[Tdog02]

Today while driving into work I smelled a faint electrical odor that just seemed odd. I have a plug in voltmeter gauge and it was reading a steady 15.05 charge. It later dropped back to 13.54 but not for at least 10 minutes.

Question: is this normal operation for the battery management system? I haven't read anything about it and was hoping to avoid future problems.

FYI: I had to replace the alternator and battery back in June 2019 due to failure of the alternator at around 58k miles, I have 92,000 today.

 

[snakebitten]

I'm no wizard but I have "voltage" pid displayed full time on my Ngauge. (so it's pid driven value)

It's a dancing value. In order words, the exact value is a constantly changing value on the right side of the decimal. (example 14.34 the "34" is constantly changing within a range)

I have NEVER seen 15 left of the decimal. Ever. So whatever that was, I would consider it a concern. Much as you obviously are.

From what I understand, even though our trucks are equipped with the notorious BMS (battery management system), the alternator is still equipped with the normal voltage regulator and that regulator would limit the output of the alternator to LESS than 15V.

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[Tdog02]

It was concerning. I try to pay attention to my truck and take maintenance seriously. I can find no info on charging going that high, and I kinda have a suspicion that something in the system caused the first alternator to over charge. I remember smelling the same odor prior to that failure and was something I was never able to chase down. It only hit me as I was smelling the odor this morning.

 

[Recflyboy]

First thing I would do is test your voltmeter to see how accurate it is. If it is correct I would bet on the voltage regulator starting to crap out. Even if there is a short somewhere it should not go that high.

 

[Arkansas Eco]

Is the voltage regulator built into the alternator ?

 

[Justinjs]

Mildly related. I had my dongle hooked to my f.i.l. 2014 malibu. It was running 15v while driving as well. The car does have start/stop and only has 16k, unlikely there's anything wrong with it.
My question, does 2016 have start/stop? Could it be the BMS stuff? My father's 2020..2019...idk remember honestly, runs 12v when driving and occasionally would kick up to 14.4-ish, blame BMS?

 

[Arkansas Eco]

Some alternators will in fact output 14.4 volts, and like Snake said, always under 15, unless the regulator went haywire.

 

[N4HHE]

I have a Bluetooth battery tracker on my F-150. $30-$35 on Amazon. Logs voltages for past 30 days. Pays closer attention to starting events. Also records when vehicle is parked. Hit 14.91V today. That is not unusual for short periods. The BMS does strange things, but presumably for good reasons.

 

[Tdog02]

Is the voltage regulator built into the alternator ?

Sadly, yes.

The alternator on these trucks run over 500 USD. When mine was done in 2019, the list price was $759. My bill was right at $1500 with alt and battery replacement.


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[Tdog02]

I will be checking to see if my cheapo voltage meter is accurate and I have a different one coming.


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[N4HHE]

Sadly, yes.

The alternator on these trucks run over 500 USD. When mine was done in 2019, the list price was $759. My bill was right at $1500 with alt and battery replacement.

Its fantastic that the "voltage" regulator is built into the alternator. This is a great advancement we took 30-40 years ago. This isn't any caveman 3-terminal LM7812 regulator but one that actively controls the alternator field intensity to regulate output. Your alternator does not draw more power from the engine than necessary to meet the electrical load.

parts.ford.com lists my alternator for $606 plus $75 core. Steep, but it is a 200A alternator, not your grandfather's 60A. I remember when "Police/Taxi Specials" came with outrageous 115A alternators. "Who would ever need such a huge alternator!"

 

[GearHead_1]

Not pointing anyone in this direction but the reman AutoZone alternators rate theirs at 220 Amps and offer a lifetime warranty. I’m not suggesting this to be a better choice than an OE but at $500 it is an option.

 

[N4HHE]

Not pointing anyone in this direction but the reman AutoZone alternators rate theirs at 220 Amps and offer a lifetime warranty. I’m not suggesting this to be a better choice than an OE but at $500 it is an option.

In decades past past of the time an alternator or starter failed, a $10 set of brushes restored function.

 

[GearHead_1]

That probably hasn’t changed. The brushes wear out, the diodes go bad or the regulator gives it up or in @mwemaxxowner case the bearings throw the towel in.

 

[mwemaxxowner]

I looked mine up out of curiosity when the dealership told me it was bad, and it's $477 on Tasca. I didn't check the shipping price.

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[N4HHE]

That probably hasn’t changed. The brushes wear out, the diodes go bad or the regulator gives it up or in @mwemaxxowner case the bearings throw the towel in.

Even the bearings, diodes and regulator boards are relatively easy to purchase. If wiring burns out then the DIY is mostly SOOL.

 

[GearHead_1]

No doubt you could rebuild these for a fraction of the cost of buying one.

 

[snakebitten]

No doubt you could rebuild these for a fraction of the cost of buying one.

At 18 years old I got hired at Haliburton/Brown&Root for triple the pay I had ever made on my previous student Era jobs. And I wasn't qualified for ANY of the job openings, so I was amazed that I got hired.

For the first 6 months I rebuilt Ford alternators. The elder gentleman who trained me could train anybody at any station for any device that needed rebuilding. I have no idea where they were keeping all the vehicles/machinery that could possibly consume the endless number of the same Ford alternators that I rebuilt daily. You get to where you can do it without thinking. And eventually you reach an almost 100% QC passing of your work.

I don't know exactly what today's components would cost or if they are even available for purchase, but they aren't very complex to assemble if you just look at them.

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[mwemaxxowner]

As somebody who's an avid DIYer, and my famous line is "I can do that myself and do it cheaper", sometimes I also have to know when it's not worth it.

I'd have to spend time researching where to find the correct parts. Then I'd have to spend time going over how to do the work and do it right.

For me, I hate to admit it, I think I'd rather throw $500 at a new alternator, the swap is quick, and be back on my feet in no time.

That said, I'd be tempted to eat my core charge, save the old one, and rebuild it in my spare time to have a good spare on hand.


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[Recflyboy]

I buy written off trucks for that price and have all kinds of spare everythings