Du to the new batteries that have a very rectangular shape it is going to be hard to fit them in the bike. I have been working on some mockups with a friend and it looks like we should be able to fit them in… with a little effort.
The packs have alloy pressure plates with ABS between the alloy and the cells. In these images the batteries are replaced by 12mm ply (the thickness of two cells).
Here I have the larger pack (at the bottom) and the smaller pack in the approx location we are planning.
It is going to take quite a bit to mount this up properly and have room for all the other stuff required.
A quick summary of the project so far
Back in 2010 I acquired a 1985 Suzuki RG250 for the conversion. I spent the next 3 years selecting and buying parts, rebuilding the rolling chassis and assembling all the parts into a working and registered bike.
Things I have learnt
The hardest part of the bike conversion is building, configuring and managing the battery setup. Limited space on the bike and the “shape” of that space makes constructing and mounting the battery pack very difficult. With this in mind I used Headway cylindrical cells allowing me to create quite an organic shape. However the construction method has meant I have never been able to get the pack running perfectly. The motor and controller is not difficult to mount, configure or use, even when using a prototype motor.
Things that have changed
Battery technology has marched forward at a great rate. Chemistries and brands that were impossible for individuals to acquire are now available via either spare parts for electric bikes and cars or via near new condition as large companies have left over batteries from research and development projects. One large example of this is the liquidation of stock from the BetterPlace company.
The little components to build an electric vehicle project have cheaper, more available and a larger range of options. New lighter contactors, fuses, DC/DC convertors and battery management systems.
Changes included in the rebuilding
I have been lucky enough to get onto a purchase of some extremely good prismatic batteries. These Kokam batteries are like large foil pouches which have the layers of cathodes, anodes and electrolyte sealed inside. They are large rectangular and quite flat and unlike my current Headway batteries they have no real structural integrity of their own. These batteries also run at a higher nominal voltage (3.7 rather than 3.2) and each cell is 31ah rather than 10ah. This means my new pack will have 40 cells compared to the 120 cells I now have to run. In turn this means a more reliable, easier to manage pack overall. These batteries are also capable of delivering significantly more power than my existing setup.
New BMS (Battery Management System)
Along with the new batteries I am also updating the way I manage the batteries in the pack. Zeva (www.zeva.com.au) have released a new set of boards and control units for battery management. They are small, light and fully featured making them ideal for use on a motorcycle. Four boards, a central core and a display unit will be able to monitor each cell individually and protect the cells during charging and discharging. Along with the core the setup lets me drive the standard fuel gauge as a state of charge meter, the tacho as an instantaneous amp meter and the temp display will display motor temp (with an additional temp sensor in the motor).
Updated 12 volt setup
At a minimum I will be redoing the 12 volt wiring loom to work with the new BMS and the new component layouts. I am also looking at wiring up a RFID or wireless setup for “startup” and charging. To this end I am very tempted to buy the MotoGadget m-Unit device to replace my fusebox, flasher relay and headlight relay. It also has a RFID accessory to support the keyless startup.
Sorry it has been a while but I have been working hard on getting the bike up and running again.
I wanted to use the newer designed motor as a replacement, mainly to test the motor for the guys that designed it, but also to quieten some loud critics of these motors.
So got a new motor mount made
Running the new motor however seemed quite difficult and hard to get smooth running from it. I pulled the hall sensor board out and found that they were mounted backwards and at an angle, the best they could do is pick up the magnetic flux from the coils. No wonder the behaviour was so bad.
So I created a replacement board and lined up the hall sensors as accurately as I could.
The motor now runs quite well with all things working almost as good as the original.
I have also taken this opportunity to replace my Battery Monitoring System with a Battery Management System from zeva.com.au
All in all I should be back on the road in a couple of weeks.
Ok so today on the way home I noticed the bike starting to make a strange “rough” sound. I backed off the throttle and got about 3 to 4 times the “regen” that I normally do. Once stopped the familiar smell of electrical burning and a small cloud of smoke wafted by.
So while saying a few choice words I pulled over and turned off the bike. Getting off I could see no new smoke and the motor was warm to the touch but not hot.
I pushed the bike about 10 meters all the way noticing that the motor was resisting the movement as if I had shorted the phase leads.
Now I know it could be motor or controller at this point, so I call the cavalry (my wife) and she came and got me with the trailer. I had to remove the chain so I could push the bike up the ramp.
I have just finished disconnecting the phase leads and pulling the motor out. The motor still resists turning so I am pretty sure the phases are shorted. Tomorrow I will pull off the casing of the motor, measure some resistances and try and find the short.
Looks like a might have to rewind the motor or replace it.
I entered my motorcycle into the Bombala Bikeshow‘s “Most Unique” category to see how it would go and, well, I won.
I arrived with the bike at around 11 am and rode the bike onto the show paddock. My wife said it was the most amusing thing to watch the heads snap around to see what was going by. I spent the following 5 hours talking to everyone and anyone about the bike and to be honest 99% of the people thought it was great and could understand why I had done the conversion.
By the end of the day I had several people calling me “Mr Electric”, well worth the 5 hours of driving and sunburn.
Here is me accepting the award from Bombala’s Mayor.
The bike in the winners circle.
So with the bike together and registered and a range of over 35km (even with some bad cells in the pack) I decided to try some trips to work. First trip was on the weekend with a support, vehicle just in case, and that went well.
This week is fine and clear so Tuesday I bit the bullet and rode in with all the other traffic. I made it home with capacity to spare and only used about 2.4 kwh of electricity for the 36 km I traveled. Today (Wednesday) I rode again via a slightly different route and at a slightly higher average speed. 2.29 kwh for the 34km. That means I use about 42 cents of electricity on average for my daily commute, compared to $3.70 of petrol in my 650cc motorcycle. Not to shabby.