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Weak battery or alternator?

Bdubbs

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Hey guys,

I noticed today my 19 350 when starting it the dash volts only showed 12.9 volts. It's normally at 14-14.5 volts, even when driving. I only drove it for a short time. I seen the volt gauge fluctuate from 12.5-14.4 volts. The high voltage side didn't last long at all. Towards the end of my 20 minute drive it was staying around 12.5-12.7 volts.

Once I got back to the shop I turned the AC on and the voltage jumped up to 13.3. I should have turned on all the lights but didn't.

Per Carfax, it looks like the dealership replaced the battery back in 2019. And I periodically put it on a tender. Volts on battery when I was done driving was 12.61.

No other symptoms during the drive, but curious what everyone's thoughts are.

I've only owned the car since May and it has 17,500 miles.

Thanks 👍
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Inthehighdesert

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Chance’s are its your battery. Easy enough to put a volt meter on both and check them. Three years is about normal here on my diesels for battery life. Four is about right on the gas powered stuff I have.
 

Park

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I’ve read before that we have a smart charging system ?
Voltage will vary ?
 

ice445

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I’ve read before that we have a smart charging system ?
Voltage will vary ?
Yup, BCM only runs the alternator at the needed duty cycle for the car's electrical demands to save a tiny bit of fuel/wear. If your alternator is actually underperforming it will almost always set a code. IMO its a sign that your battery isn't healthy if the car is always charging at a high voltage. Or the battery was just low. Given the tiny stock battery size on the 350 it doesn't sound like anything is out of the ordinary.
 

Demonic

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Yes, the smart charging system will vary the voltage output depending on multiple variables such as engine load or charge state of the battery. You can’t read into it if there isn’t an actual code thrown. That being said the stock batteries are only good for about 3 years.
 

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Bdubbs

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Yes, the smart charging system will vary the voltage output depending on multiple variables such as engine load or charge state of the battery. You can’t read into it if there isn’t an actual code thrown. That being said the stock batteries are only good for about 3 years.
This is some good information, I appreciate it. Is the factory battery still under the 3yr/36,000? I really don't want to bring it in for a battery. And is there a better battery option?

Maybe I'll take it out for a spin again and see what it does.
 
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Bdubbs

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Yup, BCM only runs the alternator at the needed duty cycle for the car's electrical demands to save a tiny bit of fuel/wear. If your alternator is actually underperforming it will almost always set a code. IMO its a sign that your battery isn't healthy if the car is always charging at a high voltage. Or the battery was just low. Given the tiny stock battery size on the 350 it doesn't sound like anything is out of the ordinary.
For some reason the multi quote feature didn't work for me. I appreciate the info. The last few months I've just never seen the volt gauge fluctuate like this, let alone go below 14 volts.
 

460Fred

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Kind of strange the dealership replaced the battery before selling the car. I guess it sat and they didn’t maintain it. I bought my ‘19 new in June of 2020. If they replaced the battery, it wasn’t recorded. Car had 140 miles on it.
I live in a desert climate with intense heat in the summer, deadly on batteries. Our Subaru goes through Interstate batteries every four years like clock work. My Dodge Diesel 2500 work truck, every three years.
I guess it’s time to use my Ford rewards points to get a new battery. Hopefully I can trust the local dealership to do that.
 

The Chairman

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This is some good information, I appreciate it. Is the factory battery still under the 3yr/36,000?
Yes, it is covered under warranty. My Navigator battery died one week before my 4yr/50,000 mile warranty expired and they replaced it for free.

I keep my Shelby’s on trickle chargers. The ‘09 GT500 battery lasted for 11 years and my ‘16 GT350 is going strong at 6.5 years.
 

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Hey guys,

I noticed today my 19 350 when starting it the dash volts only showed 12.9 volts. It's normally at 14-14.5 volts, even when driving. I only drove it for a short time. I seen the volt gauge fluctuate from 12.5-14.4 volts. The high voltage side didn't last long at all. Towards the end of my 20 minute drive it was staying around 12.5-12.7 volts.

Once I got back to the shop I turned the AC on and the voltage jumped up to 13.3. I should have turned on all the lights but didn't.

Per Carfax, it looks like the dealership replaced the battery back in 2019. And I periodically put it on a tender. Volts on battery when I was done driving was 12.61.

No other symptoms during the drive, but curious what everyone's thoughts are.

I've only owned the car since May and it has 17,500 miles.

Thanks 👍
Bdubbs-
Quick story on my 2020 R, regarding my battery & alternator, that was extremely dangerous and want to share so this doesn't happen to you or anyone else.

