2017 FFE Normal battery degradation?

[vkdyer]

My range has dropped over the last couple months. Since my last full charge, I've driven 85.5 miles over 3 days with 8 trips. The battery shows 10% remaining (and only 5 miles). If I add up the kWh for the 8 trips, it comes to 18.5 kWh. The battery has a stated kWh of 33.5. So according to these numbers, I used 90% of the battery but only 18.5 kWh. The car will be 8 years old in April. Is this normal degradation or does it sound like something is wrong?

 

[jghall00]

If you use Forscan, will tell you the remaining kWh in the pack at full charge. Mine was around 25.8 with 68K.

 

[Anti_Climax]

My range has dropped over the last couple months. Since my last full charge, I've driven 85.5 miles over 3 days with 8 trips. The battery shows 10% remaining (and only 5 miles). If I add up the kWh for the 8 trips, it comes to 18.5 kWh. The battery has a stated kWh of 33.5. So according to these numbers, I used 90% of the battery but only 18.5 kWh. The car will be 8 years old in April. Is this normal degradation or does it sound like something is wrong?

33.5kWh is not the available capacity, it's the direct raw capacity of the cells. 100% is 95% SoC and 0% is about 8.5% SoC. So even when absolutely brand new, the available capacity is 29kWh. What you're seeing here suggests your capacity has dropped to about 70% of the nominal value.

If it's been abrupt and recent it could be a single cell triggering the discharge limit before the other cells are near it. In which case the capacity is there but it can't be safely used without drawing a cell down below spec. Going too low on series cells can do REALLY nasty stuff like flip their polarity.

Beyond that, they do have a finite lifespan that targets around 80% after 8 to 10 years. But that is tied to a bunch of factors that vary widely by drivers. At 4-5 years, my original battery had lost around 25% of the available capacity but I have no idea how the original owner treated it. My replacement hasn't degraded nearly as much in the same timeframe.

 

[Sftbldad]

My range has dropped over the last couple months. Since my last full charge, I've driven 85.5 miles over 3 days with 8 trips. The battery shows 10% remaining (and only 5 miles). If I add up the kWh for the 8 trips, it comes to 18.5 kWh. The battery has a stated kWh of 33.5. So according to these numbers, I used 90% of the battery but only 18.5 kWh. The car will be 8 years old in April. Is this normal degradation or does it sound like something is wrong?

First thing you need to do is check your warranty date on Ford.com. These batteries do not degrade because of use like stated by others there are 2 cells that seem to take the brunt of charging and discharging. Warranty battery packs run anywhere from 24Kw up to around 27Kw (available) If you’re still in warranty which you should be. Your car is covered to retain 70% capacity at 8years 100k. If you are dipping into the 80 mile range it’s time to head to the dealer. Mine went from a 100 to the 70’s in a couple months… Plus remember Ford also covers $40 a day rental charge. They paid almost 3 grand for mine…If you go the dealer route call customer service for and open up a buy/back claim…. This gives you more options because Ford will make you an offer on the car but it takes time and the average repair runs 30 to 90 days…(depending on battery availability)… Good luck…

 

[vkdyer]

Thank you both for your replies. I've got a charge log going back to day 1 (April 2017) and a trip log back to March 2023 (after the new tires I put on dropped my range), so I have numbers, but not the knowledge for interpreting them. I tried using my OBD scanner on it and couldn't get it to connect, and I've read enough now to know I'll need a different one to try Forscan. I've loved this car so much, but with the range going under 100 miles now, it's getting to be a problem. (I once got 140 miles out of it in the summer time.) Since the battery warranty is running out soon, I'm thinking I will need to trade it while I can still get something for it. This is a great little car, and if I could wave a magic wand and get a 200-mile range, I'd keep it forever.

 

[Anti_Climax]

You can get the capacity without Forscan, it's just more tedious. Top it all the way up, clear one of your trip meters, drive until it's nearly at 0%, and then park it and run the heater until it hits 0. You're 90% of the way there, so I wouldn't expect it to give you a drastically different reading than what's been estimated here ForScan will let you check cell voltages to see if any are particularly problematic.

But there's no single range that's "good enough", it's always "good enough for you". Someone else could get a few more years of of it.

 

[vkdyer]

I appreciate the advice. I was hoping I could get something out of FORScan, but I seem to be struck. I got it installed on a laptop, and I seem to have the right kind of cable now. I'm not quite sure what I'm looking for, but if I try to test the BECM Module, I get a message saying I need an Extended License. I found where I thought I could generate a free one, but it said I'd entered an incorrect name. Then I found where I needed to sign up for the FORScan forum to get registered, but I couldn't register, because it said it was only open to paid members. I could get one test to work that showed "no fault" on any of the battery cells I added to the dashboard.

I guess I just need to take it down to the dealer and try my luck. This car has never been to the dealer ever. When I bought it, the local dealers (Tennessee) couldn't (wouldn't?) get me one, so I bought it from a dealer in Maryland and had it shipped to my house. I have always wondered if the local dealer would even be able to work on it, since I don't think there are any others around. In the almost 8 years I've driven it, I've never seen another one on the road. I've even had people tell me that Ford never made an electric Focus.

 

[vkdyer]

I think I finally got something I understand out of FORScan. I charged it up to 100%, and the BAT_TO_EMPTY_ESTIM_KWh reads 20.298. I've got 51k miles, and I'm still inside 8 years, so I will see if that will get me a battery replacement or a buyout offer. Thanks all!

 

[Anti_Climax]

You should also be able to check cell voltages. Verify them at full charge and again near discharged to see if there are outliers. If there are it's more ammo for a warranty replacement.

 

[vkdyer]

I found the cell voltage check in FORScan. Cell 1 = 3.769, Cell 15 = 4.000, all the others are between 3.989 and 3.995. That's with the battery mostly charged (92%). I'll drive it around and run it down and compare. From this, it doesn't look like anything looks bad.

I took it to the dealer today and told them my story. I've got an appointment in 3 days to take it back to them, and they will check it out.

For all the years I've had the car, whenever I've charged it, when it's finished charging, the lights turn off on the car, and it also turns off the charger. A couple months back, it quit turning off the charger. All the lights are off on the car, but charger still has the "charging" light lit up. I hear some noises around the car, like something is still happening, but no lights are on. I've been just unplugging it. When I check the battery settings, it shows it's charged to 100%. Since this started, I haven't charged it overnight any more. I check on it, and unplug it as soon as I see it's done. Not sure if this could cause battery damage or not.

 

[Anti_Climax]

There is a balancing mode where cells are isolated and float charged independently to try and get them to the same value. My guess is that it's in that balance mode trying to get the voltage on cell 1 up, which requires the EVSE to stay energized.