First Electric Motorcycle Conversion Advice (1974 Honda CB360)

RealPolarBear

10 µW
Joined
Oct 20, 2023
Messages
6
Location
CA/WI
Hello everyone!

I am relatively new to this community and am super excited to learn about electric motorcycle conversions. I have been lurking for a bit to compile a parts list of my own to start my first build. I have done smaller projects with RC cars and electric skateboards so I am familiar with some of the main components that go into a build, but I am looking for more advice.

The motorcycle I’m converting is a 1974 Honda CB360 which came mostly complete (with a non-running motor). The frame, wheels, tires, fork, and swingarm weigh roughly 150-175 lbs (68 - 79 kg). I myself am a 6’ 3” 190 lbs (190.5 cm 86 kg) rider. I would like to be able to cruise at ~55 mph (~88 kph) and do short (<30s) bursts quicker. This bike will be a road commuter where the speed limit doesn’t exceed 45 mph around town. That being said, it would be nice to be able to have some overhead to ride back roads where the speed limit increases to 55 mph. It should be noted that around town, the roads are relatively flat, but outside of town, it can get hilly with inclines at 5-6 degrees (8-11%). These hills are 1 mile long at the VERY most. Usually, they are about half a mile. I would like to have at least 20 miles (32 km) of range around town. Likely, I am probably just going to get a battery that fills the frame well (capacity-wise), so the exact numbers on range are not too important to me. 20 miles just seems like a reasonable minimum.

From snooping around the forums for a bit, I have learned an enormous amount and have started to compile a parts list. I would be very grateful to anyone who can offer any criticism to this list as this is a new experience for me.

Parts:

Motor: QSMOTOR 138 4000W V3 Mid Drive Motor With Gearbox
Controller: SiAECOSYS/VOTOL Programmable EM200-2sp 72V 600A Controller
Battery: Amorge Custom 72v 40ah 200A battery pack with charge indicator

Of course there will be accessories and smaller parts here and there, but currently, I am more concerned with the big expenditures. My budget for the three of these items is about $1700 but I have some wiggle room.

My main questions are:

Controller: Is the VOTOL EM200-2sp a reasonable controller for this build? It is rated at 72 v (which is what I will be running at) and 200 A with boosts capable of 600 A. I am also considering a Fardriver. Would this be a better option? If so, are there any recommendations for a specific controller?

Battery: The Ah are not too important to be right now, I’m more concerned with amps. I believe I should be looking at a battery rated at 200 A with boosts of 240 A. Will this be able to push me up to speed of 50 mph (80 kph) in a reasonable time (<15s)? Or should I be looking to get a battery with higher discharge than this? If so, what are some recommendations that I can ask Amorge for that will be safe on the VOTOL or Fardriver recommendations?

Any feedback and advice y’all have to offer would be extremely appreciated. Thank you in advance :)
 

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I don’t know enough about controller brands or models to help you out with decisions on what to buy, but 72v with 600 amp max load will be far more than enough for a little 4kw motorcycle. Even at the continuous load of 200 amps, it’s capable of 14kw. It’ll still work fine with a lower power motor but it’s just a bit of a waste of money and space unless you plan on upgrading the motor later. I would go for a higher power motor but it might not be necessary. Currently your motor is only a bit over 5 (electric) horsepower, which may get you up to 60 but it’ll be a struggle.
 
Your parts list looks quite close for what you want to accomplish, I don't have major suggestions, as all of the components you suggest are capable of what you're asking from them. You even have a reasonable range expectation of 20 miles, which most newcomers aren't able to expect, as they usually want a lot more than what's reasonable. Also, I'll note that your bike frame is rather similar to mine in many ways, so check out my build if you haven't already for similar expectations. Main difference would be that I used a hub motor, you are looking at a middrive. On that note:
Battery: The Ah are not too important to be right now, I’m more concerned with amps. I believe I should be looking at a battery rated at 200 A with boosts of 240 A. Will this be able to push me up to speed of 50 mph (80 kph) in a reasonable time
Yes, in fact, my frame of a similar weight really only ever sees bursts of 150 amps, maybe 175, so if you build it to handle 200-240, you should be all set, with headroom.
 
I don’t know enough about controller brands or models to help you out with decisions on what to buy, but 72v with 600 amp max load will be far more than enough for a little 4kw motorcycle. Even at the continuous load of 200 amps, it’s capable of 14kw. It’ll still work fine with a lower power motor but it’s just a bit of a waste of money and space unless you plan on upgrading the motor later. I would go for a higher power motor but it might not be necessary. Currently your motor is only a bit over 5 (electric) horsepower, which may get you up to 60 but it’ll be a struggle.
I agree with this, that your current weak point seems to be your motor, but really, only by a little bit. You'll see others on the thread able to regularly get a bit more out of the 138 than it's specs, but you'll have to ask them. I do think you should stick with the controller you have picked out, as in my opinion, it's not always great to be pushing your controller to its max rated specs on a regular basis. I have a 400-amp continuous controller, 600 peak, and as a result it basically never gets more than slightly warm, even where I mounted it with little to no airflow. Overkill, yes, but also equipment safety, in my opinion.
 
