Cool. Smaller power requirements there? I'd be up for similar power and control board. We have a moped to convert. ACIM of course. Hehe.
Connect precharge resistor in series with controller B+ and precharge contactor terminal to precharge capacitors. Battery+ --> precharge contactor --> precharge resistor --> controller B+. When capacitor voltage is high enough you can bypass the resistor. I used switching relay: when 12V was turned on precharge contactor went on. When precharge was done the relay switched precharge contactor off and main contactor on.
I can draw a simple image if you want to. There is also a simple precharging device available from zeva;
Zero Emission Vehicles Australia