Battery voltage

[None2Slow]

I thought I read that this is how the system works. Something about it runs on the battery until it gets below a certain point, then the alternator charges it back up, then repeat. This is why it shows low at times, then spikes to 14+v.

 

[drive_55_not]

I thought I read that this is how the system works. Something about it runs on the battery until it gets below a certain point, then the alternator charges it back up, then repeat. This is why it shows low at times, then spikes to 14+v.

Old post but, Yes the S550 uses regenerative charging, The PCM cuts the alternator field to help increase gas mileage under load, then starts charging under no load coasting other factors.

On another note,, My stalling issues were caused by the drivers side VCT. Unfortunately my car went to Mustang heaven after it was killed by a DUI'er.

But at least it quit stalling ...

.

 

[ponie1992]

Old post but, Yes the S550 uses regenerative charging, The PCM cuts the alternator field to help increase gas mileage under load, then starts charging under no load coasting other factors.

On another note,, My stalling issues were caused by the drivers side VCT. Unfortunately my car went to Mustang heaven after it was killed by a DUI'er.

But at least it quit stalling ...

.

Damn, sorry to hear that man!

 

[Leosegura155]

What is everyone's battery voltage while cruising on throttle, in gear off throttle and idle?

I noticed today that mine was as low as 12.6 volts while cruising in 5th gear on throttle. When I would let off the throttle while in gear, the voltage would jump up as high as 14.2 volts, then back down when back on the throttle. When I was stopped at idle, voltage would drop to as low as 12.1 volts.
This does not seem normal to me. Typically, the voltage should be around 14 volts during normal operation, so that the battery will charge.
Am I missing something here?

I recently fixed my car up after having misfires and bad idle after the long tube header install. Had to buy new downstream O2 sensors. Today I fixed it and it sounded so much better and was running better then the car started wanted to die on me like if it was running out of gas then it would turn off. The voltage was 14.2 for the battery. And I did a 40 mile drive to work and saw that when I would stop and the car wanted to die out the voltage would bounce up and down from 14 to 13ish. I still need to replace my upstream O2 sensors so don’t know if I should buy a new battery while I’m at it

 

[ponie1992]

I recently fixed my car up after having misfires and bad idle after the long tube header install. Had to buy new downstream O2 sensors. Today I fixed it and it sounded so much better and was running better then the car started wanted to die on me like if it was running out of gas then it would turn off. The voltage was 14.2 for the battery. And I did a 40 mile drive to work and saw that when I would stop and the car wanted to die out the voltage would bounce up and down from 14 to 13ish. I still need to replace my upstream O2 sensors so don’t know if I should buy a new battery while I’m at it

Strange symptom

 

[Emilbadal]

Hi everyone, Not to hijack the thread but I have this one question which I think is relevent enough to ask it here. Can you share what is your battery voltage is before you start the engine? The highest I’ve seen on mine is 11.4V. I’ve read that it’s supposed to be close to 12.6v but I’ve never seen it. I’m just wondering what yours read out

 

[WD Pro]

11.4 (open circuit) is pretty much flat.

If that’s still starting the car you have an inaccurate gauge reading.

Stick a volt meter directly on the terminals as a comparison / double check

WD

 

[Emilbadal]

Lol, it starts with as low as 11V. It's been like this for years. Good idea, I have to check it directly on the battery

 

[Engelhalo71]

Old post but, Yes the S550 uses regenerative charging, The PCM cuts the alternator field to help increase gas mileage under load, then starts charging under no load coasting other factors.

On another note,, My stalling issues were caused by the drivers side VCT. Unfortunately my car went to Mustang heaven after it was killed by a DUI'er.

But at least it quit stalling ...

.

What is everyone's battery voltage while cruising on throttle, in gear off throttle and idle?

I noticed today that mine was as low as 12.6 volts while cruising in 5th gear on throttle. When I would let off the throttle while in gear, the voltage would jump up as high as 14.2 volts, then back down when back on the throttle. When I was stopped at idle, voltage would drop to as low as 12.1 volts.
This does not seem normal to me. Typically, the voltage should be around 14 volts during normal operation, so that the battery will charge.
Am I missing something here?

I have a 2019 mustang premium pp1 I changed the battery had to get what ever they had for my car in stock now my voltage used to be at 14 volts always now it Fluctuates between 13.5 n 12.0 should I be worried my alternator is going bad n it sputters like it wants to shut off n the rpm rises and drops any ideas

 

[Emilbadal]

Did you do the BMS reset routine after replacing your battery? The voltage fluctuation in of itself is not a bad sign. If the fluctuations are erratic then it might be a bad sign but if they are not erratic and they stablize for a few seconds to a few minutes then it is normal. When the engine is running and it shows between 12 to 12.6 volts. It means that your battery is charged up and alternator is not charging the battery anymore. But this will change after a while and the voltage will go as high as 14.5volts because the battery is discharged enough that needs recharging. Everything is managed through BMS strategies. Your engine sputtering could have some other causes. I noticed on my car that sometimes the rpm drops when the AC compressor kicks in.

Your local autoparts store can load test your alternator and tell you if the alternator is bad or not.

 

[Nanaq]

Did you do the BMS reset routine after replacing your battery? The voltage fluctuation in of itself is not a bad sign. If the fluctuations are erratic then it might be a bad sign but if they are not erratic and they stablize for a few seconds to a few minutes then it is normal. When the engine is running and it shows between 12 to 12.6 volts. It means that your battery is charged up and alternator is not charging the battery anymore. But this will change after a while and the voltage will go as high as 14.5volts because the battery is discharged enough that needs recharging. Everything is managed through BMS strategies. Your engine sputtering could have some other causes. I noticed on my car that sometimes the rpm drops when the AC compressor kicks in.

Your local autoparts store can load test your alternator and tell you if the alternator is bad or not.

What is the bms?my gt has always shown 14v. But the battery drained. I charged it and it drained again so I put a new battery in it and it drained. Now it only shows 12.1v. Right now its sitting st a ford dealership. Been there for 3 days. Ant help

 

[Emilbadal]

What is the bms?my gt has always shown 14v. But the battery drained. I charged it and it drained again so I put a new battery in it and it drained. Now it only shows 12.1v. Right now its sitting st a ford dealership. Been there for 3 days. Ant help

BMS is Battery Management System

 

[Farkel]

What is the bms?my gt has always shown 14v. But the battery drained. I charged it and it drained again so I put a new battery in it and it drained. Now it only shows 12.1v. Right now its sitting st a ford dealership. Been there for 3 days. Ant help

https://www.mustang6g.com/forums/threads/bms-reset-no-tools-required.151602/