Problems with Synkromotive DC 750 Controller

Synkromotive DC750

I have been driving the electric Ghia for 2 years without trouble. Recently, after fully charging, the Synkromotive controller would not activate the main contactor.

It showed an over voltage error. I was charged to 200 volts, however, it read 218 volts which was over its factory programmed upper limit. I tried to reset the factory voltage calibration to fix the problem, however, i could not access the administrator settings and the company is no longer in business. So on to plan B - buy a different controller. I settled on the Soliton JR which i picked up used for $900. It lists for $1,899 at EVwest.

Soliton JR

The main thing I do not like about the Soliton is that it needs liquid cooling to perform properly. The Synkromotive was air cooled. Setting up a liquid cooling kit with radiator and pump adds weight and complexity. It is also bigger and heavier than the Synkromotive. On the plus side, there are more of them out there and it is easier to find replacement parts and get them repaired. The Soliton also does not need an external contactor so I can remove the one that was installed for the Synkromotive.

Netgain Cable Pull Hall Effect Throttle

I had a problem hooking up the Netgain cable pull throttle because I forgot the proper wiring instructions. I couldn't figure out green, white, and blue wires.

I eventually stumbled across the info:


The functions of each wire on the wiring harness are the following:


Orange: 0.8V to 4.45V, signal 1

Blue: ground for signal 1

White: 5V supply for signal 1

Green: 1.6V to 4.95V, signal 2

Black: ground for signal 2

Red: 5V supply for signal 2

Drain wire: grounded



Once I hooked it up properly, I was able to calibrate the throttle and ot worked fine.