How many miles / gallon are you getting with your electric bicycle?
Last weekend I attended a talk by the CEO of Coulomb Technologies. They're making charging stations meant to be deployed around a city for electric vehicle drivers to use. He had an extremely interesting presentation, and it gave me the topics for a series of blog posts.
This first Equating "fuel" efficiency between electric, hybrid, and gasoline vehicles tries to answer the efficiency of an EV over a gas vehicle. For instance Tesla claims its Roadster gets 190 miles/gallon equivalent efficiency.
It seems my electric motorcycle gets 112 miles/gallon and my electric bicycle gets 1120 miles/gallon.
Okay electricity isn't measured in gallons that involves some conversion factors.
Curious what y'all's thoughts are...
I think the gov is already working on carbon credits ?? I think you need to convert watthr to joules and add the efishency of the generation, transport loss etc. then do the same for any other form of transportation and start an argument with big oil's sceintest's and ev scientist's LaTeR
I agree with your article and feel we need to concentrate on the most efficient way to as you say, "transport our butts around town". It seems to me the better measurement to use is cost per mile. If I compare my mini van with my Pontiac Sunfire the van gets about 20 mpg and the Pontiac gets about 32 mpg. Another way to do this is to compare the cost per mile. If I use $2.oo per gallon then the Van cost $.10 per mile and the Pontiac cost $.06667 per mile. Now if I take this to my electric bike I can calculate the cost in electricity per mile, about $.0012 per mile, and have a figure which can be compared to see which is the most efficient way to transport my butt around town. Of course this is for the cost of the fuel used and not any maintenance that may be required. I still think this gives us a meaningful way to compare transportation options.
Grandpa Chas S.
To get a fair cost comparison, you would have to include the cost per "gallon" of battery power to include the various state, local and federal tax or exclude it on the ICE fuel.
Good point. You are right because there are several taxes placed on the gallon of gas for road tax both federal and state. I guess Uncle Sam will find a way to get road tax for the electricity as well. So if we use this I can still do the comparison. I live on a farm and purchase fuel for my tractors, trucks, generator, etc. and pay $.67 a gallon. This is what you would pay without the extra taxes. 20 mpg at $.67 per gallon = $.0335 per mile. Again I am not including the maintenance which would be much higher for an ICE vehicle than an electric. For the 32 mpg the cost would be $.0209 per mile.
Does this make it more fair?
Grandpa Chas S.
I think the only real way to compare different vehicles is by cost per mile, total cost, everything down to the helmet. My ballpark numbers for an Ice car that gets 25mpg are around $.35 per mile. 125cc Ice scooter, $.26 per mile. My electric bike is $.11 per mile.
Energy only costs considered, the ebike goes 20 miles on ten cents. the scooter goes about three miles, and the car about a mile and a quarter. So the ebike, asuming 2 buck gas, gets 400 miles per equivilant cost per gallon. Last summer that number was 800 miles.
In my opinion, many of these calculations are misguided. The real benefit is ultimately reduced carbon but certainly not cost. Here's why. As a Vectrix owner, I am driving 30 miles using about 4.5kWh for a recharge which equals about 1.5 cent per mile at our electric rate of 10c/kwh. (Note that efficiencey of recharge is about 66%, i.e. to recharge 1kW you draw about 1.5 kW) That sound great as this would equate to about 125mpg at $2 per gallon. However, this number crushes as we take into account the cost of battery use. The pack is estimated to deliver 50,000 miles and I would think that this is very optimisitic. But lets assume that to be true, that adds 16.7cent/mile of battery cost for a total of roughly 18c/mile. Now at at current gas sprices ($2gallon) that is about 11-12 miles/gallon! Thats pretty ad is it not? That's as bad as a Hummer or Dodge pickup truck.
While this is the calculation for the Vectrix, other bikes will come out roughly similar. Cheaper batteries dont give you 50,000 miles and will cost proportionally the same. I am interested to hear what others have to say.
In spite of all that, I love my Vectrix!
I put up a post on the economic and energy efficiency of my e-max scooter in the summer of 2007:
At that time, the basis for comparison was US$3.00 per gallon for gasoline. This is still realistic and will even be low unless we are entering a full-blown economic depression (unfortunately, very arguable this point). At any rate, 92US octane is usually recommended for small-displacement scooter engines so the price is still about right.
