Test: 200w electric bicycle efficiency = 1512 MPG equivalent

[Gone4]

Originally Posted by diesel_john

I think you may end up quoting miles per dollar to compare with any energy source because the power plant is burning some fuel at probably only 30 to 40% efficiency by the time it get to the battery. So we might want to stay away from any miles per gallon or miles per watt numbers. Evenually miles per unit of energy from any source will be similiar i suppose but until then miles per dollar is about as fair as you could get. Even windmills and pv panels cost dollars. What do you think about this approach?
How do we add enviromental costs to this?

It's quite hard to do that considering the power source varies from place to place. The gas I use versus what they use in down south isn't even the same right now, and ergo has a different amount of energy. Realistically it will vary from station to station based on the amount of ethanol added too. And how would you treat sources such as the captured methane from cow's feces that Vermonter's buy and would otherwise cause more environmental harm? I guess we would get infinite values since it's reducing methane which is many times worse than CO2.

[MetroMPG]

Originally Posted by diesel_john

I think you may end up quoting miles per dollar to compare with any energy source because the power plant is burning some fuel at probably only 30 to 40% efficiency by the time it get to the battery.

"Only?" Even at only 30 to 40% efficiency at the power plant, electric drive is far more efficient than internal combustion.

until then miles per dollar is about as fair as you could get.

That's problematic. Don't forget: some people will pay more for efficiency; the bottom line isn't always cost.

On top of that, people pay anywhere from 5 or 6 cents all the way up to 20+ cents per kWh for electricity, so quoting a MP$ figure for electric falls apart there. The price of fossil fuel doesn't see the same kind of spread across the country (some, but not that much).

[diesel_john]

Originally Posted by MetroMPG

"Only?" Even at only 30 to 40% efficiency at the power plant, electric drive is far more efficient than internal combustion.

That's problematic. Don't forget: some people will pay more for efficiency; the bottom line isn't always cost.
On top of that, people pay anywhere from 5 or 6 cents all the way up to 20+ cents per kWh for electricity, so quoting a MP$ figure for electric falls apart there. The price of fossil fuel doesn't see the same kind of spread across the country (some, but not that much).

I bought a windmill which will take 7 years to pay for itself, just to save from buying 17,500 kw-hrs @ $0.10 over that time. That's the cost I'll pay.

I was just looking at the bigger picture, it's good that electric cars fit the job in a lot of places. But for the sake of comparison the dollar is fairly consistent over the US at least. That's how i will know what some people will pay for efficiency.
If i say my energy cost is 16 miles per $. Then everyone can compare their cost in their location.

Would it be easier to quote miles per kw-hr, rather than trying to figure out how many gallons the power plant had to burn?

Since this post is about an efficiency test of an electric vehicle, I don't know how to convert that to other energy sources for the purpose of comparison.

[jjackstone]

Here is a link to energy unit conversions.
http://www.cogeneration.net/FuelAndE...quivalence.htm

There are many of them out there.
JJ

[diesel_john]

Originally Posted by jjackstone

Here is a link to energy unit conversions.
http://www.cogeneration.net/FuelAndE...quivalence.htm

There are many of them out there.
JJ

I am hinting that to get gallons, i would need to know the efficiency of the power plant and transmission to the battery.
311 watt-hrs / mile i understand.
At my electricity cost that would about 32 miles per $.
In contrast to my car at 16 miles/ $.

[MetroMPG]

Ah, now I see what you're getting at. You're opening that can of worms.

EPA doesn't use power plant or efficiency of transmission to determine MPG equivalent of electrics. It uses power usage from the wall (which factors in charger in/efficiency).

If we're going to force electrics to factor in power plant to wheels, then to be fair we must also change the way we measure fossil/liquid fueled vehicles, ie. factor in energy use in refining and/or transportation of the fuel to the pump.

I think it's best to stick with the way the EPA does it.

[diesel_john]

It would take a team of scientists to calculate the cradle to grave path for a drop of energy. By cost i didn't mean that was the only cost. (e.g. enviromental) i just thought converting to currency would make it easier to compare the direct economic forces. Economics tends to influence the direction unless the feds intervene forcefully. That means we need pioneers like the ecomodders all the more.

[TomEV]

While this thread is a bit dusty, I typically use the dollar/gallon VS btu/kWh because people always ask one of two questions -

How many MPG does it get?

How much does it cost to run?

Unfortunately, most people aren't familiar with btu's or kilowatts.

If you equate MPG based on what it costs to fuel an IC car, VS the price of electricity, than I use the present cost of gasoline (today it is $4.56 / gallon for regular) and the present cost for electricity to charge my EV (6.5 cents / kWh - 80 % geothermal here, balance is other renewables plus natural gas peaker plants).

Using the numbers above, the 'fuel' cost per mile to operate my Citicar is 1.625 cents a mile at 250 watts hours/mile.

It gets about 280 MPG when comparing today's gasoline cost. But as stated, this is a moving target, and has the effect of making electric cars appear more 'efficient' every time the price of gas goes up.

Using the BTU information, it gets 134 MPG. Seems to me that 134 MPG is rather understated... Feels like my 'MPG' is much more than that as the cost per mile is almost nothing.

IMHO it seems that the best way to keep records is watt hours/mile since price is a moving target, but MPG based on the current price of gas is more accessible to the unwashed. Is the standard here to use BTU equivalents?

[ebacherville]

easiest way it to calculate the amount of energy in a gallon of gas , then go by that for your electric usage.. as for the efficiency of the electric plant.. hard to tell unless you ask them and they tell you, usually they're more efficient than a IC engine by a long shot.

[bennelson]

I have been doing my electric motorcycle fuel economy based on converting both gasoline and KWh into BTUs.

Electricity is measured from the wall, which takes charger efficiency into account - which is good, it encourages people to use an efficient charger.

My cost per mile is right about at 1 cent, so figuring economy based on price of gas is real easy - just move the decimal point in the gas prices over two places.

I usually state my economy based on the electric to BTU conversion as stated in MPG - right around 300 MPG. Then I say that "but based on the COST of gasoline, it gets the equivelent of..."

I also mention how electricity can be made from solar, wind, etc. while gasoline cannot.


There really doesn't seem to be any good standard to stating "gas mileage" of an EV to the masses. Watt-hour per mile is good to use for electric vehicle folks, but I think it is worth it to convert to MPG for everyone else.