FEH High Voltage Battery Level
 

I have had an 09 FEH for 3 months now with about 3100 miles on it. My High Voltage battery level indicator never appears full, and rarely much above 50% charged. Now that it's spring (average highs of 40F) and I'm past the 3000 mile mark, I'm concerned about the health of the high voltage battery if it never has a charge above 50%.

Does anyone have any thoughts or experience with this - should I give it a little more break-in before having a dealer look at it?

Thanks in

Re: FEH High Voltage Battery Level
 

I have seen it printed that the HV battery is cycled between about 40% & 60%.

I think Ford did this to keep safe from two things:

First an inability to start in even the coldest of circumstances.
Second to prevent overcharging the battery with attendant problems.

This is probably quite conservative but it gives them room to grow once they get more info on how the batteries do.

I believe you find this on the wikipedia site.

Re: FEH High Voltage Battery Level
 

Your battery is just fine and the maximum the generator/motor will charge your battery is 52%. This allows 8% to be charged on top of that with regenerative braking to a maximum normal range of 60%. There will be times the computer will calibrate the battery to over 80% charge to keep the battery operating as long as possible in our vehicles. Ford designed this 40 - 60% operating range to get as many charge/discharge cycles as possible.

GaryG

Re: FEH High Voltage Battery Level
 

Thanks for your replies.

Re: FEH High Voltage Battery Level
 

Just to add my thoughts, Honda's Hybrid system allows charging up to 80% state of charge. There have been a number of individuals at Greenhybrid.com having issues with Honda's hybrid battery at the 80-100,000 mile range. The Honda and Ford system are not similar but I wonder if allowing charging up to 80% state of charge is not good for durability purposes.

Re: FEH High Voltage Battery Level
 

If you look at the chemistry of the batteries they produce water tht can pressurize the cell container.

Batteries charge on an non-linear curve. My bet is that Ford chose the most linear region that would both:

a. Retain enough energy at the low end to start the engine in the coldest of environments if the engine was shutdown just before it was to be cycled on.

b. Keep the high end from damaging the battery cells if an error in the system caused some overcharging.

My bet is that they have a small program in each cars computer/controller to record data that is downloaded to Ford when you go in. They have a real need to collect battery performance data to improve their cars. If they could open up the charge band some it would give better engine off performance.

For example as I hear it the new Ford Fusion hybrid can get up to 42 mph before being forced to start the ICE. I believe that part of the performance improvement comes from better knowledge of the battery performance band.

Re: FEH High Voltage Battery Level
 

Maybe you are correct. The Fusion Hybrid has a new battery composition that is suppose to provide more energy (20% is that what I read?) per cell. I understand the Fusion Hybrid can travel up to 47 mph in EV mode!

Re: FEH High Voltage Battery Level
 

I don't know if things changed in 2009 *(probably not) or if GaryG made a typo...

The correct numbers for 2005 thru 2008 models:

The HV battery charges via generator to 53% SOC.
53% is the preferred SOC and the battery will remain here and only deviate slightly during crusing. It will go down to 40% and up to slightly higher than 53% during stop-n-go conditions. To get a lot higher than 53% you need a long ( many miles ) downhill stretch of coasting or braking.

HTH,
-John

P.S. I've found no "maximum" range for the battery. The 40% to 60% is quoted in some places as "normal".... but normal is really, and exactly, 53%. If you are lower than 53%, you are below normal. Higher than 53% is considered higher than normal charge.

Below 53% and the car does it's best to recharge. Above 53% and the car tries to discharge. Only at exactly 53.0% does the car do nothing.

Re: FEH High Voltage Battery Level
 

I'd be interested in seeing your source. Mine was from a lengthy wikipedia article that showed much of the battery cycling. I'll go back and find it for you.

The more I see of this kind of stuff the better I understand how & why the machine does things. Once I figured out how little of the range of the battry charge they used (though I thought it to be greater than it turned out to be) I began to wonder what other software limits Ford put into this machine.

Protecting us from ourselves and themselves from lawsuits while advancing engineering for the common man!

Re: FEH High Voltage Battery Level
 

My source is my car with 100's of dollars of additional instrumentation added, plus 4 years of ownership with reverse engineering, plus, something you can do as well, is read all the posts in this database and find dozens of others posting the exact same results!

What else would you like to know?
I've taken apart and studied most aspects of the 2005 Ford Escape Hybrid, and the models have changed very little over the years.
:D

Re: FEH High Voltage Battery Level
 

No typo John, the question Wax 1973 ask was about the '09 FEH which you do not have. Ford did make many changes to the '09 and I have the same issue that Wax1973 has. Not having hills to charge the battery with regen I rarely see over 51% SoC. I've gotten 52% after a long highway trip and braking on the exit ramp. Ford may have lowered the SoC range to allow more regen space for long downhill trips or better MPG on the highway.

GaryG

Re: FEH High Voltage Battery Level
 

I asked for your source because I seek to learn more. Your response seems arrogant.

I looked up my Wikipedia source. It notes the SOC (State of Charge) as right on your numbers, which it should since they cited you as the source.

This is all observed, and therefore anecdotal info. Please advertise it as such in the future.

To advertise it as anything else is to claim an inappropriate credibility. For example what is the specified accuracy of your instrumentation and when was that accuracy last checked to a standard?

Now that I know the Wiki article is based solely on one persons observations I will give it less credibility.

For example your numbers, and those in the Wikipedia article, are curbside numbers, not numbers underway at power. The way the system is programmed to operate at power may be different.

I am interested first in how the system is programmed to operate, then how it performs in the real world and thus how it measures up.

