After getting some errors from the controller for my motor, I've been
exchanging e-mail with Azure. They recommended checking the grounds
(all good) and making sure that the cable between the controller and
the motor did not pass too close to the speed sensor or serial
cables. I did all of that and took the car for a test drive this
morning. It seemed a little better, so I decided to make my first
drive on the freeway. I did about 3 miles - guessing that I was doing
65 MPH but I can't be too sure because the speedometer needs to be
calibrated. Since I am still running with a weak 12V battery and no
DC-DC convertor, I got off the freeway and started heading home on
A mile later, the car started hesitating going up a hill and I
smelled something burning. I figured the smell was the transmission
fluid I am leaking, but slowed down and was getting ready to find a
place to stop. The car got even more sluggish. Finally, the power-on
indicator light on the controller went out and I lost all motor
power. Turning off and back on the car wouldn't get the light to come
back on. After a couple of minutes of checking the 12V supply, I
decided to check the high voltage side (the Azure controller will not
turn on without both voltages present). I pretty quickly found the
problem - and a picture is worth a thousand words:
I fried my shunt. It looks like I am back in the garage for a
Better luck to everyone else's projects. I'll let you know what I
On Oct 5, 2008, at 21:28, Randy Pollock <ra...@alumni.caltech.edu>
> From your pictures, the fried shunt looks like it might be the 200-amp
> model (Empro model HA-200-50). This is what came in the Electro-
> Automotive kit I received but it is not the correct part. We all need
> to be using is the 400-amp model (HA-400-50). The voltage across this
> shunt at +200 amps will be +25 mV; just what the ±200 amp meter is
> expecting to see at full current.
Actually, I was one of the first to buy the kit and they sent me a +/- 50
amp gauge and shunt. I swapped out the gauge last weekend, but they
didn't include the correct shunt so I was still running on the old one.
The gauge was way out of calibration - charging at 12 amps (DC) showed
nearly 100 amps on the gauge.
> Let Mike Brown know about this -- he needs to send you the right
They sent a new shunt last night - I'll look at the part number carefully.
> (I wonder if that bolt on the left side might have been a little
> looser than the other one...)
I had the same thought.
Azure thinks the failing connection here might have been explaining some
of the weird data I saw coming out of the controller. We will see when I
replace the shunt...