Regen Braking
#41
01-13-2009, 08:56 AM
Re: Regen Braking
Sorry to go further of topic here but...
The problem with using the "ignore" feature is that when new users come to this site looking for answers and reading through these post, they will still see Willard's distractions. Allowing Willard to distract the threads and spread FUD is a disservice to this site and its users. We, as regular positive contributors to the FEH/MMH/MTH portion of this site, have politely asked Willard to leave. That should be enough. If he continues and people are reporting him as abusive then what else is there to be done to make sure that owners and potential owners get the best information they can from this site?
It's people like Willard that will bring this site down.
The problem with using the "ignore" feature is that when new users come to this site looking for answers and reading through these post, they will still see Willard's distractions. Allowing Willard to distract the threads and spread FUD is a disservice to this site and its users. We, as regular positive contributors to the FEH/MMH/MTH portion of this site, have politely asked Willard to leave. That should be enough. If he continues and people are reporting him as abusive then what else is there to be done to make sure that owners and potential owners get the best information they can from this site?
It's people like Willard that will bring this site down.
#43
01-13-2009, 09:29 AM
Re: Regen Braking
Thank you so much for this information. I had no idea I could do this and highly encourage all to ignore wwest. He has no intention of doing anything other than discredit the FEH/MMH which he freely admits he does not own. He has stated his son drives a FE but it is not a FEH therefore irrelevent. I now can read in peace without having to subject myself to the idiotic postings of a person who is obviously killing time between naps by irritating others.
#44
01-13-2009, 10:20 AM
Re: Regen Braking
I am now also enlightened about the "ignore list" option and have exercised it to ignore wwest.
#45
01-14-2009, 04:48 PM
Hybrid and Ethanol Expert
Join Date: Mar 2005
Location: All over the Central U.S.
Posts: 3,616
Re: Regen Braking
Regen is typically, only about two-thirds as strong as assist ( amperage wise ). I'd like to explore why that is in this car, as I have read that NiMH in general can recharge as fast as they can discharge. One attribute that is better than LiION, which in general, take 2 times as long to recharge as discharge.
The peak assist can be close to 100 amps.
The peak charging is closer to 65 amps.
It rarely gets to these limits.
This is how the car is programmed, and it may simply be a longevity issue.
( gentler use = longer life )
The peak assist can be close to 100 amps.
The peak charging is closer to 65 amps.
It rarely gets to these limits.
This is how the car is programmed, and it may simply be a longevity issue.
( gentler use = longer life )
#46
01-14-2009, 05:31 PM
Ridiculously Active Enthusiast
Join Date: Sep 2006
Location: Beautiful Pacific NW
Posts: 1,678
Re: Regen Braking
Regen is typically, only about two-thirds as strong as assist ( amperage wise ). I'd like to explore why that is in this car, as I have read that NiMH in general can recharge as fast as they can discharge. One attribute that is better than LiION, which in general, take 2 times as long to recharge as discharge.
The peak assist can be close to 100 amps.
The peak charging is closer to 65 amps.
It rarely gets to these limits.
This is how the car is programmed, and it may simply be a longevity issue.
( gentler use = longer life )
The peak assist can be close to 100 amps.
The peak charging is closer to 65 amps.
It rarely gets to these limits.
This is how the car is programmed, and it may simply be a longevity issue.
( gentler use = longer life )
#47
01-15-2009, 09:55 AM
Re: Regen Braking
Regen is typically, only about two-thirds as strong as assist ( amperage wise ). I'd like to explore why that is in this car, as I have read that NiMH in general can recharge as fast as they can discharge. One attribute that is better than LiION, which in general, take 2 times as long to recharge as discharge.
The peak assist can be close to 100 amps.
The peak charging is closer to 65 amps.
It rarely gets to these limits.
This is how the car is programmed, and it may simply be a longevity issue.
( gentler use = longer life )
The peak assist can be close to 100 amps.
The peak charging is closer to 65 amps.
It rarely gets to these limits.
This is how the car is programmed, and it may simply be a longevity issue.
( gentler use = longer life )
#48
01-15-2009, 11:56 AM
Ridiculously Active Enthusiast
Join Date: Sep 2006
Location: Beautiful Pacific NW
Posts: 1,678
Re: Regen Braking
The difference in charge/discharge limits is due mostly to the pack's high internal resistance. For a typical HV battery temp, you might have a charge limit of 22kW and a discharge limit of 29kW. When charging at high current the terminal voltage approaches 380V, while when discharging high current the HV terminal voltage will be 300V or less. High charging currents would require
voltages too high for the motor/generators.
