hummers dimming lights

Hey people, I recently put a Lanzar opti-500X2 amp in my friends hummer and when playing the tunes pretty loud the interior lights dimmed to the bass hits. The subs are dual 10" Kaption CL's @ 2 ohms each. I was wondering if the dual stock batteries/ alternator may not be enough? I have 1/0gauge wire run to the amp. I see most people do not recommend the use of Caps anymore. Any help?

Perry Babin

Paid Member
2003-11-20 11:01 am
If, on long bass notes, the lights dim then recover before the end of the note, the problem is likely regulator lag and there isn't much you can do stop it. This is generally a situation where the alternator can produce enough current but doesn't react quickly enough to stop the initial dimming.

If the lights dim and stay dim until the end of the bass note, the alternator can't produce enough current.

Depending on how bad the problem is, additional batteries can reduce the dimming but won't solve the problem if the alternator can't keep up with demand.

When the alternator is working normally and there isn't excessive current draw, the output will be approximately 13.8v for most vehicles. When the current draw exceeds what the alternator can produce, the voltage drops and the batteries do nothing (significant) until the voltage gets to approximately 12.5v. At ~12.5v, they begin to contribute more current and as the voltage drops below that point, they continue to supply more current. The drop from 13.8 to 12.5 is going to cause incandescent headlamps to dim. Since the batteries won't do much until the voltage gets to ~12.5v, the lights will continue to dim.

There are other solutions but none are inexpensive.