What This a Recalibration Event?
#31
10-12-2011, 09:16 AM
Hybrid and Ethanol Expert
Join Date: Mar 2005
Location: All over the Central U.S.
Posts: 3,616
Re: What This a Recalibration Event?
To addre ss the original post, I've driven in EV with with scangauge showing upper 30% a few times. I did not correlate it to any specific event, just assumed it was a fluke.
I have seen about half a dozen positive recals, where the computer does a super charge up. I have one time seen a negative recal where the car went down to I forget... but I think 18% and then right back up.
All hybrids do this, and while I don't have all the answers, I am fairly certain you car is behaving normally as I see this with less dramatic symptoms from time to time.
John
I have seen about half a dozen positive recals, where the computer does a super charge up. I have one time seen a negative recal where the car went down to I forget... but I think 18% and then right back up.
All hybrids do this, and while I don't have all the answers, I am fairly certain you car is behaving normally as I see this with less dramatic symptoms from time to time.
John
#32
10-12-2011, 11:41 AM
Re: What This a Recalibration Event?
Sorry, you may have a good idea about how the computer works, but you don't understand how sensors work. The temp sensor has a very linear resistance characteristic versus temp. Measure the resistance and you know the temp... actually a very simple concept.
On the battery state of charge, I believe Ford selected the range of the charge/discharge for the NiMH battery for a couple of reasons. One is that the state of charge is very linear relative to voltage. Thus if you know the terminal voltage, you know the state of charge. Again, a simple concept.
On the battery state of charge, I believe Ford selected the range of the charge/discharge for the NiMH battery for a couple of reasons. One is that the state of charge is very linear relative to voltage. Thus if you know the terminal voltage, you know the state of charge. Again, a simple concept.
On the other hand, in the range that the SOC normally stays, there is essentially no relationship between SOC and voltage. The FEH looks at the juice in and out and tries to figure out the SOC from that. The recal thing just moves into a region where there is a relationship between SOC and V and then it goes back to counting current in and out. There are all kinds of papers on ways to determine SOC for NiMH batteries but just looking at voltage and temp isn't one of them. What I read is that Ford chose to keep the SOC in the middle so the batteries would last longer.
#34
10-12-2011, 04:12 PM
Re: What This a Recalibration Event?
The graphs I've seen show linearity. Please post your graphs and name their source.
#35
10-12-2011, 05:11 PM
Re: What This a Recalibration Event?
The scangauge gets data off a CAN bus... a communications path. Think of ethernet, only different protocol. You can define priorities to devices attached to the CAN bus. The scangauge is a low priority device. It gets it's needs taken care of last. You may think it is just tuning in to what is there, like tapping a phone line... or listening to the radio. This is not how it works. The scangaug must "ask" for each piece of data, and the device on the other end must respond. There are several devices or modules that can respond, if the scagauge knows who to ask. It is a two way conversation and that takes up bandwidth, and the scangauge is asking the questions say, once per second, and multiple questions at that. If the bus is busy, the scangauge is ignored.
Mine get corrupt or incomplete data sometimes ( water temp -40F ) and sometimes a value gets "stuck" or frozen from time to time for a few seconds. I'm not saying this is exactly what you saw, just don't put too much trust in the number.
The FEH can charge about 1% every 30 seconds... best case, if you were parked and not driving. How long did it take to ge back to normal of 53%? 49% should have taken the car about 25 minutes to recover from. Longer if you were driving at the time.
If it went quicker, the number you saw was corrupt, not the battery.
As for resistors or thermocouples they drift over time as they age and can be affected by shock, vibration, and extreeme temperatures that permanently change their properties.
Not so linear either. Linear in the range you are interested in, perhaps
Mine get corrupt or incomplete data sometimes ( water temp -40F ) and sometimes a value gets "stuck" or frozen from time to time for a few seconds. I'm not saying this is exactly what you saw, just don't put too much trust in the number.
The FEH can charge about 1% every 30 seconds... best case, if you were parked and not driving. How long did it take to ge back to normal of 53%? 49% should have taken the car about 25 minutes to recover from. Longer if you were driving at the time.
If it went quicker, the number you saw was corrupt, not the battery.
As for resistors or thermocouples they drift over time as they age and can be affected by shock, vibration, and extreeme temperatures that permanently change their properties.
Not so linear either. Linear in the range you are interested in, perhaps
#36
10-12-2011, 06:08 PM
Re: What This a Recalibration Event?
I have no question that the HV battery was drained overnight, but it had nothing to do with a recalibration IMO. The information provided of reverse gear problems matched my experience with a low SoC. I drive my FEH's to the MAX, everyday and get more out of them than anyone that has ever posted on the subject.
There are two people I highly respect regarding the SGII, and that is the inventor, Ron Delong and an Electrical Engineer and owner of a '05 FEH named CarlD, who no longer post on GH. Ron doesn't post, but you can ask questions of CarlD on http://www.cleanmpg.com/ I brought Ron and Carl together in 2007 to develop SoC on the SGII for the FEH, and now many other X-Gauges you see today from Carl and on Ron's website.
It's funny, the SGII is brought to you by a company called Linear-Logic
Ron has told me that glitches can occur like John has claimed, and I've seen them myself. I don't think this was a computer glitch unless it happens over and over. I've seen this in my '09 FEH which the average tank MPG is 125mph! The SGII is still a great tool and I recommend it everyday.
