Here's some info about this question I brought up a while back. Feel free to ignore it and continue with the discharging set-up line of inquiry.
Originally Posted by eq1
Does anybody know, off the top of your head, what the imbalanced thresholds are? For example, perhaps the BCM or whatever needs to have all sticks, or all voltage taps at least, within 5%, 10%, 20% of each other in terms of voltage, voltage under load, maybe IR calculations, etc., before it will trigger a trouble code (1447 I think it is)?
This is one type of imbalance, that causes a 1449-74 code, called "Battery Module Individual Voltage Input Deviation," from the advanced troubleshooting pdfs accessed at one of the stickies atop one of these forums. Under certain conditions, if "the voltage difference between channels [voltage taps] is 1.2V or more for at least 25.4 seconds," the car will throw the 1449-74 error code...
Not sure if this is the way to explain it, but I think the primary 'enabling' conditions, that is, the conditions under which this diagnostic are valid, are these:
-The voltage tap voltage needs to be at least 14.5V
-The temperatures at the 4 thermistors need to be at least 77F
-Assist or discharge current needs to be between -20A and +11A
It looks like this is monitored continuously, that is, whenever these conditions are being met, the car is monitoring for the possibility to throw this code...
Here's the general description:
"The voltage difference between channels (12 cells/channel) is 0.61 V at the maximum within the allowable capacity range (15%). However, if one cell in a channel is abnormal, the voltage difference is 1.2V. Also, the voltage detection tolerance for the BCM (battery condition monitor) module is specified as ±0.12V at 32-140° F (0-60°C). Therefore, if the difference between channels is 1.2V or more, at least one cell is considered abnormal. If there is an offset problem or a gain problem in the voltage detection system, and the voltage detection error is out of the tolerance specified, a malfunction is detected and a DTC is stored."
Thought I'd include this here, too, for 1449-78. Do we know what the "upper and lower limits of the SOC voltage" are? Are these the 192V at the top and the 120V at the bottom, or perhaps voltage tap voltages?