Low voltage from open revolt precharge - Fuel Economy, Hypermiling, EcoModding News and Forum

RobW · 05-17-2013, 08:06 AM

Hello all, I need some expert help here with my open revolt controller. The precharge wire from my controller is only showing 9.5 volts, not enough to close the main contactor. I have set the programming to 5 seconds using RTD explorer. Any ideas as to why the voltage is not coming up to a full 12v? Precharge from the battery pack is at full charge. I'm using a 72v system.

I just did a followup test: I set the precharge back to "000", then turned off the system, then back on, and the precharge yellow wire is still showing 9.5v. Shouldn't it be "0" with the precharge at "000"?

RobW · 05-27-2013, 07:23 PM

Ok tech guru's I have been looking at the wiring/board diagrams for the open revolt trying to figure out why the pre charge thingy isn't working. I wanted to include a picture but can't seem to get it sized right. So I am going to try to describe my question.

On the controller board where the p-channel mosfet (Q1) is, I see that 12v is on the outer side of Q1. On the board diagram there is an indication that this 12v is also routed through the board to a resistor "R5" Via Q1. Does that sound right? If so, then when I check conductivity through from the outer pin of Q1 (p-channel mosfet) to the resistor, I get no indication of connection. Also when I check power from the outer pin of Q1 with power on, I get 12v, but when I check the outer side of R5, I get "0". So if I am looking at the diagram right, shouldn't there be 12v between the outer pin of Q1 and R5? If I am right here doesn't that mean that there is a problem on the circuit board?