Regenerative brakind disabled, what did they do?

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Old Dec 19, 2008 | 04:46 PM
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Unhappy Regenerative brakind disabled, what did they do?

Talk about a frustrating situation. Took the FEH fro a leaking rear diff seal, all to be fixed under warranty. Pick up the car at closing time, start to drive home. Notice that regen braking is acting weird, seems to be going on and off. Then, with a 'a big what the What', I notice that my scang says BTM is 30%? Except during a reconditioning event, I've never seen it that low, and it doesn't seem to be climbing.

Finally after about 20 minutes of driving home, 'Beep, beep,' a message appears that says regenerative braking is disabled. So, what on earth did those mechanics do to my car?! What on earth could they have done to run the bat down so low? The frustrating part is the service department is now closed til monday, but I'll be there first thing!

Given the time of year, I really need the vehicle this weekend, but given the situation so far, I'm scared of it shutting down entirely!
 
Old Dec 19, 2008 | 04:50 PM
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Default Re: Regenerative brakind disabled, what did they do?

Meant to add, that by the time I got home, batt had only climbed to 38.6, and was charging very very slowly compared to normal.
 
Old Dec 19, 2008 | 06:00 PM
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Default Re: Regenerative brakind disabled, what did they do?

Always try the simple --shut off the vehicle, wait a few minutes and then restart. Another method would be to pull off the negative battery cables, wait and re-attach.
 
Old Dec 19, 2008 | 06:29 PM
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Default Re: Regenerative brakind disabled, what did they do?

There are two possibilities.

Cold climate...The regen level is significantly reduced when the OAT is below 35F and the potential of encountering an icy surface rises dramatically. Non-driver induced braking, via engine compression or regen, on the front, stearing wheels, can be fatal.

If ABS activates during actual brake pedal depression regen will be instantly disabled.

It's unclear from my standpoint how long regen will remain disabled in this latter case.

An improper OAT readout might cause your problem, failed, open, OAT sensor..?

An ABS fault could also be your problem.
 
Old Dec 19, 2008 | 06:44 PM
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Default Re: Regenerative brakind disabled, what did they do?

Originally Posted by ranger01
Talk about a frustrating situation.

What on earth could they have done to run the bat down so low? !
I have "run my hybrid battery down to 26% State of Charge" by opening and closing the doors when I was replacing speakers and adding sound deadening material. It is possible the service manager/mechanics could have opened and closed the doors during this process while checking the "computer".

As for slow regeneration of your hybrid battery--don't fall for the outside temperature BS . I got full regeneration at below zero temperatures (yes there was snow and ice) during the 2007-08 Holiday season when I was in Northern Wisconsin visiting my Dad while he was battling cancer which ended his life. Unhook your negative battery terminal-wait-reattach and see what happens.
 
Old Dec 19, 2008 | 07:00 PM
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Default Re: Regenerative brakind disabled, what did they do?

Originally Posted by ranger01
Meant to add, that by the time I got home, batt had only climbed to 38.6, and was charging very very slowly compared to normal.
I don't know for sure, but it sounds like the tech left the key On when he switched to neutral to do the repair. This will drain the HV battery to almost nothing. In cold weather with a drained HV battery you may have been able to start the engine but the demand to charge that low of a HV battery and 12V battery in a cold climate may have caused all the problems you had. My guess is you need to slowly recharge the HV battery with the small generator at an idle til things get back to normal. You should be fine from that point on IMO.

GaryG
 
Old Dec 19, 2008 | 08:25 PM
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Default Re: Regenerative brakind disabled, what did they do?

Originally Posted by GaryG
I don't know for sure, but it sounds like the tech left the key On when he switched to neutral to do the repair. This will drain the HV battery to almost nothing.
GaryG
I've experienced that too. But I don't understand what in the vehicle is consuming that much power just by having the ignition key on. Do you know Gary?
 
Old Dec 19, 2008 | 10:38 PM
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Default Re: Regenerative brakind disabled, what did they do?

Originally Posted by wwest
There are two possibilities.

Cold climate...The regen level is significantly reduced when the OAT is below 35F and the potential of encountering an icy surface rises dramatically. Non-driver induced braking, via engine compression or regen, on the front, stearing wheels, can be fatal.
I'm a little confused as to the "severity" of that statement. What does a conventional vehicle do when its below 35F? Its going to have engine compression occurring every time. Does that mean every vehicle out there is a deathtrap once you pull your foot off the accelerator other than a hybrid?
 
Old Dec 20, 2008 | 12:44 AM
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Default Re: Regenerative brakind disabled, what did they do?

Can we have some Moderator intervention here please?
Please ask Willard NOT to post in the FEH area. He is confusing people.

Eveyone, please disregard everything Willard West posts in this area.
He does not understand the Ford Escape at all. He doesn't even own one.

Regenerative braking ( recharging ) ability has NOTHING to do with outside air temperature. It is related ONLY to the internal temperature of the battery pack, which by useage alone, can be very warm, as warm as your cabin, or higher, even in the dead of winter.

If the battery is COLD then the amperage in and out is reduced.
This is a fact of chemistry, and is true for all batteries.

It is by COINCIDENCE ALONE that usually, if it's cold outside, and the car has been parked for a long time ( 24 hours ) then, by nature, the battery is cold also. Drive a few dozen miles, and the battery will warm up, and your regen will be absolutly normal, even at 16 below zero.

The battery pack cannot be "drained down to almost nothing" in 1 day, for example. The battery pack will disconnect at 35% to save enough power to start the car. In general, the ways the battery can get lower: A) sitting for a very long time ( 6-8 weeks ) B) If the key is turned on-off-on-off-on-off many ( dozens ) of times, without starting the car.
There are a few exceptions to this.

If you turn the key on and leave it on, for example, the battery will always disconnect itself at 35% as a precaution.

HTH,
-John
 

Last edited by gpsman1; Dec 20, 2008 at 12:47 AM.
Old Dec 20, 2008 | 06:58 AM
  #10  
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Default Re: Regenerative brakind disabled, what did they do?

Originally Posted by econoline
I've experienced that too. But I don't understand what in the vehicle is consuming that much power just by having the ignition key on. Do you know Gary?
Seat heaters, interior lights, radio, etc, or even an almost fully discharged 12 volt battery at the beginning...
 


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