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Discussion Starter #1
Hi Torrie:

I have recently been getting the "Low Battery" warning come up recently on my truck. A few time, my stereo would not work due to "low battery.

I had the dealership check it out and they said, while my battery is showing a "full charge" at this moment, the alternator is controlled by the PCM and will cut "on & off" from time to time to reduce "accessory drag" & help fuel consumption.

They said it is entirely possible for a vehicle driving "short distances" to have the alternator "cut off" and drain the battery when you have all your lights, windshield wipers, defrosters, heater & stereo on. With the PCM & Fuel Pump, this can quickly drain down the battery if the alternator is "off".

Torrie, is it possible for you to control the alternator to stay on longer and/or cut-off less? I would be willing to do this as a "winter tune" since this is when this it is most noticeable and us "Northerners" to have most of our accessories turned on.
 

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Discussion Starter #3
Well thank you. That was a bit of a surprise when I got home.

I sent you a quick question if you could take a few moments to read it.

I am definitely looking to give this a try ... using ALL my electrical ... and see if the low battery goes away!

THEN you will have "the fix"!
 
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Discussion Starter #8
Come on now I am really really boring and normal in person :D
Well, I'm a funny drunk, when I drink ... but I haven' been drunk in years. Maybe that's why my wife thinks I'm too grumpy?

Anyway, tune is running good. I'll need to create a CONFIG to show battery voltage so I can monitor it better. I wish Ford had included a Battery Volt gauge for this truck. Need some colder weather too.
 
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Discussion Starter #9
Torrie, I think you are onto something.

I am now able to display volts and so far, I am ONLY seeing 14.7 volts (normal) whenever I am driving. This includes with ALL accessories on.

When I turn the engine off, my voltage dropped to 11.7 volts (all the accessories were on) and slowly dropping. So my Voltmeter display is working perfectly and I can now monitor as I drive.

I will monitor over the next few weeks and let you know how it is performing.

So far, no LOW BATTERY condition either. I will try and see what I have to do to make that happen so I have a "yard stick". Before it was happening without even trying.
 

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Discussion Starter #11
Excellent, thank you for the update.
So far, I am ALWAYS seeing 14.7-14.9 volts for my Battery PID and I'm purposely running with every electrical accessory on (most I need to anyway).

I even see 14.7-14.9 volts when I am just idling. And in the morning darkness, the headlights look brighter.

I am waiting for a "cold morning" to see how hard the engine turns over. In the past, it didn't have to be that cold for the starter sound "strained" as if my battery was low. (I've had other vehicles that 'cranked' hard but that was when the temperature was a lot colder).
 

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Discussion Starter #13
Is it possible to control the alternator "on/off" based on Load or WOT? I was thinking that during WOT, then a person may wish to have the alternator to turn off, similar to many modern A/C units.
 

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Discussion Starter #15
Torrie ... I heard from a few others saying that when their battery was down below a certain voltage their truck wouldn't even TRY to start. The reason is the PCM and Fuel Pump need a certain minimum voltage to properly fire the Injectors when starting (along with cranking).

Is it possible that a "Low Battery" situation while the PCM programming has turned off the alternator MAY be causing the fuel pump & injectors to have insufficient voltage to properly fire. And if in WOT, maybe going lean and causing engines to grenade?
 

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I just emailed Torrie about tunes for this exact problem. Waiting to hear back from him.
 

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Now I'm thinking, could this be the reason a few people, (myself included) would get misfires at the top end in WOT?

Battery is getting taxed, and without the alternator supplementing electrical power, the voltage drops too much and coils cut out? Or maybe it's the injectors cutting out? Or both?

Just thinking out loud here.
 

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Torrie ... I heard from a few others saying that when their battery was down below a certain voltage their truck wouldn't even TRY to start. The reason is the PCM and Fuel Pump need a certain minimum voltage to properly fire the Injectors when starting (along with cranking).

Is it possible that a "Low Battery" situation while the PCM programming has turned off the alternator MAY be causing the fuel pump & injectors to have insufficient voltage to properly fire. And if in WOT, maybe going lean and causing engines to grenade?
If voltage is too low to crank the vehicle it won't start. If it won't start you can't achieve WOT. Or possibly I don't quite grasp your question.
 

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Discussion Starter #19
If voltage is too low to crank the vehicle it won't start. If it won't start you can't achieve WOT. Or possibly I don't quite grasp your question.
Torrie ... The cranking problem is when the battery/alternator are too low.

But, if your battery wasn't THAT low, and if your engine started BUT the alternator cuts out (on a non-fully charged battery) then with no alternator and WOT you may have insufficient voltage to power the fuel pump and/or injectors. And that may be causing a lean condition (at the worst time).
 
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