12v battery age reset

[garageman402]

I've read a lot of posts here about 12v battery failures, SOC, & monitors. All have been 5 or more years ago, so I thought I'd start a new thread.

 

 I recently acquired my 2014 C-Max Energi SEL from my sister in law who is no longer able to drive. She bought it used from a Ford dealer in 2017 with 25k miles. At my insistence she purchased the extended warranty. That car has over 500 computers in it & only Ford (at that time) had the software. I said if you want to buy that car, you have to buy that contract. She also got the service contract & the (worthless, IMHO) $2500 anti theft rider.

 

 Anyway, she immediately had a dead 12v battery, took it to her local dealer (not the selling dealer 30 miles away) & they said it wasn't covered. She raised a stink & I think she took it back to the selling dealer & got it replaced. In either event, it was replaced. I had plugged it in whenever she came over, & the most I could get on the battery range meter was 14 miles. She has since always taken it to the local Ford dealer for every service they tell her to. Battery was replaced 11/21/23. She never plugged it in, I think the only time it was ever plugged in were the (very) few times it was at my house. Just before I got it she only drove a lot of short trips. Her daughter said if I leave it parked very long, battery will go dead. It had 33k miles on it, she only put 8k on it in 7 years.

 

 I have been plugging it in every night, got the battery range up to 19 miles. From what I've learned on this forum is there is a 12v battery life counter that regulates charging based on battery age, so I got FORScan lite & the required adapter & checked the battery age. 3772 days! That was October of 2014, so the meter had NEVER been reset. This after two new batteries (that I can confirm) installed by Ford dealers. The computer thought the battery was pretty much a ghost I presume. I think the SOC was around 64% on FORScan. I called the (most recent) dealer to confirm the battery was replaced & advised them to tell their techs to reset the monitor, then I reset it.

 

 What I notice now is that my battery range increased to 29 miles! Is that based on the  HVB not continuously charging a very old 12v battery? The SOC is now a lot better too, last I checked I think it was low 90s.

 

 One of the first times driving it, when I got on the throttle it blew all the built up condensation out of the exhaust. I looked like a skywriter, talk about a smoke screen!! I now know how to use EV Only & EV Later, so if I'm taking short trips I use EV Only so the ICE never starts. Longer trips I use EV Later to run the ICE more. I've also learned to "start" the ICE in the driveway using the throttle, it only works in park, that way you can start the engine to get oil circulating instead of a sudden acceleration which would start the engine & IMMEDIATELY put it under load. It will idle on it's own for a while to get engine up to temperature.

 

 If you have had your 12v battery replaced, get the monitor reset, or INSIST if you're at a Ford dealer that they reset it. From what I've read on here, the Ford techs don't know anything about it.

 

 

[cr08]

The EV miles is likely because the dealer reset the whole vehicle when you requested a 'reset' and it needs to figure out the real mileage again. The 12v battery won't have any impact on that. Real world your EV range is not going to change.

 

But yes, I don't trust most dealers or independent mechanics to know to do the lifetime reset. Pretty much anyone who has been in the community long enough recommends owners to do it themselves after a battery replacement no matter if the mechanic/dealer said they did it or not.

Edited Saturday at 11:25 PM by cr08

[garageman402]

4 hours ago, cr08 said:

The EV miles is likely because the dealer reset the whole vehicle when you requested a 'reset' and it needs to figure out the real mileage again. The 12v battery won't have any impact on that. Real world your EV range is not going to change.

 

But yes, I don't trust most dealers or independent mechanics to know to do the lifetime reset. Pretty much anyone who has been in the community long enough recommends owners to do it themselves after a battery replacement no matter if the mechanic/dealer said they did it or not.

 

 Actually, I reset the battery life monitor myself with FORScan, the only contact I had with the dealer was by phone requesting the service history.

 

Edit: I did reset the avg mpg (not using FORScan), you think it reset battery range too?

Edited Sunday at 03:50 AM by garageman402