Kawasaki VN 800 Classic Electrification

Started today with my E Motorcycle project. I managed to grab a Kawasaki VN 800 Classic chopper without motor for little money. The previous owner had it already converted to bobber style. I will probably have to undo some of those conversions, as they are a little bit unpractical, for example the fenders which are mounted so close to the tires that a stone stuck in the tire could lead to serious problems. I'm also not a big fan of side-mounted license plates. And the handlebars are a little bit excessive for my taste.

I have a battery made out of 24 Eve LF105 prismatic LFP cells, which gives a 72V battery with a little above 7 kWh. It is managed by a JK BMS B1A24S-15P.

I use a Fardriver ND72680 motor controller. Originally it was supposed to drive a QS 273 8000W hub motor, but I learned that any alteration to the bike frame is gonna cost real big bucks at a test center when you want to get it street legal here in Switzerland, so I also ordered a QS 138, which hasn't arrived yet.

I'm gonna put a 3.3 kW TC Elcon charger on the bike and connect it to a female Type 2 plug, so that I can charge at public AC charging stations.

Today I wired up the basic drivetrain on a Testboard and managed to complete the controller's autolearn mode. The throttle turns the motor and the reverse switch, which is the only other input on the Fardriver I'm going to use, also works. So far so good.

Next up is wiring up the charger.

I have a small problem. I wanted to control the whole system with a three position keyswitch, so that one position is drive and another is charge. But the Fardriver wants battery voltage on its ignition input, and my charge controller wants 12V. Any good ideas?

adsc said:

I have a small problem. I wanted to control the whole system with a three position keyswitch, so that one position is drive and another is charge. But the Fardriver wants battery voltage on its ignition input, and my charge controller wants 12V. Any good ideas?

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I use this idea on my motorcycle as well. I harvest relay switches from the circuitboards of scrap microwaves. Let the "on" position of your ignition fire the coil of the 12v side of the relay, and have the contacts of that relay close the 72v circuit to power on your controller.

If you don't want to harvest scrap parts, a standard automotive relay would work too.

You mean have the DC-DC perma-wired to pos battery and then wire the switch past the DC-DC on the 12V side and let one output close the relay you described, and the other output the 12V to the charge controller?

adsc said:

You mean have the DC-DC perma-wired to pos battery and then wire the switch past the DC-DC on the 12V side and let one output close the relay you described, and the other output the 12V to the charge controller?

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That's one way to do it, there's more than one. Take a look at my simplified wiring diagram to see if you get any ideas from that.

I might just leave the charger permanently enabled. The Charger Control box only turns on when the PP pin is connected on the Type 2 plug, and the whole system doesn't seem to draw any significant current when the Charger Control box is off. Maybe I'll send a park signal to the controller instead of disabling it when it's charging. The Charger Control box has an output that could be used for that.

As I've already written in the Elcon TC Charger thread, I have integrated the charger today into the testboard and successfully charged the battery to full on a regular 230V outlet drawing 10A from it.

Nice project. I'll follow your build and progress. Good luck and enjoy.

I worked a little on the rolling frame today, but only dismounted stuff I don't need and checked the interfaces I'm going to use. Test mounted one of the rotary hall effect throttle units and connected it to the original cable pull throttle and seems to work well. Might have to add a stiffer spring to the rotary throttle unit, though, because the throttle grip is a bit sluggish in rotating back by itself. But the cable length is good.

Other than that I'm only going to use the ignition button for the reverse mode, the stand down switch so that the throttle is dead when the bike is parked, and I'll also wire the motor kill switch into the circuit somehow. The rest of the bike's controls will stay in the original 12V circuit, and I think I'm also going to keep the original 12V battery and just use the DC/DC converter to keep it topped off. I don't even know if I'm gonna bother with regenerative braking. If at all, I'll probably use the throttle release method of regenerative braking.

