Project Aims

  • <$10,000 conversion
  • Top speed of +100kph
  • Range of +100km
  • Make a bike that is able to be registered
  • Make the bike look like the standard petrol version

Design Specification

  • Regenerative braking
  • 1990 Suzuki Across
  • 216VDC @ 15A (~3.2kw) VRLA battery pack (~90kg) for proof of concept
  • 3.3kw 3 phase induction motor

Thursday, December 4, 2008

Indicators, Grips and the Motor

I have been getting quite motivated lately to get some work done on the bike. I have just received some led blinkers. I have ordered the 0-5v hall effect twist grip throttle that should be arriving tomorrow. I have done some more research on Mosfets and IGBT's for the motor controller. At the moment I am leaning toward a 600V IGBT. I am switching 360V which is a little on the high side for mosfets, and there are some quite quick IGBT's. I am about to start the schematic for the motor controller.
The good news is that I have finally cracked open my 3kw 3 phase induction motor and had a peak at modifying the wiring to half the voltage I need to drive the motor with. I started by cutting the tape holding the wiring together and numbering each slot. The motor is a 4 pole motor with 36 slots. This gives me 12 slots per phase,and each slot is paired to make 6 coils per phase. There are the 6 wires coming into the motor and 9 wires that jump between coils. After writing all this down I then had to work out what it meant and what I have to cut to take the 6 in-series coils in half to get 2 3 in-series coils and run them in parrallel to get half the voltage. I figured out that each phase has 3 slots next to each other and then the next phase has 3, then the next and so on. This give me 4 sets of 3 slots per phase which is where the 4 pole comes from. So I have found the 3 wires I need to cut to halve the voltage. Yay!!!

Monday, November 24, 2008

Update On Battery Pack

After a long break I am looking at getting back into the bike conversion (been very busy with work and family). I am itching for a ride everytime I see the dust covered Across. I have re-evaluated the battery pack and after seeing some other conversions and considering the cost of the lithium batteries. I am now looking at a 336VDC @ 7AH battery pack. This will be either gel or SLA for cost purposes to begin with and then upgraded to a lighter and higher powered lithium pack if all goes well.
Running the battery pack at this voltage will allow for a simpler 3-phase motor controller since I won't have to increase the voltage. I can simply use PWM to lower the voltage and frequency to the required levels. The motor will be run in delta configuration which requires 230V AC and then re-connect each of the windings so that I run them in parallel not series so this will end up requiring ~120VAC which is about 340Vp-p and within the battery pack voltage.