High voltage

[That_hemiguy]

So I’m having an issue I think. So it has been colder here when I start the truck my battery voltage is between 14.8 14.9 when it hits 14.9 the needle on gauge cluster jumps up one notch then back down to 14.8. After driving about a hour it goes back to 14.6 - 14.7. My question is it normal for it to be that high at first? It’s been about 7-30 degrees this week. I had battery and alternator tested and was fine thank you. 2021 ram 1500 5.7 non etourqe.

 

[SD Rebel]

So I’m having an issue I think. So it has been colder here when I start the truck my battery voltage is between 14.8 14.9 when it hits 14.9 the needle on gauge cluster jumps up one notch then back down to 14.8. After driving about a hour it goes back to 14.6 - 14.7. My question is it normal for it to be that high at first? It’s been about 7-30 degrees this week. I had battery and alternator tested and was fine thank you. 2021 ram 1500 5.7 non etourqe.

14.9v is the typical high of normal range an alternator will operate in, usually if it detects a low battery. When it drops voltage to about 14.5v, that is about a 50% capacity, around 14.2v at 80% and 13.9v full battery. This is for non-E-Torque. The questions for me is less about your alternator and more about your battery condition.

Check your battery resting voltage with a voltmeter, best about 10 minutes after a load. This includes opening the door, as that causes a drain from the interior lights and reactivates modules. So after you unlock the truck, unlatch the hood and close the door. Wait 10 minutes (without opening the door again) and check the voltage at the terminals.

It could be your battery is the issue, if so, before you buy a new one, consider one of those cheap $30 smart chargers with repair mode. Saved me hundreds of dollars reconditioning old and messed up batteries with the smart repair chargers. Just remember if you use repair mode, make sure the battery isn't connected to the vehicle.

 

[That_hemiguy]

14.9v is the typical high of normal range an alternator will operate in, usually if it detects a low battery. When it drops voltage to about 14.5v, that is about a 50% capacity, around 14.2v at 80% and 13.9v full battery. This is for non-E-Torque. The questions for me is less about your alternator and more about your battery condition.

Check your battery resting voltage with a voltmeter, best about 10 minutes after a load. This includes opening the door, as that causes a drain from the interior lights and reactivates modules. So after you unlock the truck, unlatch the hood and close the door. Wait 10 minutes (without opening the door again) and check the voltage at the terminals.

It could be your battery is the issue, if so, before you buy a new one, consider one of those cheap $30 smart chargers with repair mode. Saved me hundreds of dollars reconditioning old and messed up batteries with the smart repair chargers. Just remember if you use repair mode, make sure the battery isn't connected to the vehicle.

I have a brand new battery already.

 

[SD Rebel]

I have a brand new battery already.

You have a new fully charged battery and it's charging at 14.9v right away?

 

[That_hemiguy]

You have a new fully charged battery and it's charging at 14.9v right away?

Yes then after about a hour of driving it goes to between 14.4-14.7 and stays there.

 

[SD Rebel]

Yes then after about a hour of driving it goes to between 14.4-14.7 and stays there.

Gotcha, yeah I'm not sure I've never seen one go that high on the nearly fully charged battery.