Voltage Gauge Low?

I have a 2010 Tundra Double Cab. I do have an aftermarket stereo now and I believe something is going on with my voltage now.

Occasionally, if I crank my system up the voltage gauge will lower and bounce around slightly and my amp will protect until the voltage goes up.

I haven’t had time to use the dmm but I will once I get off work today. Just decided to post this because my some feedback will help.

Where should the voltage be with the stock electrical system with the truck running at idle?

 

That volt rating is within the normal range for Toyotas. Typically 14 volts is dead center and anything from about 13.5-14.5 is pretty normal at idle. Once you start drawing a lot of current the voltage could drop a bit... running your A/C pump, lights, accessories, etc could drop it down towards 12 volts at idle possibly.

The more accessories you run, the harder your alternator has to work to maintain a reasonable voltage for normal operation plus accessories. If it ever sinks towards the 9 mark or rises towards the 19 mark with normal driving then you would know you have an issue with the alternator or charging system in your Tundra.

If I have my A/C running and all my lights on and I turn on my two 100w off-road lights, I can see the voltmeter tick down for a second and then rise again
Its pretty normal, just remember the alternator spins slower at idle so its normal for voltage to be a bit lower then, versus when your flying down the highway going 70mph