Backstory - I park the car in my bldg parking garage and wasn't able to put it on a battery tender (no wall outlets were available). Historically, last year I would always get a "Saving Battery" message on my LCD screen on shut down/start - in the winter- driving it once per week. Car was consistently driven on weekends and have about 6K+ miles on it. Some mornings it might be slow to crank but always would eventually turn over and run fine. Always sat at 12.8V (didn't realize that was low) and didn't think much more of it. This summer, I noticed fuel consumption getting worse and sometimes shifting would become more difficult but again brushed it off.

All of this culminated on the NJ Turnpike, one Sat afternoon, with a "12V Charging Fault" warning light and within about 40 seconds everything in the car shut down: first the LCD, then the lights, then the gauge clusters, then power steering and finally the car completely died. Thankfully, I had the presence of mind in that short timeframe to realize what was happening - keep my speed up - and get over to the left lane and then on the shoulder.

After about 3 hours I got towed to a local dealer (none of these tow companies have race ramps so make sure you have something in your trunk if you own an R) and a week later got warranty approval for a bad alternator + battery. The more I researched this problem, the more GT350s I find having bad alternators and batteries. Once they are replaced they seem to run fine but initially it seems to be a persistent problem. Overall, it was the scariest car situation I've ever been in. If I was in a bad spot on the turnpike- and wasn't able to get on the shoulder- I prob would have ended up in the hospital and the car totaled.

Bottom line, please make sure someone checks your alternator fully and I would replace the battery ASAP just to avoid any issues. Lessons for me - I went out and bought a battery tender + battery operated generator (to get around the wall outlet issue) for this winter. I also went to Home Depot and cut up 3ft sections of 2x6 wood (to act as race ramps) and put it in the trunk in case of future tow issues.
 

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galaxy

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It seems like every time I scroll down to look at voltage, mine is always always 12.8, LOL. Drives great, always starts, no issues. I've never seen anything on mine but high 12's. Been this way for 25K successful miles (knock on wood). I have seen 13 or slightly over on occasion if it went a few days without being on a charger. I think mine lives in the high 12's, low 13's because it's never not on a charger at home. Never thought this was cause for concern (and the way my car runs, i still don't). I just don't hardly ever monitor voltage; that helps alot also, LOL.
 

fatony618

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It seems like every time I scroll down to look at voltage, mine is always always 12.8, LOL. Drives great, always starts, no issues. I've never seen anything on mine but high 12's. Been this way for 25K successful miles (knock on wood). I have seen 13 or slightly over on occasion if it went a few days without being on a charger. I think mine lives in the high 12's, low 13's because it's never not on a charger at home. Never thought this was cause for concern (and the way my car runs, i still don't). I just don't hardly ever monitor voltage; that helps alot also, LOL.
I thought 12.8 was normal as well but once the alternator and the battery was swapped its now always 14.4. I guess each car is different.
 
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Bdubbs

Bdubbs

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It seems like every time I scroll down to look at voltage, mine is always always 12.8, LOL. Drives great, always starts, no issues. I've never seen anything on mine but high 12's. Been this way for 25K successful miles (knock on wood). I have seen 13 or slightly over on occasion if it went a few days without being on a charger. I think mine lives in the high 12's, low 13's because it's never not on a charger at home. Never thought this was cause for concern (and the way my car runs, i still don't). I just don't hardly ever monitor voltage; that helps alot also, LOL.
Maybe that's why mine was reading 14.5 for quite some time. Because I only periodically put it on a battery tender. I've only put maybe 150 miles on it since May.
 

NightmareMoon

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3yrs is the life expectancy of a Ford battery. If you’re having issues and the battery is that old, its a pretty safe bet
 

Egparson202

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My 350 has developed a slightly different set of symptoms that seem alternator/battery related. It began with intermittent display of a “Charging System Service Now” message but no other symptoms. Both the battery and the alternator got a clean bill of health from a Parts Store check. My Indie mechanic examined it and couldn’t replicate the problem.

It was good for several days. But then it returned and got much worse. The message became much more frequent, the volt meter was all over the map on the high side (14-15-16 volt readings).

Thinking that the battery on my 2019 with 11K miles was the likely culprit and being on the road 4 hours from home on a Sunday afternoon we threw a new battery on it. And we reset BMS. No change. Eventually it started shutting down systems (interior lighting, infotainment, climate control, power steering). Volt meter still jumpy and showing lots of high readings.

One quirk is that the symptoms are dramatically reduced at super slow/parking lot/stop&go speeds.

I have a Ford dealer service appointment for next week, but I’m curious if anyone here has seen this before.

At this point my thinking is either bad alternator or a bad/loose ground wire somewhere.
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