1994 Suzuki RF600 Senior Design project Leaf conversion

[jhaggerty]

Hello all,

I've been trying (and failing) for a few months to sign up for Elmoto. I guess I kept missing either the registration email link or the need to post within a week, but whatever it was now I'm here.

I'm a senior in undergraduate mechanical engineering at a state school in New York, and have been interested in EV's and particularly electric motorcycles since I started riding 5 years ago. I've done plenty of work on my current rides: a suzuki DR650 with scads of fun modifications, and a '94 klx250 that I converted to a dualsport through the vermont titling loophole. I'm now working on converting a 1994 RF600 as a senior design project for school.

Two friends in electrical engineering are working on the display, motor controller and BMS design and my focus is on the battery packaging and layout of the components as well as sizing the motor. I'm a bit wary of a homebuilt controller, but have confidence in my teammates abilities and have a backup plan of finding a used alltrax controller if all doesn't go well. The criteria for the project is a range of about 50 miles with a top speed capable of 65mph and decent acceleration. We've decided to go with a brushed DC motor for a simpler motor controller build and a pack size of 12-14 Nissan leaf modules to hopefully get the range we're looking for. I'm not entirely fluent in the battery management system my teammate has come up with, but from what I understand it's a master-slave arrangement with the slave board capable of handling 12 cells each with top balancing (not modules, he'll have to use the sense terminals of the leaf batteries because the boards are limited to 5V inputs). He's basing his motor controller design off of Electric Motovlog's build on youtube and I'm hoping it works out.

We got our bike for a good price from an inmate on the Advrider forums who happened to be from my hometown, and assuming our BMS and motorcontroller end up working most of our out of pocket budget will be going to batteries, a motor and charging equipment. This whole ordeal is fairly daunting as a first time experience as many others have said, but I hope that we are able to have a running bike in the end.

[flo]

Hi
welcome and good luck with your project.
flo

[jhaggerty]

For the battery packaging I am considering whether the mounting frames also have to replace the engine as a tension member seeing as the boxed steel frame of the RF600 is fairly bulky. I know on ninja 250 builds this has been an issue, where the battery frames have to be strong enough to not deflect and to prevent the ninja frame from bending. I really really like the work that this guy did on his ninja, and the overall packaging of the bike was beautiful http://elmoto.net/showthread.php?t=3915&page=12 .
The on paper idea I like most so far is this:


but have also been considering the idea of two larger bent pieces of aluminum plate on either side of the battery pack that also function as the motor mounting plate, loosely based off of this guy: https://rgelectric.wordpress.com/

[Ted Dillard]

NICE! Welcome!

[jhaggerty]

This is the preliminary design for the battery frames:

[jhaggerty]

Some photos from the battery box build.







After powdercoating:

[jhaggerty]

https://lh3.googleusercontent.com/Wy...xY8Bss4o=w2400

This is the first ride after switching from custom built motor controller and BMS to an off the shelf Kelly KDHE 600 Amp version. People may have mixed opinions on these controllers, but compared to our homemade bare bones controller I feel much safer with this.

[jhaggerty]

Dad helping me lay out the mounting plate made out of an aluminum drawer.

[jhaggerty]

Hey all, I have some major updates. Since I couldn't figure out photo hosting before, I gave up on updating this thread. Additionally, professors at school were being a PITA about approving our project, but that turned around in the end (details to follow later.)

I plan on going into detail in the reserved spots above, so if this doesn't make sense chronologically down the line it's because I went back and filled in more info in posts 6,7 and 8.

Currently the bike is assembled and driveable! Though I had some major range problems on my first ride that I could use input on.

Specs:

1996 suzuki RF600
Mars Energy ME1003 Motor
Kelly KDHE600A 120V controller
Throttle cable pull to hall converter https://www.aliexpress.com/item/3292...15504c4d3UylAF
14 nissan leaf cells in series (117V max, 103.6 nominal)
GS500 front wheel and pyramid parts conversion bearings P/N 09262-17034-000 (takes 15mm axle of GS to 17mm axle of RF)
2 Eltek Valere 110-125VDC flatpack 2HE 2000W rectifiers as chargers
EVC500 contactor by TE connectivity
ANL 500A fuse (this needs to change- it's not rated for my pack voltage)
LED turn signal relay, signals, and taillight from Amazon
Streetfighter headlight from amazon w/ 65W phillips bulb
96V dC/DC from Thunderstruck motors allowable input up to 120V, peak burst current 50A
Cycle Analyst V2.4 with remote shunt
-------------------------------------------------
12 tooth front sprocket ANSI 40 from Mcmaster
48 tooth rear sprocket
530 chain
^^These things I believe I really need to change- my gearing ratio is about 4:1 which at 72V puts top speed at 69mph... and that's without overvolting^^

--------------------------------------------------
Not yet installed:
ANT SmartBMS https://www.aliexpress.com/item/3282...15504c4d3UylAF (thread on these here: https://endless-sphere.com/forums/vi...t=32S#p1361253) I plan to upgrade components in this and potentially run pack amperage through it with conservative testing and a fire extinguisher on hand...
JS1772 Inlet
AVC2 unit for allowing J1772 standard to work
second throttle cable to hall converter for variable regenerative braking

This picture is from before switching to off the shelf controller and the new front wheel, but it is essentially what the bike currently looks like:


Problem summary:

I took the first real ride with the bike a few days ago. The pack was at about 4.1V per cell and the controller set to full amps and full voltage. It rode very well, with good acceleration in the mid range, high top speed and okay low acceleration. Long story short It went 25 miles before hitting the LVC of the motor, which I have set to 84V (3V/cell). The Cycle Analyst showed 35AH used, max draw of about 450 amps (a quick burst racing my dad) and about 140 wh/mile. I was pretty bummed to say the least.

I spent the next day paralleling the modules and putting them on a small RC charger to make sure they were evened out before bulk charging. The first stack evened out nicely with 50AH from the RC charger. After Bulk charging all but two of the 7 modules were dead on 4.1V. The second stack I didn't leave paralleled as long, and when bulk charging the voltages were fairly out. One module reached 4.2V, which I drained back down using a 12V motorcycle headlight bulb. Needless to say all of this will be easier with a BMS.

The kicker to me was when I bulk charged the second stack had it run through the CA to see input AH. The total was about 32AH from bulk, plus about 4AH from the RC charger. 36AH on a "66AH" pack didn't sit well. I'm hoping that this is because I bulk charged to 4.1V, not 4.2 and that I have the LVC set a bit high due to not having a BMS right now.

[jhaggerty]

What I could use some input on is the effect that my tall gearing may be having on amperage to my motor and overall efficiency. When we were doing this for the school project I did some rough calculations trying to use the elmoto spreadsheet but I didn't understand it very well. What I overlooked there was the basic top speed calculation using the rated max RPM of the motor.

With my current setup, assuming 3600 max RPM (no overvolting the motor)
48/12*6.83ft/revolution*3600rev/min*1/5280ft/mile*60min/hr =69 mph top speed

assuming I let the controller overvolt the motor a little and set my top speed goal to 60 mph I think I would be pushing less amps through the motor at the speeds I intend on riding, which I assume would increase efficiency. The motor was definitely warm after the ride, and that was with it's fan running. The batteries were also slightly warm. I think I have to be more conservative with the current limit of the controller.

Feel free to give suggestions on increasing efficiency and usable AH. Right now I am considering gearing and limiting controller current as well as acquiring more test data at a less spirited riding pace. I was hoping to get about 50 miles of usable range at 0-80% charging.