Pieces of the Puzzle

During the last weekend I plugged in the isolated DC-DC converter to my test bench and it seems to be doing it’s job, which is supplying 13.5 volts for the 12V system. The 13.5V is a similar voltage as the gas engine’s alternator used to provide and is suitable for charging the battery. The converter is installed parallel with a small 3Ah gel battery that I’m going to use to replace the original large flooded lead acid battery in the bike. The DC-DC will charge the battery and supply the main power to the 12V system. The battery is there just to supply the key-switch power and to share the load in event of energy spikes or when the drivetrain battery voltage is too low and DC-DC decides to turn itself off. I think I’ll eventually install a 12V lithium battery in it’s place, as this tiny gel battery was just a spare I had bought for other purposes. The DC-DC uses the drive system’s 72 volts as the keyswitch current and it shuts itself when the bike is powered down.

Below is the final EV system setup before I dismantled it for the purpose of installing the components to the bike. I’ve now also installed the 6A reverse protection diode between the fuse box (in the middle) and the key switch relay. The DC-DC is the black box in the right bottom corner. I think I will add one more relay for the contactor/solenoid, so that when the on/off kill-switch in the handle bar is turned off the contactor will be shut down, but the lights and everything else in the bike will stay on. (The notification LED will also be moved in parallel with contactor relay, indicating the status of the contactor.)

Complete wiring setup

I also managed to wire the bike’s original electrics back on, so that the headlight, tail light, speedo lighting and turn signals all started working again, using just the battery. And I’ve now pretty much removed all the components related to the gasoline engine, except for some wires and connectors (which shall stay there until some day when I’ll completely rewire the whole bike for this much simpler setup).

Below is my temporary setup before the future reworking of the whole instrument cluster and installing the café style handle bar (will be done only after the registration). The Cycle Analyst is now where I can see it. It will eventually end up to replace the old speedo cluster, combined with the 60mm chrome daytona speedometer. The Magura Twist Throttle has been installed along with a separate on/off kill switch. I still need to figure out how I will mount the CA speed sensor, as the magnet is made for spoked wheels. Jarkko seems to have mounted his into the break disc holes of his kWsaki, but mine has no such holes to mount it into. But maybe I’ll figure out something… We shall see.


eHonda51And here’s the motor installed in place. Feels pretty sturdy, even without the third mounting point, which will be supported to the battery boxes. I think the current mounting points are already enough to support the motor, but the third point is there just to provide additional stability. From the looks of it, this motor seems like a perfect fit for this frame. The right side is in perfect line with the body and nothing sticks out. And with the threaded bolt setup, I can fine tune the exact chain alignment with just a couple of bolts. What I have also done is that I have removed the old battery rack and have started figuring out how I will mount the electronics onboard. I think at first I will mount most of them where the old battery used to be, between the fiberglass side panels, below the seat. There they will be pretty well protected from the rain and dirt. As I examined the gas tank (now empty), I think that by cutting it’s bottom I can eventually fit most of the electronics inside the tank. But that will wait (just a precaution) until I’ve successfully registered the bike as an electric motorcycle. That would actually be the first and only thing I’ve had to cut, as I’ve managed to do the entire conversion so far without any modifications to original components. And I’m a bit hesitant to do anything like that until this conversion has been proven rock solid.

Motor mounted


2 thoughts on “Pieces of the Puzzle

  1. You are right about that. Can’t beat the feeling of doing things yourself and seeing it work. This thursday I’m having the battery boxes fitted and I’m also taking the whole friday off, so that I can focus on putting the bike together and having everything mounted up in the bike. If the new rear sprocket arrives this week (it should) and I can get the new chain installed, it could be that this thing will be ready for a test spin…

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