Is this a charging issue?

I just came from a 4runner and the volt gauge was always straight up. My Tundra however as you can see is always right around here. At start up, it's charges. But goes back to this point driving around. Sorry if it's a bad pic, I'm on my cell phone and the pic was taken while at highway speed.

 

That’s normal. The ECM shuts off the alternator to decrease parasitic losses if it judges that the 12V battery doesn’t need to be charged. There’s a sensor on the battery negative terminal that measures the battery charge, voltage, amperage, etc. When you’re cruising the alternator will shut off and the battery will supply 12V but when you’re slowing down/braking the alternator will kick on and charge at 14V. Also, it will charge whenever the ECM judges that the voltage is too low.

Germans have been doing this kind of thing for years now.

 

Thanks! This is the first time I've seen that and wasn't sure what was up.

 

Here’s an explanation of a similar system
https://youtu.be/8NRajpYXGb4

https://youtu.be/I-pn0VsCQyU