GaryG
There are two people I highly respect regarding the SGII, and that is the inventor, Ron Delong and an Electrical Engineer and owner of a '05 FEH named CarlD, who no longer post on GH. Ron doesn't post, but you can ask questions of CarlD on http://www.cleanmpg.com/ I brought Ron and Carl together in 2007 to develop SoC on the SGII for the FEH, and now many other X-Gauges you see today from Carl and on Ron's website.
It's funny, the SGII is brought to you by a company called Linear-Logic
Ron has told me that glitches can occur like John has claimed, and I've seen them myself. I don't think this was a computer glitch unless it happens over and over. I've seen this in my '09 FEH which the average tank MPG is 125mph! The SGII is still a great tool and I recommend it everyday.
GaryG
Last edited by GaryG; 10-12-2011 at 06:13 PM.
#37
10-12-2011, 07:20 PM
Hybrid and Ethanol Expert
Join Date: Mar 2005
Location: All over the Central U.S.
Posts: 3,616
Re: What This a Recalibration Event?
The glitches are not a flaw of the scangauge, or the FEH... just a fact of life when a lot of data is involved.
As an example just today in mine. The navi radio has automatic volume control if you select it. It will make the radio louder the faster you go to compensate for road and wind noise. It can be turned off, and has eight levels of magnitude. I set mine to 3 out of 8 years ago and kind of forgot it was there. I was reminded today.
The radio uses the CAN bus to ask the FEH what the speed is, just like the scangauge.
Well, I was at a stoplight, and for 3 seconds the radio got really loud, then went back to normal. The radio got a false reading of some really high speed, maybe like GaryG's 125 mph, but then got the correct info (0 mph) next time it asked.
This is not a theory, I know for sure this how the radio works.
I also know for sure the CAN bus is not perfect.
John
As an example just today in mine. The navi radio has automatic volume control if you select it. It will make the radio louder the faster you go to compensate for road and wind noise. It can be turned off, and has eight levels of magnitude. I set mine to 3 out of 8 years ago and kind of forgot it was there. I was reminded today.
The radio uses the CAN bus to ask the FEH what the speed is, just like the scangauge.
Well, I was at a stoplight, and for 3 seconds the radio got really loud, then went back to normal. The radio got a false reading of some really high speed, maybe like GaryG's 125 mph, but then got the correct info (0 mph) next time it asked.
This is not a theory, I know for sure this how the radio works.
I also know for sure the CAN bus is not perfect.
John
#38
10-12-2011, 07:28 PM
Re: What This a Recalibration Event?
Sorry my friend, an RTD (Resistance Temperature Detector) does not drift. You're wrong.
The resistance versus temperature characteristic is a physical property of the metal used. In high accuracy applications they use a platinum element which turns out to have a very linear response.
I'm sure in cars they don't use such an expensive element. Whether it is precisely linear or a curve or whatever, doesn't make any difference. So long as they can characterize the "curve" and program it they can use it.
These things don't drift. They don't change because of shock. They don't change because of high temps. They don't age out. It's just a piece of metal with a known characteristic that can be programmed.
Of course corrosion can creep in to the connectors & other parts of the wiring connecting it to the computer.
The remark on no water element is right. Water temps are interpolated from Cylinder Head Temps.
The resistance versus temperature characteristic is a physical property of the metal used. In high accuracy applications they use a platinum element which turns out to have a very linear response.
I'm sure in cars they don't use such an expensive element. Whether it is precisely linear or a curve or whatever, doesn't make any difference. So long as they can characterize the "curve" and program it they can use it.
These things don't drift. They don't change because of shock. They don't change because of high temps. They don't age out. It's just a piece of metal with a known characteristic that can be programmed.
Of course corrosion can creep in to the connectors & other parts of the wiring connecting it to the computer.
The remark on no water element is right. Water temps are interpolated from Cylinder Head Temps.
#39
10-12-2011, 07:48 PM
Hybrid and Ethanol Expert
Join Date: Mar 2005
Location: All over the Central U.S.
Posts: 3,616
Re: What This a Recalibration Event?
To troubleshoot instruments, it has a lookup table.
It has a list of expected values. If ohms are x, temperature should be y.
Maybe GaryG can look that up. I dont have my copy handy.
As for battery recalibration, it has the following conditions:
Rebalance mode
Reset SOC mode
Reactivation mode
Refresh mode
Normal End
Abnormal End
Suspend
Unable to start temp is out of range
#40
10-12-2011, 09:28 PM
Re: What This a Recalibration Event?
The FEH can charge about 1% every 30 seconds... best case, if you were parked and not driving. How long did it take to ge back to normal of 53%? 49% should have taken the car about 25 minutes to recover from. Longer if you were driving at the time.
If it went quicker, the number you saw was corrupt, not the battery.
If it went quicker, the number you saw was corrupt, not the battery.
Man you guys have been busy on this subject. In response to the above question, I drove the car on a short drive through town (about 10 minutes out and ten minutes back) and the battery was still not back to normal operating range (53% SOC) when I returned. I wish I had paid closer attention to exactly what the reading was. I just remember looking at it when I parked in my garage and noticed that it had recovered, but not completely.
