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OpenRevolt not turning on power

882 Views 2 Replies 2 Participants Last post by  alvin
Before I start tearing parts out and replacing/resoldering components I'm hoping someone here has a better suggestion for the root cause. The OpenRevolt controller - a "stock" MOSFET version - was working before I stopped driving the little van for the winter.

The only thing that happened over the winter is that I added 5 new cells, so now at 45 LiFe (144 nominal). Voltage reads 148.x V for the whole pack.

The symptom is that although the controller seems to be working correctly there is no power output - no voltage across the motor and the motor doesn't spin.

It appears to be a problem on the 12V side of the isolated 12/12V converter. An obvious conclusion is that that particular component has failed. It does however seem unlikely (but not impossible) that it just quit. More likely there is a problem elsewhere that has either trashed that component or is causing an issue that looks as though that component has quit - drawing too much current might be a good way to do that.

Suspiciously, it looks as though there might be a short between the two grounds. That is, the voltage I get measuring the output of the converter seems about the same as if I measure from the output of the converter to the 12V (chassis) ground - about 30V. Looking, I can see none, but I'm not sure of all the places to look. This could also be a coincidence or be caused by the converter failing.

No smoke, not obviously failed components (that I can see). The processor appears to be working fine - flashes the orange LED then brings in the contactor, sends values out through the serial port, etc.

Anyone have any ideas?


Some more details in case they are useful.

DC/DC still seems to be functioning - headlight/tail lights come on, main contactor clicks in, orange LED on the board comes on, etc.. Measured output is about 12V (11.7?).

Controller Config (unchanged since last running):

Kp=002 Ki=160
throttle_min_raw_counts=0306 throttle_max_raw_counts=0493
throttle_pos_gain=008 throttle_pwm_gain=000
motor_os_threshold=0000 motor_os_ftime=1000
motor_os_dtime=10 pwm_deadzone=05

RTD output when sitting idle:

TR=000 CR=000 CF=004 PW=000 HS=0509 RT=0503 FB=00 BA=000 AH=000.0
(throttle_ref, current_ref,current_fb,PWM output,raw_hs_temp,raw_throttle, fault_bits,battery_amps)

Move the throttle and the throttle raw and reference change as do the PWM and commanded AMPS (but not the actual amps). Still no faults:

TR=248 CR=248 CF=004 PW=510 HS=0509 RT=0402 FB=00 BA=004 AH=000.0
TR=259 CR=259 CF=004 PW=510 HS=0509 RT=0398 FB=00 BA=004 AH=000.0
TR=281 CR=281 CF=004 PW=510 HS=0509 RT=0390 FB=00 BA=004 AH=000.0
TR=284 CR=284 CF=004 PW=510 HS=0509 RT=0389 FB=00 BA=004 AH=000.0
TR=377 CR=377 CF=004 PW=510 HS=0509 RT=0355 FB=00 BA=004 AH=000.0
TR=374 CR=374 CF=004 PW=510 HS=0509 RT=0356 FB=00 BA=004 AH=000.0
TR=352 CR=352 CF=004 PW=510 HS=0509 RT=0364 FB=00 BA=004 AH=000.0
TR=109 CR=109 CF=004 PW=510 HS=0509 RT=0452 FB=00 BA=004 AH=000.0

Temperature (HS) kicks in at 675, so should not be limiting.

PRECHARGE_WAIT (I see this flashing the LED but can't connect fast enough to see the FB)

Will all cause the fault bit to be non-zero so, with some degree of certainty those don't exist.

The OpenRevolt schematic is hard to find on the web - copy attached.


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· Registered
362 Posts
Discussion Starter · #2 ·
Answering my own question...

It really does look to be a failure of the 12V isolated DC/DC. I took a 12V AC ATX power supply and connected it across the isolated output of the 12V and the motor went round.
Could still be a problem with the input, but I doubt it.

Pretty strange. I would expect the MTBF on those parts to be long and I don't think that is suffered any abuse, overvoltage, etc. It wasn't even a particularly cold winter.

Awkward part to replace on the board. I think I'll just add an external isolated DC/DC at least until I next have a reason to pull the controller.

Seems that the output of ATX power supplies are isolated. Depending on whether I believe that, I might be back driving sooner than I thought (is there anyone doesn't have a couple of old PC power supplies lying around?).
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