I had my first battery recalibration today, and I thought it might me good to post our numbers so we can get an idea of when and how it happens.

Here is the info to post:

FEH: 2008 AWD

Lifetime MPG: 30.0

Mileage at recalibration: 17855

Maximum SOC observed: 82

 

91.2 at 18,300 miles
86.2 SOC at 9600 miles when I had to shut off the engine as I was at work and needed to get into the work location. Restarted the vehicle 8.5 hours later, the SOC declined to 76 SOC then rose to 78 SOC before returning to the normal SOC range.

I have not noticed or seen a third event.

I do not see a correlation between fuel mileage and this event.

 

How about your lifetime average and mileage at the time of recalibration?

 

I now have 89,000 miles and my 2005 has done this a few times.

I estimate it occurs at roughly 10,000 mile intervals, but don't think it is on a "timer" and in my particular case it just detects it needs it every 10k.

YMMV.

The highest mine got was 90.4% SOC on the Scan Gauge.
One time, when the car was at 20,000 miles and I did not have a Scan Gauge, I got 6.5 miles of EV driving on flat ground with lots of stop signs during those 6 miles. So in retrospect, I know that was one case.

 

If everyone posts their lifetime MPG, we can see if there is a correlation. I am wondering if those who use more EV / P&G / "tricks" may be using the battery, and may show different values. I figured that lifetime cumulative MPG would be as good an indicator as any...

 

As far as I can tell I just my fist last week. Hit 80.something, I recall not having regen.My lifetime is around 30. I drive short distances, less than 10mi per trip one way, most are 5-6mi. But country miles, 1 mi+ between stop signs, 45mph speed limit.My FEH is now about 2.5 yrs old, the recal was just short of 26.5k mi.If I had a prior recal, it was when the wife was driving & she didn't tell me it acted any different.

 

I suspect, but don't know for sure, the frequency is related to MDV or Module Delta Voltage. This is something you can detect with a programmed ScanGauge. When all the "little batteries" get out of balance with each other, you may see one of these events. People who drive very little, and/or use very little battery may see recal events MORE often.

Mine almost always sits at 0.06v which is "good".
This is also a measure of overall battery health.
During one Recal, my MDV was 0.12v.

The meter may be programmed to move in 0.06v increments, because those are the only two values I've ever seen.

HTH,
-John

 

what excatly is this? and why is it needed?

my 06 FEH has 121k miles on it. I have owned it since 98k. I have never seen this performed. Please explain in further detail.

 

The internal computers do it automatically.

It checks the health & capacity of the battery and/or conditions it to reduce the "memory" effect, which is slight in these cars, but present.

You don't do a thing.

If you have 121k miles, it has been done a few to a dozen times already. It occurs while driving and is hard to detect.

 

gpsman1 said it pretty well, although we are making educated guesses. We think that as the battery ages, something triggers the car computer to run a test of the battery capacity. It runs the State of Charge (SOC) up to 80 or higher, which is the obvious symptom. Normally the SOC never goes above 60% or so, or below 32. It is believed that this is done so that the computer can adjust what it calibrates as the normal SOC.

I established this thread to see if there is some correlation between how high the SOC goes during this procedure, how often it happens, and the lifetime MPG, which is a measure of how much the battery is used (I am assuming that the higher the MPG, the more the driver is using hybrid hypermiling techniques).