Voltmeter fluctuating

Hello everyone. So i just bought my tundra 4 to 5 days ago and noticed that the voltmeter on my car goes down from the center mark when driving and fluctuates sometimes when braking. Is that normal? Thank you for the help in advance

 

Mine does that. I also was wondering if it was normal. Anyone else?

 

I asked the sales person. He said its normal but ive been looking at alot of review videos and my brother owns a older tundra and it doesnt do that. I dont know if I need to give my truck to the dealership

 

Ya I feel like my 2nd gen did the same thing. But I’m sure we will get more comments on here and that should give us a better idea.

 

I believe its normal. My truck does the same thing. I have been reading about alternators and battery charging lately. In today's vehicles the alternator output is controlled by the PCM. If you put an unexpected load (ie accelerating), there is a short period in which the alternator is catching up to the load and adjusts the alternators output accordingly.

 

My 21 does the same thing, granted its not a huge fluctuation. I watch the voltage actual on my ultragage and it fluctuates from 13.7 to about 13.1, that will make it go from very slightly above the 50% mark on the instrument cluster gage to very slightly below the 50% mark. When I use my winch while idling it drops the voltage down to about 12.7 on my ultragage and at that point its more noticable on the cluster. Running the engine during winching at about 2k rpm lifts it right back up.

 

Totally normal.

And...before you ask...so is the fluctuating oil pressure based on RPMs.

Welcome to the Forum BTW! You should post pics of your truck in the new truck thread if you haven't already! Cheers!

 

Thank you. Its my first truck and learning by the day.

 

^^^ This. Totally normal.

 

Yes it is normal but seems no one has told you WHY it's happening yet, so I'll explain: its some EPA bullshit to do with the alternator. when you first start the vehicle after sitting for a while, youll notice the voltage sitting mack in the middle of the voltmeter, it is currently "charging" in this state and you wont be allowed to use the auto stop/start feature until its done. When you set off and after the battery has sufficient charge, itll drop back down to the normal 12 v mark and stay here most of the time. if you use that auto stop/start feature frequently, this drains some battery and whenever the battery decides it needs to charge while youre driving, it will do this when you brake so itll shoot up a bit past 16 volts. Youll notice this whenver you let off the gas, the alternator kicks in more and begins to charge the battery at a higher voltage until you step on the gas again or your speed goes below ~15mph. how on Gods green earth this helps at all with fuel economy is beyond me, but then again nothing the EPA does makes sense. hope this helps. these batteries are designed for the auto stop/start feature and quick recharging so they have all sorts of wacky voltage readings now, but alas, it is normal and nothing to worry about.