I have two related questions for the technical gurus. 1. Is the Hybrid System Indicator (HSI) Charge (CHG) gauge an ammeter or is it an estimation of current flow back to the traction battery that is based on some other method? I suppose that some of the experts using the Scangauge II may know if the current flow to the traction battery measured using the Scangauge II corresponds with the CHG display. 2. Have regenerated current readings using the Scangauge II (or another method) changed noticeably,under similar speed, grade, and braking conditions, before and after the brake ECU reprogram fix? I watched for a change in HSA CHG characteristics following the brake ECU reflash, although my sense is that the CHG gage does not display sufficient precision to detect a slight and, perhaps evan a moderate, change in regenerated current flow. Thank you
I can try to answer question #1, I would say from watching the HV Amps on the ScanGauge that once the HSI indicator gets over to the regen area (far left) it tracks the Amps to the battery pretty well. I'll take a close look tomorrow and see just how many Amps I can regenerate, I haven't had the fix. The rest of the HSI indication (everything to the right of the regen area) seems to be an indication of power required from both the battery and the ICE. My question, that I've asked in a couple of other topics, is not so much how the amount of regeneration is effected but how controllable it will be with the brake pedal compared to how it is now.
Thank you for the quick answer, tumbleweed. I had the brake ECU reprogram done yesterday and cannot detect any difference in the behavior or controllability of the regeneration. My wife can feel what she describes a little quicker brake response, but I can't. The response of the HSI CHG to gradual braking seems to be the same, to me, after the ECU change, although the analog CHG scale is impossible for me to quantify. BTW; I also noticed that the slight increase in traction battery status (adding a bar or two) and improvement in MPG (a tenth or two) produced by gradual braking, seems to be like it was before the brake ECU reflash. I’m beginning to believe that any hit on regeneration efficiency produced by the brake fix will be minimal.
When I was testing this pothole before and after the fix: I found: Before A0B: entry showed ~75% charge bar, exit showed ~20% After A0B: entry showed ~50% charge bar, exit showed ~50% These are informal observations, without units, but my impression is any regeneration lost on entry is made up on the exit as far as charge rates are concerned. This is just a rough calculation that assumes the ratio of observed regeneration bar is approximately the percentage of kinetic energy recovered: Column 1 Column 2 Column 3 Column 4 Column 5 Column 6 Column 7 Column 8 0 mph km/h KE watts 75% to 25% 50% to 50% 1 20 32 5 544 4 158 2 772 2 19 30 5 004 3 753 2 502 3 18 29 4 491 3 368 2 245 4 17* 27 4 006 3 004 2 003 5 16 26 3 548 887 1 774 6 15 24 3 119 780 1 559 7 14 22 2 717 679 1 358 8 13 21 2 342 586 1 171 9 12 19 1 996 499 998 10 11 18 1 677 419 839 11 10 16 1 386 347 693 12 9 14 1 123 281 561 13 8 13 887 222 444 14 7 11 679 170 340 15 - - - 19 152 19 259 *-threshold speed difference from my testing. Before A0B, there were hundreds of milliseconds when there was no braking force. This is a somewhat flawed model because the regeneration bar is not a ratio of energy capture to kinetic energy. A more accurate model would use the elapsed time to calculate the regeneration energy Whr. However, I suspect the results will be similar. Bob Wilson
Pothole! That's not a pothole; that's a freaking meteor crater! What sort of roads do you have, man? Tom
Thanks Mad-Dog and Bob W. for the information it appears, from initial reports, as if the ECU change has done the job.
LOL! Did I mention the "slip-n-slide" surfaces? Seriously, black ice and a rain-slick Huntsville street ... not a whole lot of difference. Bob Wilson
Someone with a SGII should be able to see if anything has changed. Looking at AMPs and RGO should give you an indication of how much power is going into the battery. Maximum regen available is determined by how much power the battery can take (charge into the battery.) From what other members are seeing, I have a feeling there will be no difference.
All that is happening so fast that I can't imagine anyone picking up on the changes via SGII. If there was someway of logging those values (quick refresh) over time, perhaps you could get a good comparison.
True, it's pretty low-res ..... but regen force actually plateaus at about 15mph to 7mph due to the max .. I have a graph somewhere and I was hitting about 720nm during those speeds... You can see this plateau on the SGII as the number holds steady through those speeds. If the max regen force were affected, you would at least see it. I need to make some more graphs with my laptop, especially for comparison before getting the upgrade.
Although it is not a scientifically valid test, it looks like the 5 day average MPG for my wife's commute is essentially the same as before the brake reflash. She drives about 30 miles per day on a route that is approximately half stop and go and half freeway and has remained consistent at 54 to 55 MPG in the mild S. California temperature.
If some of the xgauges could be turned into passive CAN listens instead of active queries, I bet that would be much faster. But I haven't looked at the latest gen3 table, so for all I know there might be some "old-skool Atilla" style stuff in there. And there might still be some hope for tapping a few wires for an analog approach. . _H*
