[Tim Maddux]

I experienced something today that I had long suspected was happening but this was the first time I could confirm it.

Today I reconnected the 12v ground lead after doing a stereo install. The IMA was showing about 3/4 full on the state-of-charge meter when I disconnected the 12v ground. Upon reconnecting, my state of charge meter was at zero, and a force-charge began. After just a couple of minutes the meter leaped to show "full." To me, this means that the Insight computer detected something (voltage? temperature?) that indicated the high existing level of charge in the batteries, stopped force-charging, and updated the display.

I'm calling this a "postive recalibration" in the thread subject to get people's attention, but really it's no different than a regular "recalibration" in that both events are simply adjustments of the state-of-charge meter to more accurately reflect the truth. It's just that we aren't likely to complain/notice as easily when the state of charge meter is fuller than we expected. I think that I have seen this behavior before on the highway and attributed it to my inattention + the "hidden charging" (charging of the batteries without CHRG lights being lit that others have detected with electronic hardware). However, the leaps were too sudden to attribute entirely to a hidden charge.

 

[Armin]

My car was doing this pretty regularly after recals. I called it "upper-end recal".

 

[Insightful Trekker]

Last I heard it was called an BCM reset, IMA reset or simply a reset.

There is the longer approach whereby you disconnect - reconnect certain fuses, and run the engine at 2500 RPM or so to allow sufficient RPM for IMA charging.

But disconnecting the 12v battery effectively does the same thing. Along with loosing the clock and radio presets. And the PCM (engine computer's) learned values.

I'm only posting this so as to try and keep the pre-existing definitions alive.

Sincerely,

 

[Tim Maddux]

I thought perhaps the behavior after 12v disconnect could be extrapolated to ordinary driving, but from what you're saying it could be a unique condition. In other words, after the 12v disconnect the car automatically charges up in search of a "full capacity" indication, and then stops charging and updates state-of-charge readout to reflect "full."

If so, then this isn't an indication that the IMA will update to reflect an unexpectedly high state-of-charge on a regular basis (during normal driving condiitions), which was the conclusion I was attempting to draw.

 

[Insightful Trekker]

I am still having trouble following your train of thought.

Yes the BCM theoretically drifts out of calibration to the "high" side as well as low. How it tends to work in the real world I don't have a clue other than it does drift. Although an incorrectly high SoC gauge makes the most sense as the pack internally self discharges.

The procedure you effectively performed is the same as what was supposed to be done on a routine basis for all Insights at the dealership in stock to keep the IMA pack in peak condition. There is some sort of official procedure maybe even a bulletin on the subject.

As I remember (and as in the past I am hope your sleuthing will correct and expand on it <g>) the IMA pack slowly internally discharges. For hybrids not driven for days or weeks at a time this loss becomes great enough that the car could be in regen on every test drive. Also, long term "storage" of discharged batteries is not the best.

But before I carry on any longer I'd best wait for your clarification especially if I am still missing your point.