What's the normal charging voltage for the G37? My 2012 shows 13.17v when driving. I'm using a tester in the cigarette lighter socket. It also says my battery is less than 12 volts with the ignition set to ON.

What's interesting is after about 15 minutes of driving, the charging voltage increased to 14.4v.

So do I just have a failing battery? It's original.

 

If you still have the original battery in a 2012 vehicle just replace it. It is going to fail on the first cold morning or when your vehicle is parked outside on a very cold day.

Telcoman

 

In a modern Nissan, the ECM can control the charging of the battery, so it is common to see the voltage go up and down whilst driving. Depends on what the ECM thinks is best for the battery.

The cig lighter socket may not be an ideal place to read voltages, if you were going to really diagnose you'd be better off connecting a DVM directly to the battery.

But, I agree, your 2012 battery is likely due for replacement any day now.

 

I replaced it with a battery from Costco. I local mechanic wanted $180 to replace it so I went ahead and did it myself. Kind of a pain but no way would I pay someone $105 to do it.