1964 Honda S600 Motorcycle/Electric hybrid

Alright, cool.

So the story goes like this: I have this motorcycle powered 1964 Honda S600 (seen here: https://www.youtube.com/watch?v=UsbfzmPCYX4) There are a few things I don't love about it, mainly that it doesn't have reverse, but also it could use a few extra horsepower and I'd like to re-do the driveshaft layout. It occurred to me that I could solve all of these problems by adding an electric motor to the powertrain. I've also been wanting to do an electric vehicle build for a while and this seems like a good introduction.

Because of the motorcycle engine location and packaging space, I'll be running the electric motor directly to the driveshaft and the motorcycle engine will be connected with a chain drive to a sprocket on the driveshaft. Max driveshaft RPM is 6500. I have a lot of fabrication and engineering experience, so I'm not worried about the mechanical side.

I'm not sure how much battery I'm going to need; I'm not looking for range so I suspect I will be getting the minimum battery size I need to output the peak 660 amps at 96 volts. Any thoughts on where I should be looking for high discharge current batteries? Used (cheaper) batteries would be preferable.

I'd also like to know if anyone has any experience with this layout: a hybrid setup with the electric motor after the transmission output. I suspect there are some requirements and, uh, nuances of this setup? Any other thoughts are appreciated.

1. Nice to see you here! I am looking at your book on my shelf as I type this.

2. Car pics! An S600 is just about my dream car. I just nearly settled for an N600 a couple years ago. Where'd you find the S600? Cost?

3. Agreed with ditching the gas. Did Hybrid in '11 with TAMU. Integrating the systems well is really tough. Neglecting that, what kind of driveshaft RPM are you seeing? The EVD35 is...70ft-lbs peak? Seems a little weak. If you're wanting to fill in the bottom of the torque curve, the IMA motor isn't a bad choice. Around the same HP, MUCH more torque, and will spin to well over 6000rpm. It has been awhile since I've looked at the chart, but I believe the base speed on 150V is around 3500rpm. Downside is that it is a pancake motor, so thin but larger diameter and you'd have to make end plates for the housing. A size 6 would drive it nicely, though. You could also look at any of the Toyota HSG motors. Again, would have to make the housing, but they are far more torque-dense and are stupid cheap. Neither of those options is plug and play. You'd have to characterize the motor, which is pretty difficult with a Sevcon.

I'm not going to ditch the motorcycle engine; I like it too much! I have no doubt that full electric is better than a hybrid, but for this project, I'm going with a hybrid. The goal is really to add a bit of boost power on top of the ICE, and also add reverse. I'll probably attach the throttle pot to only have the EMotor come in at >50% throttle.

I can't seem to add comments to this thread that have pictures or links without it going to a "moderator review" which never gets reviewed, so sadly, you'll have to use your imagination, or Google, to find videos and pictures of my "Hot Rod Honda S600"

The packaging space I have for the motor is tight, so an IMS won't fit. the EVD35/DLC28 pretty much maxes out my space.

After digging around for battery information, it seems my best bet will be 1/4 of a Volt battery (2 48v modules in series) which will give me a 24s with about 4kWh and enough discharge current to give me short (<10s) bursts of 660 amps. I can't seem to find any reason that a Turnigy TQ4 4x6S hobby charger won't work for me since the battery will be small and since it will also be able to drive on gas alone (in other words, slow charge should still fill an empty battery overnight and I don't foresee being stuck anywhere with an empty battery.)

Actually, that brings up a good question: if I'm not using the motor (PMAC) as a power source, but I am spinning it with the ICE, will it generate electricity whether I want it to or not?

Anyway, I appreciate the comments and concerns. Please keep them coming!

SuperfastMatt said:

I have no doubt that full electric is better than a hybrid, but for this project, I'm going with a hybrid. The goal is really to add a bit of boost power on top of the ICE, and also add reverse.

Click to expand...

A parallel hybrid is an interesting combination with a motorcycle transmission, because it can provide an electrically-powered reverse. Unfortunately, the combination also makes it difficult to incorporate a motor sandwiched between the engine and transmission, and if the motor were coupled to the engine's crankshaft then you wouldn't be able to use the motor for reverse.

Does the car have no reverse now?

SuperfastMatt said:

I'll probably attach the throttle pot to only have the EMotor come in at >50% throttle.

Click to expand...

If you're up for a more sophisticated solution, it would be nice to more smoothly extend the engine's power, rather than just add on like the nitrous. Perhaps you could program motor torque to "top up" the engine torque to a relatively constant level (proportioned to throttle input), across a wide speed range. That would mean it would be used at engine speeds below the torque peak as well as above, extending the effective power band.

To regain battery charge, all the usual hybrid techniques apply: regenerative braking; and sustaining more engine throttle than requested by the pedal, while using the excess power to generate.

Most hybrids are configured to minimize fuel consumption while otherwise maintaining a typical gas-only driving experience. In this case, the target can be complementing the gas engine performance with electric motor performance.

Have you done any combined tractive force plots to see where you're traction-limited? It doesn't make sense to fill in the bottom of the torque curve if you're already traction limited, unless you're using it to remove a shift or two. Maybe go from using 1st (do you use first now?) to start rolling to 3rd?

Thinking more, my approach would probably be to gear it to maximize usable tractive force. That might actually be further up the rpm range. I know the Sevcon is pretty flexible, but I wonder if you can apply torque limits based on RPM. It would be slick to pick a maximum torque (for peak grip on your best surface or slightly over?) so the controller only starts out at say 30% torque, then ramps to 100% as the rpms climb. That would get tricky with shifting, but at least logging the gear is easy with a sequential.

I have tractive force curves from when I originally set up the MC engine gearing, but I don't have the tires characterized, so it doesn't help too much. I have pretty sticky tires so there's still a lot of traction there; I'd like to just max out power on both motors and see what happens, then go from there.

I've done all my mechanical design for motor mounting and power transmission and I think I'm happy with it. It's all packed tightly into the transmission tunnel.



I decided to go with two Chevy Volt modules; they are inexpensive and have a high discharge rate so I can get away with the high amps without having too much battery. They showed up today, so now I need to build an enclosure with a cooling loop. Still need to look into contractors and wiring, I haven't done any research on that.