Electric Ninja

Quick post for today so I can get back to studying for final exams.

Since nothing on the stock wiring harness worked when the donor bike was purchased, I assumed getting the headlight, brake lights and blinkers functioning properly would be more than a weekend long process. However, after spending several hours diagnosing problems, varying from poor switch connections and splice jobs to corroded copper wire, every single light on the bike ended up working flawlessly.

I had to rewire the headlight 10 amp through the unused 10 amp ignition fuse because some of the old relays in the fuse box weren't useable after removing the starter switches.

Lights!:

Because I wanted to lower the center of mass on the bike and remake the busbars on the batteries with thicker copper sheets, I am now using fewer batteries and a 28 series 4 parallel battery orientation. At first I wasn't sure what to do with the newly opened space on the top battery pack. It just so happens that for the past few weeks I had been considering purchasing a Manzanita Micro PFC-20 9000 Watt charger to communicate with the Manzanita Micro battery management boards. The charger can turn down the output battery side power when the boards start to shunt. Even better, the charger would allow for more than half the charge time from my old charger, and it fits perfectly in the newly opened battery area. I am graduating next week and it sounded like the perfect graduation present to me. Weird huh? You thought your 1000 watt PC power supply was powerful? Try over 9000 Watts.

Manzanita Micro PFC-20:

As of last weekend, the bike is running.

After countless trips to Lowes and Napa, I picked up all the stainless steel bolting hardware and fine grit sandpaper needed for a solid connection between the high voltage hardware. I also made a new ground on the bike and installed a temporary switch to turn on and off the controller without activating the 96 volt battery pack. The ignition key is then used to power up the main contactor after the controller is running.

There are some really intuitive custom gauges on the Synkromotive controller user interface which I set to monitor motor and battery current for the moment. The computer with the user interface installed can even store data logging from the controller. Overall I'm very happy with the controller and more than satisfied there are no issues with external contactor precharge circuitry.

The laptop communicates with the controller through a LAN to USB adapter:

My handmade busbar connecting the main contactor and positive battery controller terminal:

There is still a bit of tweaking expected and low voltage lighting wiring needed for a rideable status. 

This weekend has been unparalleled as far as build progression goes. I would go so far to say there has been more physical headway on the bike than an average entire school quarter in the past two years. The single motor is now completely bolted and wired into the sub frame, and the controller is zip-tied down for now on the freshly cut electronics mounting plate. Even the high voltage motor cables are in place and each cable's respective nut and bolt are just waiting to be torqued down, giving me hope the bike will be running next some time next weekend.

Originally, I had the controller mounted perpendicular to the bike. Only when really understanding how the controller was meant to be wired up and where the battery terminals were located, aligning the controller parallel to the bike started to make much more sense. After the redesign, and making a mockup of the four Manzanita Micro battery management boards, I realized I could shift the controller over on the top electronics mounting plate, and mount the boards in the newly opened area. Doing so eliminated the need to attach a second plate to the back of the main battery pack and also protected the battery management boards by placing them in a better enclosed location.

Controller and BMS boards in place:

On Sunday I ran to Westbay Autoparts and found the 3/16 inch key stock needed to lock the fifteen tooth sprocket in place on the motor shaft. Cutting it was easy with a dremel tool. However, mounting the motor in place was another story because of a few unexpected issues involving the aluminum mounting plates. After some deliberation, I found a solution by allowing the motor to rest on some rubber gasket material. This should relieve the moment on the front mounting plate as well as prevent any steel on aluminum interaction.

Because the main outcome of this bike has always been to learn before having a finished product, I have never been afraid to do significant redesigns. This fact alone has allowed the project to provide me with the best engineering learning experience during my time at the University of Washington.

The first motor is finally bolted in and wired up:

A government website explained for the lowest conductivity, and best connection between copper and tinned copper  NO-OX-ID should be used. It's not zinc based like its cousin Noalox and prevents corrosion without adding metals that reduce conductivity. On the matter of crimping or soldering lugs, there seems to be little consesus on which method produces the best connection. A good crimp however does maintain a copper to copper connection which will have a lower conductivity than any penetrating lead solder. The tinned copper lugs from spectrowireandcable.com are dirt cheap and worked great on the 1/0 cable.

Crimping the 1/0 lugs:

My goal is to have the bike running by March 16th. Of course there will still be many months spent afterwards tweaking the user interface and refining the bike. This goal means setting aside a few design issues, like rebuilding the battery packs with thicker copper bus bars and finding a way to slightly reduce the size of the lower battery pack to fit inside stock fairings.

Other more pressing issues come to mind like bolting the motors into the frame without creating any large stress concentrations. Welding the aluminum created slight warping in the mount so I'm considering using a rubber damping material to distribute the load more effectively. I also would like to have better access to the motor terminals since there is little clearance in the mounting frame. This should be easily solved by trimming back the large aluminum mounting plates slightly. Luckily, doing so will have no effect on structural integrity, it will only take more time.

Honestly, until last summer the blog has been somewhat of a joke, and more of a log for myself than anything else. I realize I've done a terrible job both maintaining and updating it, so I'm going to make it a point to post quality updates regularly from now on. In light of this, here are some pictures taken back in August and Spring of 2010 of the motors in the bike frame.

Downtube attachments:

Side view of the bike taken at Manzanita Micro in Kingston (Notice the freshly painted rims and new tires!):

Quite a few parts for the bike are scheduled to arrive this weekend including some double walled color coded glue infused heat shrink, 700 amp fuses, and heavy duty tinned copper lugs. I also ordered a smaller bore sprocket to fit on the single motor shaft so I can get the bike running with one motor just for now.

The Agenda for this quarter:

-Bolt in motors and set chain to the proper length

-Lay out components where they will be bolted into place

-Cut cable to length

-Crimp lugs making sure to bend the cable as they will be installed

-Heatshrink lugs

-Bolt on finished cable

-Complete low voltage wiring

-Start the bike!