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.)
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.
And 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.
Just a quick update. Yesterday I managed to acquire some scrap aluminum plate (recycling some of our company’s old aluminum logo backgrounds) and bought some extra material, bolts and nuts etc. which I’m going to use to install the electronic components inside the bike. And next thursday I’m taking the bike to the welder so that he can weld the attachment tabs for the battery boxes. He should have actual boxes ready by then. Then it’s up to me to drill some holes for ventilation and the cables. And I’m going to paint them black.
I’ve also managed to get a proper length 530 chain and the motor adapter plate is also now installed securely. The reverse protection diode arrived too, so I can finalize the wiring setup. If the rear sprocket finally arrives next week I should have everything I need to finally put everything together and see if we can get the bike moving…
Today I tried the motor into the bike, using 10 and 12mm threaded rods. Still missing some proper 12mm nuts, but got it secured good enough to see how the motor fits. The upper part of the chain clears the swing arm just barely, so with the driver and 35kg of batteries on board it should clear it just okay (fingers crossed). Now I’m waiting for a 49 tooth rear sprocket and a proper length D.I.D 50 roller chain (non o-ring version) so I can try to spin the wheel with the motor. The old chain would have been fine, but it’s too short with the new axle position (gearbox had it closer to swing arm).
I managed to connect the controller to our laptop via USB to serial adapter and got them talking with each other, so that I can now adjust the controller settings. For first test runs I’ve set the maximum power (max output current) to only 30% (135 amps) and made some other adjustments. Also changed the throttle curve to progressive. Feels pretty smooth now (tested on bench).
Today I went to get my motor adapter plate, as it was finally complete. And oh boy, it is awesome. It matches my CAD drawings perfectly and it fits the frame of the bike and the motor itself like a glove. It’s been water jet cut from 8mm 6082-grade aluminum plate. Pretty sturdy piece of metal… Didn’t break the bank, either.
And just to make the day perfect, today I finally tested out the electronics, running the motor without load. My wiring setup seems to work just great, even if it’s still missing the 6A reverse protection diode (ordered but not yet received) from the Alltrax schematics. For the test bench use I’ve set up a motorcycle 12V battery and a switch to “simulate” the motorcycle 12V system. The 12V controls the 72V system with a solid state relay. All the live wires to controller, solenoid and cycle analyst are also fused through the fuse box.
The red key/lever battery cut-off switch is rated for lower voltage systems, but it is not intended to be used as a emergency cutoff. It is there only to switch the batteries off completely after the bike has been shut down (kinda like the fuel valve previously). It’s rated for 500A in short moments so it should handle the currents just fine. I’ve also set up a small indicator led which I intend to install into the final dashboard to indicate the bike has been powered up. (Like you couldn’t notice the speedo and cycle analyst all lit up…)
Cycle Analyst powered up and measuring the power usage.
Just made a quick photoshop concept picture of what the bike should look like after everything is done, just to get a feel… Not too accurate, though. Still wrong speedo, no bar end mirror and some other minor details are not 100% spot on. Yesterday I ordered some fiberglass mat and epoxy resin for the fairing job and received the led turning lights / tail lights. And I also got the proper bolts for the motor as it uses american standards. And I sent the adapter plate cad drawing to the professional doing the manufacturing. Hopefully won’t take long until I can bolt the motor onto the bike.
Lately I’ve been planning the battery boxes (cardboard mockups) and the motor adapter plate, so that I could get them manufactured as soon as possible. It seems that I can fit the batteries pretty tight inside. The larger of the two boxes will be just as wide as the gas tank. While fitting, only some small adjustments came into mind, including beveled edges to the rear corners of the larger battery box, so that the corners won’t hit my knees. By shuffling couple of the cells around it was easy to accomplish.
The whole engine compartment (except the motor) will be hidden behind fiberglass fairings, so the ugly boxes won’t be visible after the bike is finished.