I rather doubt that you meant to say motor/generators, more likely the solid state controls thereof. Since the Prius HSD system has been doubling the base battery voltage for a number of years now to get more efficient MG operation I even rather doubt that the FEH/MMH solid state electronic components are at risk for failure from "higher" voltages.
VVCs and lower internal resistance cells ameliorate this effect, which the upcoming FFH is supposed to incorporate.
voltages too high for the motor/generators.
I rather doubt that you meant to say motor/generators, more likely the solid state controls thereof. Since the Prius HSD system has been doubling the base battery voltage for a number of years now to get more efficient MG operation I even rather doubt that the FEH/MMH solid state electronic components are at risk for failure from "higher" voltages.
VVCs and lower internal resistance cells ameliorate this effect, which the upcoming FFH is supposed to incorporate.
The regen voltage waveform, on the other hand will be traditional sine waves and therefore only capable of battery recharge at or near PEAK voltage, rectified, of course.
#49
01-15-2009, 12:12 PM
Ridiculously Active Enthusiast
Join Date: Sep 2006
Location: Beautiful Pacific NW
Posts: 1,678
Re: Regen Braking
In regards to regen braking, here are some clinical data, obtained from my own vehicle, using aftermarket testing devices:
Regen brake amperage at 75 degrees OAT, and 72 degrees battery = 50.0A
Regen brake amperage at 60 degrees OAT, and 75 degrees battery = 52.0A
Regen brake amperage at 44 degrees OAT, and 72 degrees battery = 50.0A
Regen brake amperage at 33 degrees OAT, and 69 degrees battery = 49.0A
Regen brake amperage at 23 degrees OAT, and 66 degrees battery = 47.0A
Regen brake amperage at 23 degrees OAT, and 23 degrees battery = 26.0A
Regen brake amperage at 15 degrees OAT, and 69 degrees battery = 49.5A
Regen brake amperage at -15 degrees OAT, and 60 degrees battery = 42.0 A
The following actual data shows battery amps ( regen pink and assist green ) as a near linear function of battery temperature with no regard for outside air temperaure.
Sorry Willard... there is no implementation of "cold weather regen reduction".
However, since cold outside air usually means a cold battery pack, this may have lead some folks to the illusion than cold outside air reduces regen brake. IT DOES NOT. Keep your battery warm by parking indoors, or using a heater, and you get FULL REGEN BRAKE ability in the dead of the coldest winter.
There is nothing to debate. This has been proven for the 2005-2007 models and very, very likely holds true for all models of FEH.
-John
FEH Specialist
Regen brake amperage at 75 degrees OAT, and 72 degrees battery = 50.0A
Regen brake amperage at 60 degrees OAT, and 75 degrees battery = 52.0A
Regen brake amperage at 44 degrees OAT, and 72 degrees battery = 50.0A
Regen brake amperage at 33 degrees OAT, and 69 degrees battery = 49.0A
Regen brake amperage at 23 degrees OAT, and 66 degrees battery = 47.0A
Regen brake amperage at 23 degrees OAT, and 23 degrees battery = 26.0A
Regen brake amperage at 15 degrees OAT, and 69 degrees battery = 49.5A
Regen brake amperage at -15 degrees OAT, and 60 degrees battery = 42.0 A
The following actual data shows battery amps ( regen pink and assist green ) as a near linear function of battery temperature with no regard for outside air temperaure.
Sorry Willard... there is no implementation of "cold weather regen reduction".
However, since cold outside air usually means a cold battery pack, this may have lead some folks to the illusion than cold outside air reduces regen brake. IT DOES NOT. Keep your battery warm by parking indoors, or using a heater, and you get FULL REGEN BRAKE ability in the dead of the coldest winter.
There is nothing to debate. This has been proven for the 2005-2007 models and very, very likely holds true for all models of FEH.
-John
FEH Specialist
What would you do if/upon "striking" a patch of black ice during coastdown(***) regen in that case..??
Quickly shift into neutral, **** QUICKLY..??
I think I'd rather, MUCH rather, trust to the Ford engineers to have put their US patent to good, appropriate, use.
*** If actual braking is being used it could be that OAT is ignored and regen may reach 40HP, but will be FULLY cancelled the INSTANT ABS is determined to be needed. Note: With the instant disabling of regen no actual ABS activation may be required. This latter "part" is explicitly spelled out in your owners manual