I'll probably completely remove the original clutch lever. I originally planned to switch the rear drum brake from the foot pedal to the clutch lever, but a motorbike mechanic recommended against it. He thinks you won't be able to enact enough force with your hand on the lever, compared to stomping with a foot on a pedal. I'm not sure about that, because the pedal is not really well positioned for stomping, but I think for getting it street legal, it's better if as much as possible remains original, and otherwise as little is added as possible to keep complexity down.

Something that I noticed that sucks is that the "driving wire" of the original odometer is broken. Could be a bit of a challenge to repair, because it goes directly into the rear wheel sealed assembly. But maybe I'll just bring it to a Kawa workshop, there is one not far from where I live.

I've also been keeping the motor in the test setup running for a longer time. There is of course no load on it, so it only draws 7 amps from the battery, and it took like 5 hours to run the battery down to around 50% (at least that is what the BMS claims). All temps were fine and the cells all stay within a couple mV of voltage.

I've noticed two things that I don't like with the QS 273 motor. First of all, it wobbles slightly when turning. And secondly, it has a very loud high pitched noise at certain RPMs. Maybe that's just because there is no load on it? I've fiddled with the phase offset parameter in Fardriver a bit but haven't really noticed any change. But since I'm not going to use this motor anyway, I'm not that bothered with it. Still curious, though.

adsc said:

I've noticed two things that I don't like with the QS 273 motor. First of all, it wobbles slightly when turning.

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Is there a tire on it, and which way does it wobble? Like a regular motorcycle wheel, you need to balance it, and it's harder to do than a normal wheel, takes some guess-and-test, and more weights than a normal wheel.

adsc said:

And secondly, it has a very loud high pitched noise at certain RPMs. Maybe that's just because there is no load on it?

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That possible could be it, and it also could be the controller.

No, it has no tire yet. The rim edge does move a little bit left and right when the wheel turns rather slowly.

QS 138 has arrived and I've connected it today and tested it out. It doesn't have the high pitched whine that the QS 273 has, so that's positive. It does get pretty hot, though, had it running for about an hour without load and it peaked at 71°C. It's rated for 100°C continuous, though, so not really concerning yet, but much different from the QS 273. Of course it doesn't really tell much as long as there is no load on either motor.

A detail to note is that the 25-8 ring terminals that come preinstalled on the phase wires are too wide/long to fit into the Fardriver 72680 recesses, where you have to connect them. The ring terminal hole is not aligning with the screw hole, but if you cant it a bit and then drive the screw in anyway, it will move back and expand the plastic channel a little bit, so that it does fit in the end and gets good contact. I was a bit concerned at first and already considering installing different ring terminals, but I had some help there and it all worked out in the end.

Now I hope that I can get some help with manufacturing a mounting system for all those components.

adsc said:

Now I hope that I can get some help with manufacturing a mounting system for all those components.

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Looking at your frame, you should be able to adapt what I do, so two simple plates held with the swingarm bolt and one additional bolt through the frame mounting points.

I now have an MDF plate that mounts the motor using the tabs shown in the following pic (not my frame, it just shows the mounting tabs better than on the current pictures I have). The swingarm pivot is also circled in red, and the chain has to clear that, so I decided to stay with original 17T front, 42T rear gearing. There is a spanish shop (mjcorse.com) where you can order sprockets for the 17mm/14mm 6 splines shaft of the QS 138 for different chain pitches/widths and with different teeth counts. Probably going to a 520 chain, because the original 530 chain is massive and I'm worried that the shaft is not long enough for the chain to clear the motor housing with enough leeway.

No idea what thickness of steel to use for the plates, is 6mm mild steel a good idea? The lower tabs are only 5mm I think. Also I have no idea if three bolts for each plate in the tabs shown is stable enough. There is also a centered small flat plate with a hole in the middle (that is only like 5mm deep) sitting on the frame tube going parallel to the swingarm bolt and sitting below it (it's where the lower tabs are mounted to). Maybe I should interface with this plate as well.

I also built some polystyrol foam block models for all the parts I want to mount on the bike (Motor, battery, controller and charger). So expect a pic soon of the actual frame and with those mock models placed.

I love that this build is mostly battery and tiny, high density motor.
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