2017 Yukon - Blinking headlights, but alternator and 2 batteries working fine

[Halas Empire]

Greetings, I’ve done a complete audio system change, all speakers are RF power series and added, (2) 400 watt amps and (1) 750 watt amp. I added a second battery to the available spot under the hood. And replaced the head unit with a Sony, and added 26 speakers if you count the tweeters inside all the speakers. After 2 weeks, my headlights started to blink but only at 35 volume, the Sony goes up to 50. When the headlights blink, the volt indicator is still on a solid 14 volts, it will come down a little to 12 volts but only after a long trip and play above 35 volume setting for 60 minutes.

I’ve gone twice to different shops to test the alternator and both batteries and they show they are working good. In the day, when no headlights are on, no power fading from interior lights.

I suggested to the audio shop we add a 3rd battery or I may need a competition alternator, I’ve seen 400-500 amp ones online, seems like the standard Yukon ones are around 150-170. One shop, suggests a battery bank hooked to the amps.

Any thoughts, thanks

 

[swathdiver]

The flickering lights are usually signs of a weak battery. Your amperage load when playing music is probably drawing the batteries down and the alternator takes more time than normal to recharge them. I would look into those Mechman I think they're called alternators. Lots of guys on here have them and know more than I about them.

Remember, batteries ought to be replaced in pairs. The older/weaker battery always draws down the stronger one.

@Doubeleive

 

[Doubeleive]

sounds like the alternator is under rated for your system, probably need to double the output
a fresh set of battery's wouldn't hurt either.
this is just what happens when you up the voltage draw on a vehicle, be it audio, lighting, ham, tv's, whatever.
and the bottom line is it just takes money.

 

[Joseph Garcia]

1500 total watts is not all that much, particularly when you are having issues with the volume at only 70% of maximum. Did you use #2 or #0 gauge heavy cable for the power feed directly from the battery to the amplifiers and the same heavy gauge cable for the amplifier grounds to the chassis? Too light a gauge power wire will restrict the instantaneous amperage pulses when the amplifiers draw power (like for bass sounds). Many folks also change out the cable from the alternator to the battery with the same heavy gauge power wire. This is known as the Big 3 Wiring Upgrade. If you don't have this heavy gauge cable already installed, please upgrade and get back to us with the results.

 

[Halas Empire]

Thanks for all the detailed info, I will check on the cable gauge with the installer.

 

[Doubeleive]

Thanks for all the detailed info, I will check on the cable gauge with the installer.

"After 2 weeks, my headlights started to blink but only at 35 volume"
this tells me weak battery and poor charging system, been down this road before..........