View Full Version : My first EV conversion

12 July 2016, 0953
Hello All,
I recently finished converting a 1986 Ninja 600. After a friend showed me some home EV conversions online, I decided to jump in. After about a year of on and off work, I have myself a working electric motorcycle and I love it.

One problem I am having is that I am not getting the top speed I expected to get. I would love any advice on the subject. Here’s my setup:

Motor: Mars ME1003 - 72v max, 200 amps continuous
Controller: Alltrax AXE 7245 - 72v max, 450 amp peak
Throttle: Magura 0-5k Ohm
Batteries (60v system): 20x LiFePO4 60ah cells (pack voltage is about 66v)
Gear Ratio: 6:1 - 72T rear, 12T front

I am getting a top speed on flat ground of about 35mph and less going up modest hills. Based on other posts here and info on evalbum, that seems slow for my components. Any insight on that?

Given this is my first venture into electric vehicles, there is a good chance I have made some mistakes, so any advice is welcome! Thanks!

12 July 2016, 1409
Some years ago I had a 2009 Electric Motorsport GPR-S that had a similar drive train, voltage and batteries. That bike was good for a top speed of 65 mph and a range of between 20 and 35 miles, depending upon the speed traveled. I don't know what the gear ratio was and I am sure it never saw 200 amps. I think around 120 was typical when using full throttle. Anything more and the voltage of the 20, 50-Ah, Hi Power batteries would sag.

12 July 2016, 2128
Maybe you did it right. Do you have a schematic diagram or any other build info we could look at?

Is adding batteries an option? If not, I would at least try a bigger front sprocket. Even if you went up to 18T front, you would still have a 4:1 ratio.

Have you tested the throttle to confirm it is showing 5kOhms at full? Do you have a steady green light on the controller? Just throwing out ideas...

Most importantly, are you going to show us any pictures? My first motorcycle was a 1986 Ninja 600. Can't believe I didn't kill myself. Welcome!

13 July 2016, 0616
Thanks for the replies!
@Richard, the specs you are mentioning is roughly what I was shooting for, so hopefully I am on the right track. I still need to check the amp draw at full throttle. I didn't have the ammeter mounted yet when I took it out.

@Lunchbag, More batteries is a possibility eventually, but it was a cost decision and given that I just want the bike for light, around town use, it didn't seem necessary... yet. I haven't tested the throttle, but that's a good point. The controller seems fine, but I will double check that, as well. Maybe it is just a gear ratio issue. I'll look into swapping out the front and see what I get.

As for photos, most of what I have are close ups during the build, so I need to get better ones now that it is near finished. Definitely not finished with the body, but I'll post a couple shortly.

13 July 2016, 1021
Here's a couple photos in it's current state.


13 July 2016, 1137
Are these the type of batteries you are using? http://www.electriccarpartscompany.com/New-Energy-60Ah-Aluminum-Encased-Battery

13 July 2016, 1632
I did a similar conversion in 2009 using lead acid and I could get to 50mph. Your batteries should be much better.

Where in Baltimore are you? I'm in College Park.

14 July 2016, 1022
@ElMotoMike, yes sir, those are the batteries.

@electrikat, I am in Lutherville. Baltimore County, just north of the city.

I have ordered a new sprocket to see if the gear ratio change will take care of it. I'm still not sure there isn't something else wrong and I'm not sure I'll have enough acceleration with the gear ratio change, but I gotta start somewhere!

14 July 2016, 1419
Lutherville, right near Towson. I don't find myself up that way too often, but I'd love to see the bike sometime. Unfortunately, my bike is in pieces and I've given up on rebuilding it.

25 July 2016, 1015
Well, I got a new 16T front sprocket giving me 4.5:1 ratio and it is definitely much better. And I don't have much lag in power up hills that I was worried about. I may even go up to an 18T. Thanks for the suggestion, Lunchbag!

ElectriKAT, it's nice to hear of another enthusiast in my general area. Too bad you aren't rebuilding, but maybe we could meet up sometime.