Hello. First time poster here. I have a 2012 Ford Escape Hybrid and have a question.

Occasionally when the key is first turned to "start" the vehicle the ICE will immediately kick on even before putting the vehicle into drive. When I switch the screen on the NAV system that shows the SOC for the HV battery I see that it has one bar when this happens. Normally the SOC stays somewhere in that 4-8 bar range. The ICE is clearly trying to aggressively bring the SOC back up. While it is charging the HV battery accelerating from a dead stop is slow and sluggish which makes sense because the SOC is below what I believe is considered normal. After the SOC is brought back up behavior and performance from the vehicle returns to normal. I asked my wife how often this happens and she said maybe once every month or two.

So, is this normal behavior? Why would the HV battery discharge (or at least appear to discharge) overnight while sitting in the garage?

 

Though I have an '09, and I understand the '10-'12 is different in how it handles startup, I'd guess what you are seeing is normal. The '09 and older never start without the ICE starting up, even for a few seconds.

Performance is sluggish at first because even though the ICE is running, it's only recharging the traction battery, and propulsion is electric only for about a block.

If your SOC is normal or high when it's parked, and low when started the next time, this would indicate a problem. But sometimes, such as if you maximize electric only use just as you arrive home, it will be low when parked, and so it will be low to begin the next use.

I live on a small hill, and try to use electric-only as I arrive home. This way, when I use it next and the gas engine is running at 1500rpm to warm things up, the excess energy is being used to move the thing and recharge the traction battery. Unless someone can correct me, I think it's good to park it with the battery low.

 

Thanks for the response. I really appreciate it.

Yeah, so on my '12 FEH when you "start" the vehicle the ICE usually does not come on. It is only when the vehicle reaches 5-10mph or when there is a significant power demand that it will turn on. At which time the ICE is in warm-up mode and stays on until the warm-up is complete. So having the ICE kick on immediately is definitely atypical for my model year.

I think the thing that has me mildly concerned is that when we park it we usually do have ~40% charge in the HV battery and then the next morning it is suddenly 10%. It is my understanding that the SOC should not be dropping below a certain threshold. In fact, isn't there a low-SOC cutoff that will disconnect a relay to prevent further discharging? The thing is that this happens infrequently enough that I'm not too concerned about it especially since the CEL does not come on. But, it has happened enough that I have noticed. Could this be a normal battery maintenance operation?

If it happens again (and if I think about it) I'll see if I can pull off any diagnostic codes with my OBDII reader. The problem is that I don't think it reads the proprietary Ford protocol so I'm not sure I'll be able to get anything useful from it.

 

The hybrid battery occasionally goes into some sort of self-maintenance cycle, discharging and charging itself. I've never noticed mine do this, but people who know more about the FEH have described it. It may be you're turning it off at some point in that cycle. The only other explanation I can think of is that there's a short somewhere in the hybrid battery. As you say, it's supposed to completely disconnect from the vehicle when turned off.

The '10+ start routine is much better than the previous. I can't get a block from my place without having to stop for a traffic light. Never. So the FEH sits there idling like crazy at 1450rpm to warm things up, GUZZLING gas, and going nowhere. I've gotten into the habit of shutting it off if the light is going to last a while, and at those times I wonder why the car can't shut down until it's moving.

OBDII readers of less than professional grade seem to be ignorant of many of the important codes in the FEH. I think diy car owners should start a petition to demand the government force the car makers to include in the instrument panel displays a means to display the codes. You know the minute detailed things the Escape can display, why the hell not these codes? (Of course, it's to screw the folks who keep these companies in business.)

 

OP, I highly suggest you pick up a ScanGauge2. It's the only way I know of to get an actual number for SoC. The bar graph on the NAV unit is better than nothing but I don't think 1 bar corresponds to 10% SoC (someone correct me if I'm wrong). It would be very detrimental to the battery's lifespan for it to drop that low, so hopefully it isn't. But without a ScanGauge it would be hard to tell how low it's getting. You're correct that it shouldn't be dropping appreciably when the car is parked though.

When I first got my 2010, I had kept something plugged into the rear 12V power port that was drawing more energy than I thought it was. I too had a mysterious overnight drain in the traction battery and scratched my head a while before figuring out that I needed to unplug the 12V accessory. What was happening was it was drawing from the 12V battery, and the traction battery was then dumping a bunch of charge into the 12V battery to charge it back up.

So I would first check to see if you have anything plugged into the 12V outlets--both of them are "live" 24/7 and do not switch off with the ignition.

Barring that you might check the age/capacity of your 12V battery. For a 2012 built in 2011 the OEM battery would be about four years old. Should last longer than that, but unless you're the original owner you never know if a previous owner didn't take care of it.

I've read others report that sometimes a relay can get stuck on leading to battery drain. Unless it's defective though it shouldn't be happening every time you park the car.

 

Thanks bookemdano. The stuck relay theory seems like the most logical. And, no, it's not happening very frequently. I'll keep an eye on it.

And yes, I have been meaning to get to a ScanGauge. I've been putting it off for a long time.