440 Mpg!!!
 

You think going slow helps with fuel economy in a gas car, you should see what it does in an electric vehicle!

http://ecomodder.com/forum/fe-graphs/graph67.gif

Your gonna need a new shirt! :)

How slow were you going?

The first ten miles were main roads and mixed traffic - up to 45 mpg.

All the rest was side streets with little traffic.

I was especially looking for 25 and even 15 mph roads.

A real average speed for this entire charge was probably 25 mpg.

I'm not TOO surprised to see a big jump in efficiency at lower speeds on a bike. Next step: Craig Vetter, designer and inventor of the Windjammer fairing and Triumph Hurricane Motorcycle ! :)

Impressive. I was wondering about this myself. I feel inspired to build one now. Just gotta talk the wife into it.

I am not planning on running this far on a single charge again, but it's nice to know I can do it.

The main reason I wouldn't want to is RECHARGE TIME.

I only have a 100 watt charger. Anyone care to do the math between 2.83 KWhrs and 100 watts? Yep, you get about a 28 hour recharge!

I'll go a third as far and recharge overnight, thank you...

I am not planning on upgrading the charger anytime soon. Seems an un-needed cost. However, you can bet I will make sure to have a big enough charger for the car.

Actually, if I end up using the forklift charger, it will be total overkill...

bennelson

Will you post your formula to obtain MPG for your electric bike?

How many minutes/volts/amps to fully charge a dead battery.

Maximum miles for one charge?

Thanks
CB

Wow, that's great mileage, Ben. I'll never run into you if you are on the side streets.

I'm on a motorcycle! I don't want ANYONE to run into me!

Maximum miles is easy. I did an endurance run for that great efficiency. It was 33.5 miles. At that point the voltage told me I was discharged down to 40%. I was still able to drive pretty fast and all, but knew that performance would drop pretty fast after that.

[QUOTEHow many minutes/volts/amps to fully charge a dead battery. CB[/QUOTE]
Well, for starters, you don't charge a dead battery. You charge a partially discharged battery. Running your batteries down really far, and often is a great way to kill them.

My batteries hold 55 amp-hours. If I run them down half way, that's 27.5 amp hours I have to put back in to fully recharge them.

My charger charges at a rate of just over 100 watts. I know from calculations that the cycle uses very close to 100 watt-hours per mile. That means I have to run the charger for one hour for every mile I go.

A gasoline equivelent can be figured out by using a common energy measurement between a gallon of gasoline and a KWh (kilowatt-hour) of energy. 1 KWh of electricity is how much energy you use when you leave a 100 watt lightbulb on for ten hours.

I can do a big long calculation of energy conversion based on that there are 125,000 BTUs in a gallon of gasoline and 3400 BTUs in a KWh of electricity, or I can round ever so slightly and say that there 37 Kwhs in a gallon of gasoline.

I have a killawatt plugged into my garage which measures how much energy I use to recharge the cycle. Once the cycle is charged, the green light on the charger goes on. Then I look at the Killawatt and see how much energy was used. Lets say it was 1.5 kilowatt-hours. Divide 1.5 by 37 to see what part of a gallon of gasoline was used. You get .0405 of a gallon. a very small amount. Now divide your miles by your gallons to get Miles-Per-Gallon. Lets say the trip odometer read 13.5 miles. Divide 13.5 by .0405 to get 333 and a third miles.

Writing this all down and explaining it is way longer and more complicated than actually doing it.

Divide Killawatt measurement by 37, then divide your trip odometer by the amount you got. That's your eMPG.


Of course, there are other things that really aren't fair to compare. You can't make gasoline from solar or wind for example. I am also measuring electricity at the wall, so how efficient or not the charger is is important.

No, I am not calculating how much electricity is lost in transmission lines, but I am also not measuring how much diesel fuel is burned to move a tanker ship of petroleum across the ocean. Just trying to measure the energy used by the vehicle.

Pardon any simple math or rounding errors. Just trying to use easy numbers for simplicity's sake. I use the full BTU numbers when doing the calculations for the cycles fuel economy.

A good source of info for converting forms of energy into each is Peak Oil: Life After the Oil Crash

I also have an energy conversion widget running on my Mac. It's pretty slick, but it doesn't do gasoline into KWhs of electricity. Gotta do that myself.

bennelson,

Thanks for the detailed explanation.

Good job.

CB

Check my fuel economy chart again.

The last run was 295 eMPG. What a drop!

I was wondering if maybe my brake pedal was sticking!

After thinking about it, that ride was all north of my house, where the speed limits are 45 and 55 MPH.

The air pushes back a LOT harder at 45 than 25 mph!!! Enough that on my electric vehicle, it reduces my "economy" by 25%.

(That's not quite the full story, Peukert's law also is in play here.)

"The last run was 295 eMPG. What a drop!"

Living proof of the trusim "Aerodynamic Drag increases as a square of the velocity". :)

but but but you claimed "MPG" on this thread title. I was mislead. I like the eMPG designation for those of you don't actually USE gasoline and are calculating the conversion.

adios

Using the calculation, my last charge got me 163.4 eMPG. (226 wh/mile)

One thing I have noticed is that with longer trips, my wh/mile improves. If I only go a mile or so, then recharge, my wh/mile value is just above 300. On 10 mile trips, the value is normally around 260 or so.

This particular charge was exceptionally low, but perhaps I wasn't driving as fast... (fast is a relative term in a Citicar...) :rolleyes:

The fact that we're in the "Fossil Fuel Free" forum might have been a hint it wasn't a thread about gasoline ;)

TomEV: I've noticed the same thing. The farther I go on a charge, the higher my efficiency. It makes sense for a few reasons:

1) Just as with and ICE vehicle, rolling & mechanical resistance decreases somewhat as the tires/bearings/transaxle fluids (if you've got one) warm up, and they'll warm more on a longer trip.

2) But the biggest difference I think has to do with the charger, and measuring energy use at the wall plug. From the point of view of the charger, the most energy efficient charging stage is the bulk phase; the least is the finishing phase (battery resistance rises with voltage, if I recall). If you do short trips and spend proportionately more charging time in the finishing phase, efficiency will apparently decline.

If we could measure energy efficiency of just the vehicle (e.g. from the pack), I'm sure we'd find the swings are much smaller on short vs. long distances traveled compared to readings at the wall.

I have noticed the same thing in terms of range and efficiency.

Most of my ev rides are about 10 to 15 miles. This seems to put me right into the middle of the battery pack - bulk charging stage.

It also doesn't hurt that my current EV is only 400 lbs. The Metro is going to weigh a little more!

Well, I’m not going to be able to take it away from you if you are conscious!