New Battery = Low battery so no AC!

[Shadow277]

I got my battery replaced on last Wednesday. Now I am receiving the same message: battery low. system recharging and "low battery, some features may be disabled."

I am thinking about disconnecting the battery over night to reset it. I had the car tested to and all the computers read normal, as per Firestone.

Anything else I should do? Not having AC when it is 112F outside is not cool.

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[Jaymar]

There is a battery life monitor that usually resets after sitting for 8 hours with no activity. Might want to look into doing a reset of that with Forscan.

 

[Farkel]

Did you reset the BMS after installing the new battery? If not, the charging system thinks you still have the bad old battery. You should also lock it and let it sit for 8 hours to reset the state-of-charge.
https://www.mustang6g.com/forums/threads/bms-reset-no-tools-required.151602/

 

[Shadow277]

Did you reset the BMS after installing the new battery? If not, the charging system thinks you still have the bad old battery. You should also lock it and let it sit for 8 hours to reset the state-of-charge.
https://www.mustang6g.com/forums/threads/bms-reset-no-tools-required.151602/

Had no idea it was called BMS. Thank you kind sir.

 

[Evolvd]

Forscan isn’t needed as the reset can be done manually following these steps:

1. Turn on accessory switch but don’t start the engine
2. Within 10 seconds flash the high-beams 5 times then press the brake pedal 3 times
3. The battery indicator will flash 3 times and then come on solid
4. Turn off the car
5. Lock the car with your remote and let it sit for at least 8 hours

You should have no problems the next time you use the car.

 

[Farkel]

Had no idea it was called BMS. Thank you kind sir.

Yer welcome. Can't promise those steps will resolve your issue, but they should be done when the battery is replaced.

 

[Shadow277]

Yer welcome. Can't promise those steps will resolve your issue, but they should be done when the battery is replaced.

Unfortunately both did not work. Battery light never flickered and disconnecting the battery for 8 hours did not work.

Considering my mechanic said it is electrically fine, I am out of ideas other than asking for another battery.

 

[Shadow277]

What does the voltage read on the dash menu?

What is the date stamp on the battery?

What is the voltage of the battery after letting it sit for more than 2 hours?

I have had a junk brand new battery before so it not to uncommon.

I am the office so I have no tools to check. Might check on my lunch break. I am thinking about trying the BMS again. Maybe I did something wrong. If not, then I'll check what you asked and will probably have to take it back to Firestone.

 

[Farkel]

By all means, try the BMS reset again. Follow the directions carefully. Also, disconnecting the battery will clear the keep-alive memory (KAM), but only the 8-hour sleep (with the battery connected) will allow the system to determine the battery's state of charge.

 

[K4fxd]

If you don't have forscan take it to a dealer and have them reset the BMS.

 

[Shadow277]

If you don't have forscan take it to a dealer and have them reset the BMS.

I fear that might be my only option.

 

[K4fxd]

Forscan is free, just need a 50 dollar dongle.....

 

[The Demon]

Is resetting the BMS because his is a 2016? I changed my battery on 6/4 and did nothing. No issues at all with the car. Everything works well and the voltage is 14.4 when driving. I have never tested the resting voltage.

 

[Farkel]

Is resetting the BMS because his is a 2016? I changed my battery on 6/4 and did nothing. No issues at all with the car. Everything works well and the voltage is 14.4 when driving. I have never tested the resting voltage.

BMS reset resets the days-in-service parameter, which is one of the things the charging system software looks at to determine when and how much to charge the battery. AFAIK, this applies to all the 6G Mustangs.

 

[Jaymar]

Is resetting the BMS because his is a 2016? I changed my battery on 6/4 and did nothing. No issues at all with the car. Everything works well and the voltage is 14.4 when driving. I have never tested the resting voltage.

It usually resets itself and manages everything in the background but like all gadgets, it is prone to taking a huge dump sometimes and goes haywire. There is a thread here where some have had to disable it completely. All this monitoring and the damn battery still only lasts 3 years or so.

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