Re: FEH High Voltage Battery Level
 

This is a photo of the highest SOC I obtained during driving:
Attachment 3207
68.6% SOC which occurred in Maryland during a long over 2 mile downhill. I do not know how high the SOC would be on a longer downhill.

Re: FEH High Voltage Battery Level
 

Interesting... I'm curious, was that obtained in "D" or "L"? Thanks!

Re: FEH High Voltage Battery Level
 

d

Re: FEH High Voltage Battery Level
 

As long as the FEH is moving forward under power and running on the ICE it should not make a difference in those numbers. But it would be interesting to know if it did. The manuals advertise "L" as only increasing the charging output to the traction battery when braking or coasting.

From the 68.6% SOC above I infer that the charge discharge cycle when underway (instead of curbside) is a broader range. My guesstimate from experience watching submarine batteries (different chemistry) over the years is that the underway curves of charge & discharge is about 30-40% to about 70-80%.

So the bottom end isn't too far off but we'll have to refine the top end a bit.

This is just based on my behind the wheel observation of the system.

Re: FEH High Voltage Battery Level
 

the first week I had my FEH, my mother needed to move. Bad part was she moved up to big bear mt. On the way down from Big Bear (no SG) my green batt bars got all full. Well all but the top bar. I remember asking my wife to dbl look that I was seeing it right.

I'm sorry to say I dont know the % with out a SG.

Re: FEH High Voltage Battery Level
 

66% is the max for my 2008 FEH, on a long downhill. The engine began to spin at this point (to about 4K RPM), although the SG indicated 9999 MPG, i.e., no fuel being used.

Re: FEH High Voltage Battery Level
 

Sounds like you might have been in "L" for engine braking. That is how mine behaves when there is no more "room" in the battery and the braking has to be doe somewhere else, like compression braking by the engine.

It very rarely does this when in "D," even on long grades.

True?

Re: FEH High Voltage Battery Level
 

I think I was in and out of L, based on my speed, it was in the mountains.

Re: FEH High Voltage Battery Level
 

Yeah, been there. Got it and think I know how to use it.

Many thanks.

Re: FEH High Voltage Battery Level
 

I don't think the phenomenon that you describe as compression braking is exactly that at all. I believe that the ice is being spun by the motor to "burn off" excess charge. I say that because when the ice takes off on a tear like that from overcharge, the vehicle can be at a dead stop, or be brought to a dead stop, and the can still be whizzing away.

Re: FEH High Voltage Battery Level
 

Bill, What is your question?

Pose a lucid, intellegent question, and I will give the what you would like to know. I posted 100% accurate information about the 2005-2008 Ford Escape Battery pack and its control software. What would you like to know?

Either the 4 vehicles I have driven, disassembled, and studied are "unique" or, since all 4 behaved the same way, they are typical of how the Ford Escape Hybrid operates. My credentials are below Ford's but far out weigh yours in this area of expertise.

So now ask a valid question or get off the proverbial pot.
Thanks.

Re: FEH High Voltage Battery Level
 

People get confused with wording.

"Compression brake" is just that.
It does not matter if the wheels are spinng the engine without fuel, the engine acting as an air compressor, or if the traction motor is putting resistance on the wheels, generating power, sending the power to the generator, and then in turn, the generator spins the engine without fuel, acting as an air compressor.

The FEH still has 'engine compression braking' just in a more complicated way.

HTH,
-John

Re: FEH High Voltage Battery Level
 

Re: FEH High Voltage Battery Level
 

No argument that the system uses the engines compression for braking.

I am not convinced that the phenomenon where the ice runs up to burn off excess soc can be called compression braking. Seems to me that in those situations the ice speed is independant from the vehicle speed.

Different situation.

Re: FEH High Voltage Battery Level
 

gpsman1: Didn't pose a question, sorry.

Experience combined with anecdotal information does not equal credentials.

Please send your credentials in a private message.

Re: FEH High Voltage Battery Level
 

Keep in mind that the computer controller can spin the ICE at what ever speed it selects.

The energy of coasting downhill has to go somewhere. Vehicle speed increase, battery charging, or engine friction and compression (note that engine internal friction is a smaller part of engine braking or compression braking).

In my observation when in "L," and when the battery has attained a certain state of charge, the controller spins the ICE up and it absorbs the energy of braking. I have seen the engine at about 2500 to 3000 rpm and also at around 4,000 rpm.

My take is that the software is programmed to set the engine where it gives the requisite braking (ie rpm setting & fuel setting) for the counter-torque being demanded. The characteristics of this are different when in "L" than when in "D." In "L" it comes on much more readily.

I suspect that is just how Ford intended "L" to be used since, by the manual, it does not add to the power on mode, only the power off or coasting mode (& I don't mean engine off but simply foot off the gas pedal & coasting).

Re: FEH High Voltage Battery Level
 

Here is a statement I made on the FEH Yahoo site and a PM from a Ford FEH Engineer:

> I've been saying all along that the FEH does not have real engine
> braking. In fact, another Ford patent explains that Ford Engineers
did
> not want to allow engine braking to take away from the benefits of
> regenerative braking. This does not mean the one-way clutch can't
> allow real engine braking through programming though, it just means
it
> may be a last choice.

Ford FEH Engineer:

As with many of the sweeping statements made
about the FEH system behavior, one
must he careful to qualify whether a
statement applies to the 0-40�mph range
when ICE may be off or potentiality
could shutdown and the range above
40 mph where ICE is always spinning. The above statement is correct
below 40 but wrong above 40. Clearly you don't
want to waste battery power by having the
traction motor turning the ICE when
driving the vehicle forward. That's the
situation under 40�mph. But above 40 its a
whole different control regime.

My '09 FEH has a completely different control regime than the '05 - '08 FEH.

GaryG