The above comment by wwest got lost in this thread as the subject changed, but can anybody else elaborate a little more on the matter of regenerative braking and cold weather?

As the weather has turned colder around Chicago, I have noticed a considerable drop-off in my regenerative braking. Generally speaking, until the car is "warm" I will not see any regen from braking (which I will assume is displayed on the NAV as "wheels" ==> "electric motor" ==> "HV Battery"). Even once the car is "warm," I may not see any arrows going from the wheels to the battery for some time.

Now, if I can get the car into EV, then everything works like normal: I can drive with the ICE off, and braking and/or "L" gear puts charge back into the battery. But, as the weather gets colder, getting to EV will take longer and it will happen less frequently.

Have any other 2008 FEH owners noticed no regen braking after a cold start? Does anyone know if it's just a matter of the ABS activating when it shouldn't, hence disabling regen? Heck, does regen braking even matter that much when its cold, considering the difficulty in getting to EV mode? I'm just trying to get some more info on the subject. Thanks!

-Andrew-

 

I haven't noticed the braking, but have noticed a substantial reduction in EV time. I'm still getting tolerable mileage (around 31) but I can't stay in EV while stopped at a light or in a drive through for more than 2 minutes and can't stay in EV when I get over about 15 mph. I'll look into the grille covers from the other post. Everyone in MN has them, even the school buses!

 

Regen is controlled by ambient temperatures. Brake regen is applied at 100% effectiveness at ambient temperatures above 60.degree. F. and at 10% or less effectiveness at ambient temperatures below 40.degree. F. For ambient temperatures between 60.degree. F. and 40.degree. F., the effectiveness of regen is reduced in a linear relationship with the ambient temperature.

Also, the rate at which the service brake and/or compression regeneration is removed as a consequence of wheel slippage is reduced at warmer temperatures, such as above 60.degree. F., where true skidding is less likely to occur. Similarly, the rate at which service brake regeneration is removed is accelerated at a lower temperature, such as below 45.degree. F., where true skidding is more likely to occur. For ambient temperatures between 60.degree. F. and 45.degree. F., the rate of removal of the service brake and/or compression regeneration is gradually increased as the ambient temperature decreases. The result is a system where service brake and/or compression regeneration is removed far more slowly during warmer temperatures, where it is more likely that wheel bounce only is the triggering event for activation of the anti-lock braking system and where application of as high a level of service brake and/or compression regeneration as possible is most desired.

Queenfan, if you turn the climate control system off while in EV, coolant will stop circulating from the radiator to the engine. This will keep the engine warmer and you will stay in EV longer.

Remember folks, you can shift to neutral above 6mph and tap the brakes to go EV if "L" or tapping the brakes in "D" does not work in cold or hot weather.

GaryG

 

It is currently 35 degrees in Southwestern Pa. I have noticed a decrease in regenerative braking with the recent onset of colder weather.

 

Folks,

The amout of Regen is primarily controlled by BATTERY TEMPERATURE, not outside ambient temperature.

Now I have an engine block heater, and a HV battery heater. When I leave for the day at 26'F and have a battery temperature of 70'F and an engine block of 100'F, the car behaves just like a 70'F day.

I drive 10 miles one-way to work, and I have FULL REGEN at 26'F and FULL EV ability after 0.7 miles of driving.

Most of what Gary posts comes from reading "free patents online" that do not mention anywhere they were used in the Ford Escape, and may not even exist in physical form. He does not understand that 99% of all patents are just ideas, and fewer than 1% get built. He gets some info from unreliable sources, and re-posts unrelated information that sounds technical, without understanding what he writes. This is my primary gripe. People who write stuff without understanding it, just because it sounds good. Consider nearly all of his driving is on the southern part of Florida and take it with a grain of warm, Florida gulf-coast salt!


REGEN is ONLY eliminated AFTER a skid has begun and wheel slippage is detected. There is no "rule" based on outside temperature.
-J

 

It is true some of my info comes from the 150 plus Ford patents for the FEH, but I don't pull information out of my a** like this post.

While the HV battery does play a part by accepting a charge, it does not effect the ABS system like regen. Most likely, all the temperature sensors like for the HV battery and MAF are evaluated by the PCM, and that's why you can still have regen in lower temperatures.

Your fooling the PCM with that block heater and it's fooling you back. When you first start your FEH after using a block heater in a garage for 3 hours, it's like it sat in over 100 degree weather. That radiant heat from the block spreads to everything in the engine compartment and will effect sensor readings. Cold soak engine sensor readings at start-up must be effecting the control of regen. I know when it's cold here, I can get regen back after the engine and battery warm up also. If you think Ford didn't use this strategy safety for vehicle control of the ABS system, fine.

GaryG

 

Looks like the gloves are off for gary and gps, but I must tell you that I learned volumes about FEH temperature behavior by reading both of your last posts. Its amazing how we can deduce factual data from 2 opposing points of view.

 

The difference between us is, He reads articles on how the car might work.

I go out and measure how the car in my driveway actually operates!

One example:
For 2 years Gary told everyone that "neutral" disconnects the wheels from the transmission, thus, coasting in "neutral" was "way way better" for MPG than coasting "in gear". Something like 36% better was it Gar Gar?

I told him that was false 2 years ago, when I rolled my car down a hill from a dead stop at the top to dead stop at the bottom in both "D" and "N" and the car stopped in the same place each time, thus, there is no less mechanical drag on the wheels in N compared to D. There is no "neutral" in this car. When you push it or tow it, you are spinning the gearbox and electric motors. Hard to believe, perhaps, but so is getting 60+ MPG in an SUV! Simple truth is, it does no harm spinning the motors when in tow.
But he thought based on all previous knowledge of other cars, that neutral would disconnect the wheels. Since he believed it to be true, he told everyone it was true. I had to take pictures and video to show him this was false, since my words were not good enough.

I have learned one or two things from Gary, for sure. And found out some things sooner, because he got me looking at it. But it's lop-sided 3:1 the other way around!
Enjoy your car. The more you learn, the more you will love it!
Who knew a daily commuter car would turn into such an enjoyable hobby!

 

It's starting to get rather funny how gps tries to run me down to make himself feel taller. All and all, I think people learn something though.

GaryG

 

Somtimes things sound personal, but really, it's not, and all in the quest for truth. Sometimes I feel Gary's quest for high MPG exceeds his quest for truth, but there are always fun, interesting conversations in the process. I think Gary and I are more the same than different. We've never met in person though. I hear there is a fan club starting though, and even a request for a weekly webcast of the debate of the week!
-John