel numbers. But the power comes from the wall, not the battery.

Tesla roadster wall-to-wheel numbers are in the 300 to 400 Wh/mile range (3.3 to 2.5 mile/kWh).

 

[planet4ever]

Course, it might be more efficient to put solar panels on your own roof. ... Just a thought.

I agree but payback = 7 years and probably moving = 3 years.

I remember, now, you said that once before in a different thread. To which I think I responded that you can sell the house for more if it has solar panels.

[Can you guess? I'm a bit of a solar nut.]

I am using a guess of 2.5 miles per AC kWh (wall to wheel efficiency, heavy car, lead foot).

I used to have a lead foot, too, until I drove a Prius. It really does encourage you to drive more economically, and I think the Leaf will do the same.

Everyone else seems to be calculating based on battery to wheel numbers. But the power comes from the wall, not the battery.

Tesla roadster wall-to-wheel numbers are in the 300 to 400 Wh/mile range (3.3 to 2.5 mile/kWh).

I agree that wall-to-wheel is the right way to think about it, but I don't think the Tesla's numbers are comparable. Tesla is an out-and-out sports car, driven by rich sports car drivers. And their batteries are basically off-the-shelf laptop computer batteries.

Look at it this way: Nissan claims 70 to 130 miles on a 24kWh battery. (OK, less in some extreme situations, like stuck in a traffic jam for 8 hours with the AC on full.) Wall to battery efficiency is probably going to be between 85% and 90%, so 27-28kWh max from the wall to charge fully if 24kWh is usable - many people believe that is 10%-20% high. Your 2.5 miles/kWh looks like an absolutely worst possible case. I think 3.5 is much more likely, and it could be as high as 4.0. If you don't want to believe Nissan, consider that GM is staking its reputation on 40 miles from 8kWh. Do the math.

 

[garygid]

Which reputation would that be?

 

[mwalsh]

Your 2.5 miles/kWh looks like an absolutely worst possible case. I think 3.5 is much more likely, and it could be as high as 4.0. If you don't want to believe Nissan, consider that GM is staking its reputation on 40 miles from 8kWh. Do the math.

Was looking for a MINI E thread and thought this was interesting enough to bounce...looks like Planet4ever was right on the money - ~4kWh should be a really easy average to maintain under just about any driving circumstances, if my own time in the LEAF has been anything to go by.

But back to the MINI-E. Does anyone know EXACTLY where they are at with this program. I didn't give them any coverage in my piece on the LAAS because my main criteria was they had to have one out on the show floor. However, they did have one on the Green Car Ride 'n' Drive, but had blocked it out for some reason the whole morning. I didn't put my name down as I wanted to have my test drives done by lunchtime. However, I did notice that it's available afternoon slots filled quickly, so more than a few people must have thought the wait to be worthwhile.

 

[DeaneG]

Hope so too! We'll see. OTOH, the Tesla roadster is probably much lighter then the Leaf and has a much smaller frontal area, helping in both city and freeway efficiency.

Engineering is like lawyering - can't help but to look for all the possible problems. Sorry for repeating myself on the solar thing. I'd like to do it for the entertainment if not the $ savings. Wife won't bite on the quicker house sale idea.

The math is not hard - 70 miles per 24kWh in the battery, 0.85 wall-to-battery charging efficiency:

2.5 miles/kWh = 0.85 * 70 miles / 24kWh