Lights Dimming when bass hits...

[AverageGuy]

Hello all, I have been reading the forums for awhile, but this is my first post, so be easy on me.

This is my setup.

Just installed new Mechman 270a alternator.

1/0 Gauge OFC wire from alternator + to Batt +

1/0 Guage OFC wire from mounting point on Alt to Batt -

1/0 Gauge OFC wire from chassis to Batt -

I kept old existing connections intact

1/0 Gauge (not sure if it is OFC or CCA) going through 250a circuit breaker up front to back of truck (about 16-17feet) connected to fuse block then split off to Massive Audio N4 amp using about 1 foot of 4 Gauge wire.

1/0 Gauge same as above wire from ground block to chassis (about 1ft)

4 Guage wire from above ground block to same N4 amp

I am using 1 12" QC122 subwoofer wired to a 1ohm load on the N4 amp.

I am using a single (new) interstate MTP-65 battery up front.

This is my issue:

When the bass hits, my lights dim, but the cigarrete lighter voltage gauge (I know not he best) doesn't show any voltage drop.

This is regardless of engine RPM (I have held gas peddle down to bring up RPMs)

Does anyone have any thoughts or ideas that I can trouble shoot, or is this to be expected?

Thanks!

[Kyblack76]

Cheers And welcome.

Seems like your on a decent path.

Possibly just need more bank/reserve eh??..

Where is your voltage at??.. Starting & hammering?

Again, welcome...

[dereileak]

is your alternator internally regulated? cause if it is, then it could be that the regulator is not quick enough to keep the voltage up when the bass hits, cause it isnt expecting a load, try a song that plays a constant bass note and see if the voltage drops, that will give time for the regulator to jump the voltage up, mine is like that, I hate internally regulated alts, and mechman hasnt made a module where I can control the voltage yet, wish they would, cause I would buy it right away...... my new mechman does't seem like it helps any more then the stock alt honestly, and its 140 amps more at max, and like 3x the stock at idle, suppost to anyways, I havn't clamped it yet, perhaps I will, but agian I hate internally regulated alts, they are slow, and never bring the voltage up to 14.4 very often

[AverageGuy]

Thanks for the quick reply.

I should have included that information.

voltage seems to hang right around 14.2 the whole time. If I am at complete idle, I sit around 13.2-13.7 (my truck seems to idle very low, around 625-660. This is why I brought the engine RPM up, so as to eliminate that as the reason.

I am open to all suggestions, after all I am human, and could have made a mistake somewhere along the line.

Thanks!

[AverageGuy]

I would guess it is internally regulated as I have not installed anything that would allow external control, unless the truck PCM does that.

And I also thought that could be the reason (regulator not fast enough) but I wasn't sure if it was to be expected or if I had done something wrong.

[dereileak]

I would guess it is internally regulated as I have not installed anything that would allow external control, unless the truck PCM does that.

And I also thought that could be the reason (regulator not fast enough) but I wasn't sure if it was to be expected or if I had done something wrong.

well there could be lots of reasons, one in part is that power is flowing to where it wants it, and the amps will pull a lot of the power towards it, but I think it has to do with the alts regulator, the same as mine, if I play constant bass notes within the power limits of my alt, the lights wont dim, but if I have bass hitting fast, and punchy, they will dim no matter what, but its turned up decently loud, probably like 3/4 the way, and on full tilt mine drops to 11.4 ish at the lowest, but hey im only running a 220 amp alt, the biggest I can get, and I have a setup that wants around 450 amps of power, ha ha