Possible to change the set alternator output voltage?

[XPerties]

As we know 04+ and up alternator output are controlled by the PCM but correct me if I'm wrong, wouldn't it be easy to change this during a custom tune tuning?

[Jackpine]

Originally Posted by XPerties

As we know 04+ and up alternator output are controlled by the PCM but correct me if I'm wrong, wouldn't it be easy to change this during a custom tune tuning?

If in fact, it is controlled by the PCM, I'd think you would be right. But this is the first I've heard of the PCM controlling the voltage of the alternator. Where did you learn this? It really sounds counter-intuitive to me. Voltage regulated alternators are pretty simple, and I don't see the advantage of adding another layer of complexity in the charging circuit.

Now, monitoring the alternator voltage is an entirely different matter and I'd expect the PCM to do that so that it could warn if a charging defect occurred.

- Jack

[cleatus12r]

Jack,

I was just having a discussion this morning with a friend of mine. He and his girlfriend are driving to Las Vegas right now for a vacation. The battery light on her 08 Suburban came on along with a message saying "Service Charging System". I've worked on a ton of these things before I quit working for Big Brother Motors....and yes, the charging system IS integrated into a separate module (and oftentimes PCM). It's more complicated than it has to be, but the auto manufacturers have to justify the added sticker price somehow!

Long story short, the alternator is still charging at 14.5 volts, but it is only a fail-safe mode. Typically, the battery and charging system control module will run a lower voltage if there aren't any loads running to reduce engine drag and help prevent over-charging. But internally regulated alternators have been doing a superb job of running accessories and keeping the battery "topped off" for how long now with no issues? Oh yeah...about forever.

[Jackpine]

I love it! It ain't broke, so let's fix it!

So, I guess if Bill (or you) have access to the code that controls that aspect, you guys could change it. But now, I have to come back and ask XPerties, why? And, I'm not trying to be a smart a$$ here, just trying to understand what you are trying to accomplish with a change in this feature. As far as I can tell, the system does a pretty good job of keeping the battery near a full charge state without "boiling" it.

- Jack

[XPerties]

Ive spent the last 2 months upgrading some things and recently got my second high output alternator (first one was from powerbastards and was a nightmare). I have a 270amp from Mechman and after spending weeks reading on many car audio forums I was interested in getting a stable 14.8 - 15.2 reading. This helps for many other aspects including amps/audio.

A high recommended company Ford Modules sells modules but they run around $100-$150 and I figured since the PCM is controlled the output during the tuning maybe it could be changed.

Missing Link Audio - Voltage Control Module - Battery Voltage & Charging - Mini Truckin' Magazine

[cleatus12r]

That would be a question for Bill.

[XPerties]

Ive spent the last 2 months upgrading some things and recently got my second high output alternator (first one was from powerbastards and was a nightmare). I have a 270amp from Mechman and after spending weeks reading on many car audio forums I was interested in getting a stable 14.8 - 15.2 reading. This helps for many other aspects including amps/audio.

A high recommended company Ford Modules sells modules but they run around $100-$150 and I figured since the PCM is controlled the output during the tuning maybe it could be changed.

Missing Link Audio - Voltage Control Module - Battery Voltage & Charging - Mini Truckin' Magazine


....sooooo Bill do you think this would be possible to do?

[cleatus12r]

Merged and moved. I will let Bill know to look here.