Hey guys, I am new here and not well educated in mechanics but wondering if any of your trucks fluctuate voltage when driving? I noticed my truck was running around 13.2 and the needle was bouncing from 1/2 to the bar below that. I pulled up the voltage reading on the instrument cluster and it bounces anywhere from 13.2 - 13.7. I have read it should be above 13.8 and holding steady. I thought this might be a battery issue so I replaced the battery yesterday, saw my voltage around 14.1 for a few miles and now back to bouncing from 13.2 to 13.7 when driving/idling. Could something be wrong with my alternator or is this normal?
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Voltage meter reading between 13.2 and 13.7
- Thread starter rcadams27
- Start date
I had the same issue. Replaced my battery with AGM and the problem didn’t go away. Mine would drop down to 12.6 after an hour drive. The dealer “tightened” the negative terminal or the battery sensor which seemed to fix the problem for now. They ordered a new battery sensor for install next week. The mechanic said battery and alternator/etorque system was in good shape.
HandyCruiser
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If I'm reading this right, it all sounds perfectly normal to me. I would expect that with the engine running, the voltage across the system (and across the connected batter) should be around 13.2 to 13.7 volts. With the engine off, it should be around 12.2 to 12.7 volts.
bigdodge
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do you have the etorque?
I have the bighorn standard 5.7
It’s one in the same. Even if you stick a dvom on the battery while the alternator is charging, it will match the output of the alternator.
Charging voltage is 13.6-15.6, and standing voltage depends on battery type (agm, flooded lead/acid, etc). However, newer alternators can cycle their charging, so you may not always see 13.6+ if connecting a dvom if the battery doesn’t need to be charged. I haven’t looked at RAM 1500 theory and operation of the charging system, so I don’t know how our alternators function.
E.Hands
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13.2 to 13.7 volts is normal. If you can load the system up with all your lights, AC blower on high and windshield wipers going and still maintain 13.2 volts at idle then you are experiencing normal vehicle function. Enjoy you 5th Gen!
E.Hands
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Anything over 14.4 would be cause for attention in my opinion. AGM batteries shouldn't see over 14.7 volts IMO.
Mountain Whiskey
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Anyone think that the gages are not perfect? I mean, they are really just cheap production automotive gauges. Probably one step away from an idiot light. They just might be off. I tend to read mine for consistency. If one reads way different than it has been this whole time, it might be a red flag.
I’m stating the acceptable range of charging for 12v automotive systems, so it is what it is.
Awesome, thanks for the replies, I feel a lot better about it now. I guess I just never noticed the voltage gauge on the instrument cluster bouncing around so when I noticed it I got a little worried. Just hit 35k today on the 2019, love the truck. Pulls the hell out of my 5000 LB travel trailer. Added an extended warranty today for another 125k miles just to be on the safe side since I do tow the trailer year round. Hoping to hit 200k some day!
HandyCruiser
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One of the easiest ways to check a vehicle's voltage during regular operation and then compare it to other vehicles is with one of these. Plus these will charge your phone too. If you are worried about accuracy, simply compare its readout to a calibrated multimeter. And again, what you describe is pretty well the normal range.
sppb32
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With the engine running it should be 14.3 to 14.5 volts, mine is, i have a 80 ah of lithium cells behind the back seat for the sound system, since it rests 1 volt higher than the factory battery (SLD) it gets isolated from the front battery when i shut of the ignition, i don't know how the battery monitor works but id doesn't seam to have a problem with all that stuff.
