Voltage fluctuation

[securityguy]

Voltage is directly proportional to resistant (V=IR) and resistance increases with temperature due to increased vibrations of the molecules inside the conductor. Therefore voltage increases as temperature increases.

Understood...but why am I now seeing decreased voltage while driving my eT? I am not concerned at all as all voltages are within normal operating parameters, I just find it interesting.

 

[RAM Patriot]

Understood...but why am I now seeing decreased voltage while driving my eT? I am not concerned at all as all voltages are within normal operating parameters, I just find it interesting.

My understanding is your e-Torque is using your 48V lithium battery pack behind the rear seats in your cab. Lithium is also greatly affected by temperatures especially lithium-ion technology.

Our Trucks have a smart alternator on them so since your 48V battery pack is holding it's charge better in the warmer climate there is less demand on the alternator to provide juice to the pack and so the alternator runs at a lower voltage which takes less power from the engine and is suppose to increase your mileage.

 

[That_hemiguy]

So I’ve checked the digital readout and it’s running from 14.8 to 14.9v. The fluctuation is back and forth between those two numbers. Temperature outside is about 40 degrees. Is 14.9 too high?

Have you resolved this issue experiencing the same thing.

 

[securityguy]

14.9 is just fine...no issues.

 

[That_hemiguy]

14.9 is just fine...no issues.

Ok but my needle on cluster from battery is bouncing one notch up then back down consistently I don’t remember it ever doing that it has been cold here.

 

[securityguy]

Ok but my needle on cluster from battery is bouncing one notch up then back down consistently I don’t remember it ever doing that it has been cold here.

You under warranty? If so, take it in and have them look at it to give you peace of mind.

 

[That_hemiguy]

You under warranty? If so, take it in and have them look at it to give you peace of mind.

Yes and ok. Was just wondering if that was something normal to have the needle move like that?

 

[That_hemiguy]

Hey guys, something I have noticed since the temps in FL have been getting hotter over the last few weeks. In the Winter, I noticed that my VOLTAGE during driving would be between 13.9-14.3V. Checking at the battery would be 12.3-12.4V after the truck has been sitting for a week without use.

Now that it is hot, once again, here in FL, I am seeing the following:

1. My voltage while driving is now between 13.6-13.9V
2. After sitting for a week, the voltage is now around 12.6-12.7V

Therefore, my conclusion is that your voltage will fluctuate with temperature. Not understanding all of the idiosyncrasies of the ET system, I just thought some may find this interesting

I’m having the same exact issues can you help?

 

[That_hemiguy]

To be clear that is 40 degrees outside at cold start with nothing extra on but the radio. If I turn on the heat or air, the voltage goes down to 14.7 and sometimes 14.6. I even see a .1 v drop when I use the brakes too. So driving at 14.7 and hit the brakes it drops to 14.6 for a second.

Dude did you find the fix mine is doing it ?

 

[dburks123]

I have a 2019 ram 1500 5.7 l 5th gen my voltage goes as high as 15.8 volts my dealer says it's normal but my power fluctuates so bad it doesn't show on the digital gauge cuz it fluctuates so fast I don't have LED lights it's like a hyper flash but not quite that fast it seems like it's going to the ignition timing of the vehicle I rev it up it goes faster as the idle comes down it goes slower and the dealer tells me that I'm crazy basically and they won't do nothing about it and I'm at 99,950 miles it's at the dealership right now I don't even want to pick it up till they fix it cuz I know 15.8 volts is too high and I guarantee it's going to fry out the electronics at some point every once in awhile my heating and cooling system cuts out. I'm going to call it a flicker even though it's not so much a flicker because I know LED flickers but I don't have LED lights in there they're regular ones and when I'm driving down the freeway the power goes up down up down up down and I know people are going to say all that stuff the whatever that cuts out and turns off cylinders but that's not what it is because even at low speeds it doesn't even at an idle it does it when it's not in gear my question being is has anyone else have this problem and if so is there a fix for it or something I can say to the dealer to get them to address the problem before I have to pick it up cuz they're making me pay all these diagnostic fees when I know in my heart I know there's something wrong with it they say this ECU controls the voltage will then in my mind there's something wrong with the ECU if it allows my vehicle to go to 15.8 volts and yes I do have pictures

 

[kapinallinen2]

I have a 2019 ram 1500 5.7 l 5th gen my voltage goes as high as 15.8 volts my dealer says it's normal but my power fluctuates so bad it doesn't show on the digital gauge cuz it fluctuates so fast I don't have LED lights it's like a hyper flash but not quite that fast it seems like it's going to the ignition timing of the vehicle I rev it up it goes faster as the idle comes down it goes slower and the dealer tells me that I'm crazy basically and they won't do nothing about it and I'm at 99,950 miles it's at the dealership right now I don't even want to pick it up till they fix it cuz I know 15.8 volts is too high and I guarantee it's going to fry out the electronics at some point every once in awhile my heating and cooling system cuts out. I'm going to call it a flicker even though it's not so much a flicker because I know LED flickers but I don't have LED lights in there they're regular ones and when I'm driving down the freeway the power goes up down up down up down and I know people are going to say all that stuff the whatever that cuts out and turns off cylinders but that's not what it is because even at low speeds it doesn't even at an idle it does it when it's not in gear my question being is has anyone else have this problem and if so is there a fix for it or something I can say to the dealer to get them to address the problem before I have to pick it up cuz they're making me pay all these diagnostic fees when I know in my heart I know there's something wrong with it they say this ECU controls the voltage will then in my mind there's something wrong with the ECU if it allows my vehicle to go to 15.8 volts and yes I do have pictures

IIRC.
PCM sends a pulse width modulated field control signal to adjust output voltage, the alternator sense line sends a voltage feedback signal back to the PCM so that it can adjust the voltage as necessary.
If the PCM is not receiving a feedback signal, then the output should go high, there also could be a fault in the PCM.
Should not be all that difficult to trouble-shoot this?

 

[dburks123]

Right I agree it shouldn't be that hard to diagnose it's at the dealership right now and they're telling me I'm crazy and they're telling me there's nothing wrong with it although I can see the lights as I rev it up the lights flicker like it's going to the RPMs of the motor that tells me something's wrong and as you can see from the picture the voltage is high does that not seem high for voltage is my question cuz they're telling me that it's all normal and from my point of view they've replaced the alternator why did they replace the alternator cuz they obviously seen a problem and it's still doing the same thing after replacing the alternator I replace the battery and they're still saying there's nothing wrong with it when I'm driving down the road it almost hypnotizes me because of the flicker and it's not an LED flicker

 

[dburks123]

14.9 is just fine...no issues.

Is 15.9 to high? I'm having power fluctuation that almost is hypnotizing while I'm driving down the road it drops a half volt goes up a half a volt drops a half a volt goes up a half a volt about as fast as you can read this that's how fast it is it's annoying I bring it to the dealership and it seems to go to the RPMs of the engine they won't do nothing they tried replacing the alternator didn't do anything I get up to almost 16 volts at times when I hit the gas actually the voltage comes down and as I let off the voltage goes up but if I put the cruise control on it'll slowly climb to about 15.6 volts they say that's okay I'm sorry but a 12 volt battery that's going to kill it in no time and I have less than 200 miles left on my warranty I don't know what to do