Took it for a quick spin round the block and it is all good. Temp cutout works (set it to 60 degrees to confirm cutoff) and the bike pulls really well.
Notes on the motor.
It is quieter than the original prototype, this is likely due to the better balancing on the can and the hall sensors being spaced accurately.
It is getting a little warm and I think I may have the timing a little retarded ( I forgot to note which direction I was spinning the motor when we positioned the halls)
It cools much faster than the prototype.
Note I have not yet connected the water cooling, hopefully a job for next weekend.
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.
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.
Kokam SLPB 255 HR2
3C (or 5C depending spec page)
24 series of 5 parallel cells
2 parallel sets of 20 series cells
Pack Capacity (Max)
Pack Weight (Cells only)
Pack mounting & connectivity
Pack Continuous power
11.5 kw (or 19.2 kw)
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.