At a quick glance the controller uses 12 MOSFET’s with 4 per motor phase. This and the various signals from the throttle etc are controlled using a Sinowealth SH79F1611U microcontroller.
I purchased a 36V kit from eBay which includes a 26″ rear wheel with hub motor, motor controller, switched brake levers, throttle and pedal assist sensors.
The battery is a 36V 15Ah unit with a downtube/bottle cage mount.
I found a 1990’s ‘Muddy Fox’ mountain bike to use for the basis of this electric bike conversion. Old steel frames have some advantages over modern aluminium frames when it comes to wedging large motors in them.
The original coilgun circuit used a relay which quickly suffered from contact problems due to the large current flow so I have replaced it with a thyristor.
I’m using a FS2514MH thyristor with an non-repetitive on-state current rating of 330A.
A simple 5V DC battery power supply was built using an L7805 linear voltage regulator and a PP3 9V battery. This certainly isn’t a good way of doing things but I have a large supply of lighly used PP3 batteries so it’s what I’m going with.
SPICE Simulation of 5V regulator.
Later on, during the PCB design, I shall use a buck/boost topology and a more suitable battery.
