I have a 2010 Ford Escape Hybrid and have nearly 150k miles on it. The vehicle has been performing well since I purchased it until the last few weeks. From time to time, with no particular pattern, the hybrid battery is completely discharged. I notice when this happens because the vehicle runs rough; the gasoline engine is attempting to both handle the motion of the vehicle while simultaneously charge the hybrid battery. What is interesting to me is that after the complete discharge, evidenced by looking at the system monitor showing no bars on the battery from the console screen, running the engine will indeed charge the hybrid battery. When I park the vehicle after having run the engine for about 5 minutes, the battery does hold the charge. In fact, the battery will continue to charge to about 75% of capacity and stay that way for a few days, up to a week before completely discharging again.

Is there any reason this should be happening? My vehicle is currently at the dealership, where they are attempting to watch it occur and "fix" the problem. Unfortunately, nothing has happened for the last 4 days. I am also curious if there is some system setting that could be corrupted resulting in a forced complete discharge.

Any information would be greatly appreciated.

 

That behavior sounds identical to a negative recalibration in a Honda IMA system.

This thread describes a reconditioning process:

http://escape-city.com/viewtopic.php?f=38&t=12504

I wonder if what you're seeing is the opposite to this... It's reconditioning the pack at the bottom end instead of the top end?

 

I have a 2012 FEH and mine will occassionally discharge overnight from about 50% charge to 1 bar. Like you said the engine aggressively charges the HVB when this happens and it has a very noticeable impact on the performance of the vehicle. Is yours discharging while parked or it is happening gradually while you drive?

 

It only happens when the vehicle is parked, and is allowed to sit a minimum of 3 hours. I took the vehicle to the dealership a week ago, and it was there for a full week. During that time the hybrid battery never lost any charge. I'm beginning to think it has something to do with my commute. My commute as about 45 minutes to an hour, with 50% at 65mph. Then, during the last leg of my trip, I end up driving about 2 miles on the hybrid battery because the speed limit is 25mph. When I stop, I have been checking my battery indicator and typically see a minimum 50% charge. When I go back to my car to go to lunch, that is when I'll notice once or twice a week that the battery has no charge.

 

Ok, your symptoms are similar to mine then. I haven't figured out what triggers this. For me it happens about once every 2-4 weeks. Is it possible that a relay or something isn't disengaging the HVB after the vehicle is turned off and there is a small current draw on the HVB that is discharging it? I don't know. It happens infrequently enough that I doubt the dealer would be able to replicate it. I don't get a check engine light or anything which leads me to believe the vehicle doesn't think it's a problem worth telling me about. So I don't know...should we be concerned about it or not?

 

IMA doofus chiming in again...

On the Honda IMA, if the 12V battery gets weak and goes low voltage, it can cause a BCM reset where the car thinks the battery is at 0% SoC and then enters a forced regen phase.

As an AZ resident, I'm accustomed to routine 12V battery failures in the 2-3 year timeframe, so that's the first place I tend to look. Could a weak or failing 12V be contributing to this issue?

Steve

 

Brian,

Should we be concerned? I think so. It has a negative effect on the performance of the vehicle through lowering the gas mileage. With the engine spending additional energy to recharge the battery, that energy is lost with the charge of the HEV battery loses all that energy - it is synonymous with dumping gasoline on the ground.

To help in my situation, I contacted Ford Corporation's Customer Service department. They were eager to know what was happening and that the dealership was unable to fix the issue. Ford also said that when these sorts of issues arise, they are required by law to contact the National Highway Safety Administration. So if you are reading this post, and have the same issue, contact Ford and let them know.

One thing I was curious about was the capacity of my standard 12V battery. It's only 18 months old; had to get a new one because charging my phone in the car to often killed it. But the battery for the gasoline engine was checked and is in good condition. So it's not the 12V battery's charge.

I am curious though, does anyone know how to "scope" a Ford HEV? I'm interested in renting the device to monitor the error codes that could possibly be produced when the hybrid battery loses its charge.

 

One quick and dirty test would be to disconnect the HV battery with the switch on the battery pack. IIRC there's a red rotary switch on top of the battery. Maybe disconnect the pack here and confirm that the discharge path is outside of the battery pack.

After that I might pull some fuses and relays and measure any current present when all systems are switched off. It would take a significant amount of current to discharge the HV battery overnight. Shouldn't be hard to find where that current is going. A clamp-on ammeter might be useful.

 

I have two 2012 FEH and one 2011, which have similar HV
batteries to your 2010. None are driven every day, and one
is lucky to be driven once a week. That said, I've never
observed your problem in any of the three, or my previous
2006 FEH.

I concur with Don's suggestion to use the disconnect switch
to determine if you have a self discharge problem--doubtful.

I'd also suggest purchasing a ScanGauge II to display the HV
battery state-of-charge (instead of interpolating NAV display
battery bars), temperature, and voltage, as well as other FEH
sensors. https://www.scangauge.com/support/x-...cific-xgauges/

 

You could try forcing the engine to run during this portion of your drive and see what effect that has. You can force it to run by selecting an hvac setting using the air conditioning, and turn the "eco" mode off.