Battery Voltage on 2024 Tundra

I've noticed that when driving my battery voltage gauge shows around 12.5V. At idle it jumps up to 14V. I don't know if this is normal or not. My 2005 Tundra pretty much always shows 14V all the time when the engine is running. What is your experience with your Gen3 Tundra?

As a side note: I think the older Tundra's tended to overcharge the battery as I'm always cleaning battery acid off the top of my 2005 Tundra's battery. I use a acid indicator battery cleaner spray.

 

Mine fluctuates all the time depending on accelerator position. I have the digital cluster gauge.

 

Does it stay around 12.5V when you're cruising at a set speed?

 

It doesn't have a nominal value exactly but when I am cruising at steady speed it does not fluctuate.

 

They fluctuate all over the board according to what the computer thinks is best. Fuel economy is the goal I believe.

 

I'm still have more of my manual to read... where do you get a good reading on voltage? In my dash display, it is a digital line from like 9-19v, so I can't really tell anything. I thought it was a normal 12v system and expected like 9-15, with that scale, it just shows low.

 

Smart charging, charges when needed. Usually it charges when you’re off the throttle and coasting. Very similar to many other manufacturers.

 

Honda has been doing similar variable charge rates for years, only they don't have volt meters in the instrument cluster to alert you to that function. Just the old red idiot light that's supposed to illuminate when things aren't right.

It has to do with fuel economy/lower emissions in so far as every 1/10 MPG here, every 2/10 MPG there in engineering the end product eventually adds up. Also maintaining a more controlled battery State Of Charge percentage can actually help extend battery lifespan rather than just forcing constant 14 volts into battery without any control of battery SOC%. Battery chemistries vary, but often batteries will have a longer lifespan at average 50-70% SOC. Lower ot higher SOC%`s can eventually reduce overall lifespan. This is especially true with lithium or nickel based chemistries more so that lead acid, but I'm sure there's a target SOC range engineers are looking for.

Usually when decelerating or braking you'll see voltage rise way up as it's momentarily giving battery a "boost" using the vehicles kinetic energy while slowing down. Also on the Tundra you'll notice every so often when it senses a lower SOC it will elevate charge voltage for a period of time while disabling auto stop function.

 

I have the Analog gauges and there are 4 tick marks between 9v and 19V (so 2.5V per tick mark). Older vehicles would typically show 14v solid (half way point) when the engine is running. My new Tundra typically show around 12.5v when driving and jumps up to 14v when idle. It seems odd but I suppose it is normal.

 

I am glad this thread has been addressed. My '24 battery voltage indicator jumps all over the place while driving and it was starting to concern me. One thing I did notice (I just did a long distance drive so I was paying close attention to everything) is that at certain times the voltage stays constant at around 14V and my truck seems to run a lot smoother. It's almost as if when the voltage shows being around 12V I feel like the engine runs rougher and at those times the voltage stays at 14V the engine runs extremely smooth. Anyone else notice this?

 

Its normal and its the truck managing the battery voltage. You should normally see lower voltage when the truck is accelerating and higher voltage when decelerating/coasting. However if the system thinks the battery needs to charge it may go into constant voltage mode. There is also a periodic "refresh charge" mode that the truck will go into.

Also note turning on the headlights puts the truck into constant voltage mode.

Its hard to see what's going on without a scan tool, but its all controlled by the stop and start ECU.