Lights dimming

[javisam376 10+ year member]

In short: I installed a 2 channel Sony 380WRMS amp connected to a subwoofer only and my lights start dimming when the subwoofer hits... new battery, new amplifier, big 3... lights still dimming....

I measure the resistance in all my grounds and they are 0.2OHMS or less... used 4awg wire for the big 3 upgrade... 120Amp alternator... got the following voltages measuring AT the amplifier:

Engine off / system down: 12.6V...

Engine on / system off: between 14.54 and 14.62 with everyting off (lights, dome light, heater, rear defroster), between 14.58 and 14.66 with everything on (except the radio)...

Engine on / system on: between 14.44 and 14.70 with low settings (gain -5, loud at mid), between 13.79 and 14.81 with gain at +3 and loudness on hi... everything else was on for both tests.... the dimming starts with the gain at 0 and loudness at medium...

could that help to track down whats wrong with my system (alternator, amp, battery, something else)???

do i need a HO alternator??? one of the reasons I got a med to small amp was to avoid throwing a lot of money in upgrading the electrical system...

any help???

thanks....

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[solidcrowd 10+ year member]

Don't think so...I ran around 1,100rms and had slight dimming with a 90amp alt.

I don't think a Sony 380watts would cause that much strain. Maybe your alt is shot and you just need to replace your existing alternator instead of an getting an H/O.

Someone correct me if I'm wrong

 

[DDSC 10+ year member]

check the subwoofer wiring again and make sure everythings wired right,