# Honda CB360 turned e-bicycle



## rcavictim (Apr 26, 2009)

Hi,

I found a 1974 Honda CB360 twin at a scrapyard and had thoughts of making an e-bike from it so I tossed it in my trunk and hauled it home. About a year later (two years ago) I managed to score a whole whack of well used 105AH 12 volt AGM batteries from a telco installation. These batteries weigh 100 lbs each. I modified the frame of the bike by extending the engine compartment by 12 inches and lowering it 4" to help with c-of-g. The pictures here show the bike after frame mods. The seat was something I had from a rowing exercise machine but is going to be replaced with a larger one which I shall make myself. The spokes had some surface rust in places so I decided to sandblast them as well as the frame and go with a red monocolor paint scheme. So now as I just turn 55, I am very proud to have a nice shiny new red bicycle! 

The power comes from a 25 amp, 28 volt (700 watt) aircraft generator circa 1950's. I made a custom PWM controller for it based on the SG3524 chip and four 60 amp 400 volt Mosfets. I had a curious instability in the controller and after adding circuit filters didn't work it occured to me the problem was because the case of the motor, and thus the whole bike and the controller box is connected to the pulse modulated controller output terminal. The circuit feedback was from the controller case acting as a shield, but the shield was being modulated! Duh. All fixed now. I apply full 48 volts to the armature via PWM and select a fixed 12 volt (for speed) or 36 volt (for climbing hills) to the field. This is like having a 2 speed transmission. The bike is so enormously heavy with the 400 lbs worth of batteries  that I needed a gear ratio of around 22:1 to move it properly. This is achieved by #40 roller chain sprocket reduction and a gearbox driven via lovejoy coupling from the high speed motor shaft. The motor, gearbox and rear wheel axle all pivot in geometric synchronizm on the rear axle forks. A second smaller gauge standard bicycle chain connects from a separate sprocket on the rear wheel to a sprocket with sprag included to the pedal shaft up front. The pedals are not powered around from forward motion of the bike which would have been very dangerous. 

This setup gives me a top speed at 48 volts that equals the law limit of 20 MPH in the hi-speed (12 volt) field setting. I did one short road test 2 years ago with 3 batteries and a knife switch while figuring the gearing and in the final configuration. Acceleration is excellent.

Since building this the batteries deteriorated and I never did get it on the road yet as it is not quite finished. This past week I scored a bunch of like new Hawker SBS60 51 AH 12 volt AGM batteries. Four of these are going into the bike to replace the original set. These new batteries are much smaller but fit the space I made well and at 41 lbs. each my battery pack now weighs 164 pounds instead of 400 lbs. I can now lift the bike onto the center stand by myself! 

I modified the battery tray yesterday to hold the new batteries and am now about to finish the wiring. I hope to have this beast doing a first trial run within the week.
I plan to put a large carrier rack on the back so I can use this to go to the nearby town for groceries. The round trip is only about 4 miles.

This project is most useful to me as a learning experience which will help enormously when I next tackle a proposed electric car project for which I also intend to build my own controller to save $$$. I am in the process of building a large DIY VAWT and expect to be off-grid. With EV's that can run off wind power I won't have to buy gasoline.


----------



## ngrimm (Oct 19, 2007)

You did a great job making it all work together. Should work really well with the lighter batteries. I hope you don't have to use the pedals very often. Congratulations!


----------



## rcavictim (Apr 26, 2009)

ngrimm said:


> You did a great job making it all work together. Should work really well with the lighter batteries. I hope you don't have to use the pedals very often. Congratulations!


Thanx ngrimm! The packaging is pretty well coordinated.

Here is a poor quality picture taken from the rear view. The old seat and handlebars now replaced are shown but the point here is that the full pack of the large grey 105 AH batteries are all installed and you can see how narrow the battery package is. Actually it is so narrow that you can't really see it from the back at all. Catch a glimpse of battery grey just under the black motor sticking out of the right side. The other item of note (yup this is a pun, wait for it!  ), is that 2 foot long chrome air horn placed to look like an exhaust pipe. I figure maybe adding this as a "Hey back off" horn.  I had two of these horns and gave one away but I might be able to get it back. In that case i could have dual chrome 'exhaust' and _really pimp my ride! _


----------



## rcavictim (Apr 26, 2009)

Worked on a steel box today that will go in the rear half of the upper battery shelf under the seat. This will contain the chargers, one per battery, miscellaneous electrical relays, fuses, etc., and the wireless car alarm security system where it will protect the horn/siren module from tampering. An alarm will not be visible at all even with careful scrutiny. This alarm does motion sensing in 10 sensitivity steps plus voltage monitoring. That voltage sense won't be much use the way this thing relies on so many batteries. The alarm will operate off a small 12 volt gell cell battery hidden in the electrical box so that cutting any exposed wires, battery or otherwise will not disable the alarm.

The way I'm doing this up, I could upgrade it quite easily to a real E-motorcycle in the future by simply removing the bicycle pedal drive system, swapping the motor and upgrading the controller. I will now be able to carry seven of the 12 volt 51 AH batteries. That would give me an 84 volt system or 72 vollts and a separate 12 volt battery for lighting, air horns, etc.


----------

