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[Trappist]

Hi First of all, this is my first message, just joined the forum as I'm looking into investing into electric motorcycle. The project is bigger than simply that, I'm trying to even get support from my company, not to pay for the bike but to at least be able to charge it during my working hours to guarantee I have enough "juice" to come back home !
My ride is about 25miles so not too long and normally feasible on one charge, but I might not take the risk, especially at first !
I'm also building the case, we're ~1700 on the site and I would be the first one to go full electric to my knowledge (I'm in Europe), so this would be a nice effort to go sustainable and green as biking is not easily feasible due to the distance, and traffic jams in a car is too much of a hassle - the e-motorbike represent the best solution I can see so far.

So my question is simple, how do we calculate the cost of recharging a motorcycle ?
Choice of motorcycles in Europe is highly limited... I can potentially find zero or GPR-s, Brammo replied they would have some available end of this year and all models later in 2012, this is too late for me.  Right now, leaning towards the GPR-s with a good offer on a 72v 50A engine... So 3.6kW battery.

Any help and guidance would be great I tried to search on the forum, not found anything, but this is easy to miss I guess. Don't hesitate to point me to an existing post if you know it.

[electrc109]

http://electricmotorcycleforum.com/boards/index.php?topic=1510.0

[Trappist]

Thanks
a few more questions though. the measures show how much volts/amps/watts you get at a certain point, how do I extrapolate how much a full charge would cost me ? multiplying by 8h of charging time ? which would give me 1kW*8 = 8kW to charge a 3.6kW battery ? seems a bit strange to me. I might be missing something here 

[frodus]

measure it:
kill a watt
http://www.p3international.com/products/special/P4400/P4400-CE.html

[Trappist]

this could be useful if I had the bike already... but I'm building the case first as it makes no sense for me to buy if my employer doesn't provide me charging facility, I'm too far out from the range back and forth
So I'm trying to illustrate to them how much this could cost them and then buying it most probably within a month's time

[electrc109]

The charger will have a rating on it that indicates how much amperage it will draw.  This will be the most it could consume while in use.  Convert to wattage and figure how long it will take to charge.  If its 1kw over three hours and your electricity costs $.25 per kwh then it'll cost you $.75, for example.

[Trappist]

correct I'll check if this is given in the tech specs, but i guess it wasn't since this is something I checked upfront.

[frodus]

72v 50Ah on a GPR-s is 3.6kwh. If you discharge 100% (which you shouldn't), you'd need a little more than 3.6kwh put back in. Lets say 4kwh (battery chemical conversion inefficiency, BMS draw, charger inefficiency, etc).

If you used a 1000W charger, you'd charge in 4-5 hours, lets say 5 hours. Thats ~5kwh (the last hour is slow, and low current, but lets go worst case and say the charger sucks and it still uses 1000W even it it only puts out 500W during the last part of the charge).

So, lets say you're paying 10 cents/kwh, that's about $0.50 to charge your bike.

Repeat for a 500W charger:
4kwh, you'd need to charge for about 8-9h, so that'd still only be about 5kwh (slightly less), since you're only using 1/2kW per hour, so $0.05 an hour.

So if you get 25 miles on 3.6kwh, and you pay 50 cents to charge, you're gonna get around $0.02 a mile.....

these are all made up numbers, but they're pretty close to what you'd expect. I know here in the states, some areas offer tax incentives for installing a charging station, or incentives for building/buying an electric vehicle..... so check into that.

[Trappist]

Thanks a lot ! You're confirming the initial assumptions I made were spot on I probably did not add much safety margin so I'll follow your advice FYI electricity cost here is 0.19€ per kWh but our gas cost is roughly 11$ per gallon ! So electric makes a lot of sense for me compared to car (different compared to a combustion bike as mileage is higher)

Now i just need to finalize building my case at work, align with HR any in incetives and work with building services to get a plug and always get charged, avoiding completel discharging my batteries

You guys are great support, thanks again. I'll keep you posted on the progress