Hi just wanted to introduce myself. My name is Greg I’m from Sacramento, California and I am at the dream & research phase of my electric motorcycle conversion. Looking for a cheap donor bike, and putting together notes on motors, batteries, controllers, etc.
GOAL: My commute to work is only 9 miles each way, so it seems very duable to build an electric motorcycle to have at least a 20 plus mile range with a respectable top speed. Hopefully 65 MPH so I can cross the river on a highway bridge and not get ran over.
Ok, so I picked up a 1989 Suzuki GSX600F Katana (soon to be Wattana) off of Craigslist for $300, it has an engine knock. I plan on parting out all the bits I don’t need to offset my costs.
That is a nice buy, and your gaol seems feasable, Good luck I hope you keep us informed with lots of pictures on the progress.
new dawn, as in the dawning of a new era:cool:
20 mile range and 65 MPH is a pretty big goal. Realistically you are going to need 30 miles to have reserve. Assuming you can obtain 200 wh/mile means a 6000 watt-hour battery. At 24 volts that comes out to a 250 AH battery pack. With a density of say 130 wh.kg you are looking at a battery weight of 47 kg (115 pounds)
I should have been more clear, my distance is 20 miles round trip to work, with a short span over a highway bridge, so for the most part I will be going 35 to 45 MPH with a short burst of highway speed of 65 MPH to cross the bridge over the river 300 yards maybe
I plan on using the MARS ME0709 motor which I hear can do the job, and I plan on a 72 volt system, 6 batteries in a series with an Alltrax 7234 controller, not sure what batteries yet, but not lithium do to price
[QUOTE=Gregski;6610]I should have been more clear, my distance is 20 miles[/QUOTE]I understand but you will have to design for 30 miles or you will be pushing your bike comming home for the last few miles.
I plan on using the MARS ME0709 motor which I hear can do the job, and I plan on a 72 volt system, 6 batteries in a series with an Alltrax 7234 controller, not sure what batteries yet, but not lithium do to price
Voltage is irelevent, Watt-Hour capacity, wieght, and size is what is important and the measure is wh/kg ratio.
Again assuming you can achieve 200 watt-hours per mile (200 wh/mile) to have a 30 mile range requires 300 miles x 200 wh/mile = 6000 watt-hours battery capacity at whatever voltage you want.
But here is the problem; power density of Lead Acid batteries ratio is 30 wh/kg to 50 wh/kg or to get 6000 wh is 200 kg (440 pounds) to 120 kg (264 pounds. Lithium ion density ranges from 150 wh/kg to 190 wh/kg or at 6000 wh is 40 kg (88 pounds) to 32 kg (70 pounds)
You may not have much of a choice other than lithium Ion. As you might not have the luxury of space and weight to afford to do what you want with less expensive LA batteries.
[QUOTE=Gregski;6613]According to EVAlbum.com 20 to 30 miles is reasonable on lead acid batteries guys are doing it already.[/QUOTE]Gregski I never meant it could not be done with Lead Acid batteries. I was just pointing out the most important factor is energy density or wh/kg is the key to the design. For a given watt-hour capacity on average using lead acid will take 3 to 4 times more weight and twice the space of Litium Ion. Good luck to you and keep us posted on the project.
When it comes to controllers should I get the Alltrax 7234 which is the 300 amp one or the 7245 which is 450 amps to go along with my Mars ME0709 motor capable of 300 amps peak and 125 amps continuous in a 72 volt system? Majority of my 20 mile round trip commute will be at city street speeds 40 mph with a short highway 65 mph burst over a bridge.
Due to the motors low inductance I would go with the larger controller.
Something that catches my eye with this motor is it is failrly low RPM, which tells me it is better suited for high torque for hill and load pulling in something like a utility vehicle.
My golf cart uses 48 volts and a GE Raptor D398 motor with 9 HP cont and it is a speed motor and the RPM is 7200, twice that of what you are choosing.
You might want to call the manufacture and tell them what you are doing and see what they say. Most of th emanufactures or rebuild houses will do the math for you and suggest motor/controller combos.
LiFePo is the battery of choice today. You can use lead acid but use the highest amp hour you can fit. I would use the larger controller as the amp rating is the top limit and you will usually run much below the rating. top speed is result of power and gearing in combo.
Either controller will work, the 300 amp controller should be fine for your application and will be the most cost effective, but if you plan on pushing the limits of the motor or perhaps someday upgrading to a more powerful system you could buy the 450 amp controller and set it to limit the maximum current to 300. Also fyi I have LiFePO4 cells for sale on my website for reasonable prices that might make you think twice about SLA’s. If you have any questions about batteries feel free to let me know.
