What is the correct battery voltage range?

[cricha]

'24 3500 SO CTD. Truck has been in the shop now 8 times for electrical issues. Thought this last time they might have fixed the issues.
Dash voltage display has started to fluctuate. Mostly indicates 14.2-14.3V running normal on the fwy and around town. Starting to see voltages of 13.6-13.8V pop up sporatically. when they do pop up, it will be for however long the truck is running (sometimes hours). The next time the truck is started, it may go right back to 14.2-14.3V, or it may not. Batteries were changed out by the dealer a few months ago, so they are basically new. The CTS I have agrees, or is within 0.1V.
No heavy electrical loads, batt cables are new and connections clean and tight.
What should I be seeing for a correct operational voltage range?

 

[Grumpy8811]

anywhere between 13.5 and 14.5 is fairly normal..
if the battery is fully charged and electrical loads are under control, nothing wrong with charging voltage being in the 13 range, as it isn't discharging..

what you are seeing on a restart is the alternator trying to put the current back into the battery that was used turning the starter motor, once that is accomplished the charging rate looks like it is reducing..

 

[AH64ID]

Voltage is based on charge rate, battery temp, and loads. Everything you’ve mentioned seems normal. The truck has a battery monitor and will reduce voltage when the battery SOC is sufficient.


What kind of electrical issues are you having?

 

[Learjet]

sounds like normal operation from what I have seen.

 

[Ozymandias]

Even up to 15.3 on a very cold morning is normal, as good as just 13.2 in 110f Nevada heat.

 

[Tuesdak]

Batteries were changed out by the dealer a few months ago, so they are basically new.

12.6V is battery voltage. Above that is charging that varies by temperature, colder = higher voltage, and what charging stage it's in. Bulk charging is the 14.4 - 15V area. Float is around 13.5V. Generally as mentioned above charging voltage is all over the place ~13-15V. This voltage range isn't your problem.

If that's the only remaining concern stop here.

X2 what problems have you been having and still are having? I am curious as to why there are "new" battery cables? Esp. as a bad battery cable could have murdered one battery and damaged the other. RAM may have replaced just one battery and sent you down the road "cheap" over another $100 battery that can cost them a Lemon Buyback. RAM's being Cheap not Frugal.

Now you just gave likely electrical PROBLEM #1 a free pass. New batteries, so what? Start troubleshooting over and NOTHING gets a free pass. Why is a brand new off the shelf battery going to be any good and not suffer a manufacturing defect? Did it sit on a shelf for 6 months going bad via self discharge prior to install? Lead acid is very easy to murder quickly so any problems can kill the batteries. You 100% positive the dealer replaced both batteries not just one strict warranty criteria bad one due to RAM's "cheap" warranty policy? You need to replace batteries in pairs as a bad battery likely murdered the good one via sulfation. Now the new battery can be hurt by the old tested good battery. Maybe you did get both replaced, but, as you (assumed) still have electrical problems you need to start troubleshooting with the batteries.

Get a voltmeter and read the voltage at the battery posts for each battery: write it down. Start the truck and record the voltages twice (just in case it switches charging voltage as you walk over to the other battery). The voltage should be the exact same past the decimal point. If not you still have a battery cable problem.

Then I suggest you disconnect the ground on one of the batteries (engine off key off of course) and then load test both of them. Make a note of their voltage before and after testing. 12.X where X after the decimal is really important. (12.6V, good, where say the other battery has 12.4V would be a problem at just 0.2V difference. I would question 0.1V myself but that's knowing I have a good quality meter.) You have to remove one ground or the good battery will hide a bad one due to the connections between them. This will make sure you have good batteries that are not causing the problems.

 

[Grumpy8811]

at the end of all this, does the original question revolve around a specific electrical problem or is it just a question looking for a problem that doesn't exist?

 

[sag2]

at the end of all this, does the original question revolve around a specific electrical problem or is it just a question looking for a problem that doesn't exist?

I agree, if the truck starts quit looking at the battery voltage. It is going to be what the ECM decides it needs to be.

 

[cricha]

at the end of all this, does the original question revolve around a specific electrical problem or is it just a question looking for a problem that doesn't exist?

Going back to the original problems, truck was in the shop 8 times for electrical issues with steering wheel/instrument cluster control switches inoperable. The last time the truck was in the shop it was because the truck lost electrical power and was dead in the water. Before ANYONE says "you musta left something on and drained the battery" I can ASSURE you beyond ANY doubt, NOTHING was left on.
The last time the truck was in the shop (because it was electrically dead) the dealer said they checked all connections and replaced BOTH batteries . They made it clear they were only replacing the batteries as a favor. When they replaced the batts, the tech severely over tightened the passenger cable lug and crushed it beyond repair. This terminal lug is NOT one of the solid ones, and requires the replacement of the cable and lug, so I requested that they replace it under warranty. they agreed. It's been OOS since then.
The dealer stated they replaced both batts, but I am not sure they did. My reason for the thread is to get a good idea of what battery voltages I should be seeing, and if there may be another issue buried somewhere.
The info I have gotten from all you guys on here (that know way more than I) has been extremely helpful. THANK YOU!!

 

[Grumpy8811]

My reason for the thread is to get a good idea of what battery voltages I should be seeing, and if there may be another issue buried somewhere.
The info I have gotten from all you guys on here (that know way more than I) has been extremely helpful. THANK YOU!!

static voltage of a fully charged lead acid battery is 12.6VDC provided any surface charge is removed..
Running voltage should be between 13.5 and 14.5 VDC but it can vary outside of that,,.