My electric scooter achieved 290 mpg economic equivalent and 390 mpg energy equivalent (counting only the energy content of the gasoline, not the transportation and refining).
It also gets about 160 carbon-equivalent mpg for typical US electricity generation.
But the SLA battery pack costs were the real killer of the economics. About 50% of the batteries had to be replaced at about 2500 mile intervals. That costs about $200 for good-quality batteries, so that adds another 8 cents per mile. That brings it down to just 33 miles per gallon, using the $3.00 per gallon basis.
With metals prices dropping, SLA's are getting cheaper, but not enough to lower the cost to an equivalent IC scooter. It is still way ahead compared to the Vectrix battery pack if Harry's numbers are correct. But we are comparing 50 or at best 150 cc class scooters, not 350-400 cc like the Vectrix.
I've since changed over to Thundersky LiFePO4 and will run new tests when warm weather returns. These cheap, but so far reliable, LiFePO4's have the potential to lower battery pack costs down to about 2-3 cents per mile, and their price is going down all the time - assuming they survive the big Phostech patent/trade agreement fights that are brewing - only time will tell.
That is why I like to think in terms of total cost per mile, that way you include the battery replacement, helmet, protective clothes, estimated repairs, insurance, etc etc etc. It's pretty clear the only really cheap transport is slow, as in the ebike, but gas or electric, a motorcycle is much cheaper to run than a car.
While it is fun to speak of getting to work and back on ten cents, I talk to people in real costs, about three bucks per day to ride my ebike vs about 15 bucks to drive the car.
From the blog post:
"Electricity is held in a battery but neither the size nor weight of the battery changes as the battery discharges."
Actually, I don't think this is quite right if you consider relativistic effects. Remember E = Mc^2 or M = E/C^2 So a battery with one KWH of charge (3.6 million Joules) gets about 4 x 10^-8 grams lighter as it is discharged. :)
ah but the electrons return to the positive electrode of the battery at the same rate as they leave the negative electrode.
so 4 x 10^-8 grams is just how much weight is transfered from the negative electrode to the positive :P
The pack is estimated to deliver 50,000 miles and I would think that this is very optimisitic. But lets assume that to be true, that adds 16.7cent/mile of battery cost for a total of roughly 18c/mile.
So do you mean the replacement battery would cost US$ 8350.- ???
if you are comparing ICE and EV operating costs, you have to include servicing, and part end of life replacement.
when i was driving my honda prelude around daily (20'000km/yr) it used to cost me $3500/yr, including fuel and servicing, but not including things like insurance and rego.
so that works out to 0.175c/km (or 28c/mile)
over the past 16'000km (9940 miles), my emax has saved me $2400 ($2800 - $400 for things like tyres and another $125 for electricity, but i dont pay for that :p), against an initial purchase and upgrade cost of $7-8000
so its a 3rd the way breaking even (i dont consider it to have *any* resale value)
i would note that i could redo the bike for around $4200, since prices have fallen since i first upgraded the emax.
my emax gets 57.9 wh/km (93.2wh/mile) measured at the power point.
it uses 43wh/km (69wh/mile) from the battery
i spend most of the time at 70kmh (43mph)
US8350 for a 133v 30AH battery?
blimey, i knew ni-mh was expensive, but thats extreme.
itd be cheaper to buy LifeBatt LiFePO4, and take the power and energy gains with BMS
"Cheeper" for most people means "better". EV's are more expensive now but if people want them then more manufacture should make them and the price should go down. Right? Batteries need special chemical components, so does gasoline. ICE's can have up to hundreds of moving parts, electric motors only have one. EV's need special electronic controllers, but fuel injected ICE's have them too. ICE vehicles need transmissions, oil changes, etc, EV's don't. You have to pay someone to make gasoline, PV's and wind and water generators give free electricity. The EV should be theoretically cheeper to make and use.
I think that if there existed two identical worlds and if in one they went with EV's and the other ICE' vehicles the vehicles in the EV world would by now be better and cheeper than the ones in the ICE world. (Funny that ICE can also be something cold or mean "in case of emergency")
Sign me up for some of that "free" pv energy. Oh right, the energy is free, it's just that the panels cost a thou per 200 watts.