I agree with this, that your current weak point seems to be your motor, but really, only by a little bit. You'll see others on the thread able to regularly get a bit more out of the 138 than it's specs, but you'll have to ask them. I do think you should stick with the controller you have picked out, as in my opinion, it's not always great to be pushing your controller to its max rated specs on a regular basis. I have a 400-amp continuous controller, 600 peak, and as a result it basically never gets more than slightly warm, even where I mounted it with little to no airflow. Overkill, yes, but also equipment safety, in my opinion.
Yeah, definitely better to go much higher than you need. Even if the motor is able to produce more power than stock, the original engine on the motorcycle made 30 (peak gasoline) horsepower. Currently the motor planned to be used has the same power as my push mower. Even if you could double the power it would make about as much as a smaller riding mower.
Only way to see if it’ll have enough power is to try it though. I’ve got a 500w (2/3rds HP) scooter that goes 15MPH with ease, and should do 25MPH with a sprocket change. A gas motor with that little power would struggle hard, the lowest you really see on gas scooters is 2 horsepower. So who knows.
 
Sounds like you’re on the right track. The QS138 4k v3 is a great motor. Cruising at 50 mph will drain your battery quickly at those speeds, just keep that in mind when calculating for range. The VOTOL should work just fine. You could always change controllers after the fact, if you don’t like the functions.
 
Thank you all for the quick responses! It's thrilling to see this helpful community engagement. From what I understand, my current limitation is my choice of motor. I originally chose this motor due to its (relatively) compact form factor compared to the next step up qs165 v2 5000w mid drive motor. I seems that the qs138 motor has good power for its size and price. I'm not shy of upgrading in the future, but this is my first entry-level build and I want to keep my goals (and expectations) reasonable. Likewise, I do think it'd be nice to be able to fit a bigger battery (72v 56-60ah 200/240a) battery but I'm going to have to get some more measurements before I consult with Amorge to have it made to fit. I'm no speed demon so having good acceleration and torque in the low range would be preferred, but it would still be nice to top out at ~60 mph (~100 kph) on straight flat roads. To clarify, most of my commuter riding will be at around 35-45 mph (56-72kph), but having the ability to go above that for leisurely rides is preferable.

I've found that the qs138 seems to be a be a good middle ground between power and range tradeoffs, is this generally true? I'd like to be able to get up to my cruising speed (even if it takes a little longer) on the weekends, but it would be a bummer to get to a hill in my area and not have the torque to be able to get up it at 10-15 mph (16-24 kph).

I really appreciate all the feedback!
 
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Your parts list looks quite close for what you want to accomplish, I don't have major suggestions, as all of the components you suggest are capable of what you're asking from them. You even have a reasonable range expectation of 20 miles, which most newcomers aren't able to expect, as they usually want a lot more than what's reasonable. Also, I'll note that your bike frame is rather similar to mine in many ways, so check out my build if you haven't already for similar expectations. Main difference would be that I used a hub motor, you are looking at a middrive. On that note:

Yes, in fact, my frame of a similar weight really only ever sees bursts of 150 amps, maybe 175, so if you build it to handle 200-240, you should be all set, with headroom.
Coincidentally, your bike was one of the first builds that I came across during my research. It's a super sweet bike and has defiantly inspired me to what's out there and what can be done. Your 8000w qs273 is quite the beast paired with that monster battery and controller!
 
Coincidentally, your bike was one of the first builds that I came across during my research. It's a super sweet bike and has defiantly inspired me to what's out there and what can be done. Your 8000w qs273 is quite the beast paired with that monster battery and controller!
Thanks for the compliments. I'd say you're on the right track, you can probably go ahead and get started with your plans. I think you may find you won't be able to hit the top speeds of 50-60mph, for as long as you'd like to sustain it, but I could be wrong. Haven't used that motor.
 
Thanks for the compliments. I'd say you're on the right track, you can probably go ahead and get started with your plans. I think you may find you won't be able to hit the top speeds of 50-60mph, for as long as you'd like to sustain it, but I could be wrong. Haven't used that motor.
Yeah, I think the conclusion I've come to is that a burst of 50-60 mph (80-100 kph) would suffice for me. Any more than that for an extended period of time would drain my battery quick. If my normal riding style is around 45 mph (72 kph) on flat terrain, I think the qs138 4000w v3 is a solid choice to balance power and range. I'll have to report back on the actual speeds I'm able to reach and sustain 😁
 
Also realizing now this thread may have been better suited for the builds thread. Can any admins help with moving this?
 
I used a QS138v3 with an EM150, 60v 150A on my ‘74 Yamaha build. On the flat it did 55-60mph. Put 2000 miles on it, mostly at top speed. Rebuilding now for 70mph. The motor should be fine!
 
I used a QS138v3 with an EM150, 60v 150A on my ‘74 Yamaha build. On the flat it did 55-60mph. Put 2000 miles on it, mostly at top speed. Rebuilding now for 70mph. The motor should be fine!
That's super sweet! It's nice to have the input from some more similar setups. I'd love to see a picture of that build 😁
 
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