Brief voltage drops - New alternator vs. 2nd battery vs. upgrading to 0 gauge?

[hari-bhari 10+ year member]

I had another thread asking whether or not my 130A alternator was sufficient, but I think the title of this thread will be more appropriate for my question, as well as help others.

Here's my setup:

1) MB Quart DSC4125 amp (600w RMS) for speakers

2) BA GT-24 2-channel (700w RMS) pushing an D4 IDQ running at 2ohms.

3) NEW Optima yellow top battery, Resting voltage = 12.8V

4) 4awg wiring from battery to trunk (fused at 75A near battery), then 4awg to each amp via distro block

5) Big 3 upgrade with 4awg wire

6) 130A alternator, charges around 14.1 when car is cold, 13.8 when car is hot

7) Triple checked all my ground points, they are good

When I have tight bass hits, like kick drums, I get a very brief voltage drop to the mid 12s, enough to cause dimming of my headlights and my reverse glow gauges. However, long sustained bass hits (like on dubstep), the voltage drops briefly but then comes back up and is sustained at 13.3-13.4, which is fine.

Interestingly, even when I do things like roll up my windows, I get brief dimming of the headlights, and my car has been doing this forever (even with the original 60A alternator, with the new 130A alternator, and even my LAST solara did the same thing, must be a design flaw).

Since my main power line is fused at 75A, I know the amps are not drawing more than the alternator can supply, and this is also evident by the fact that the voltage is stable with long bass notes (>2-3 seconds). So my guess is that what I really need is a buffer for that extra current draw in the form of a second battery. Is upgrading all my wiring to 0awg really necessary? All the parts and wire was around $100 but I can return it since its unopened. Or is the fundamental problem here that I need a new alternator?

Please let me know what you guys think. Thanks.

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[ahole-ic]

Here is a comparison of why your question is of faulty premise. Your voltage drop = you're stranded in the middle of the ocean.

Knowing how to swim vs Lifejacket vs Having arms.

 

[Falcons 5,000+ posts]

Here is a comparison of why your question is of faulty premise. Your voltage drop = you're stranded in the middle of the ocean.Knowing how to swim vs Lifejacket vs Having arms.

this. if you wanna do it right and not have to mess with it again, learn how to swim, get a lifejacket, and go to a stem cell center and get some arms. lol in lamens terms get a ho alt, big three, and a beefy battery.

 

[hari-bhari 10+ year member]

thanks for your responses. however, based on what i've been reading on other threads, 1300W RMS should be easily handled by a 130A alternator + a good battery. my question is, will a second battery in the trunk help provide a buffer for those brief voltage drops, or is it just going to put more strain on the alternator to charge up two batteries?

 

[sacsking916 5,000+ posts]

thanks for your responses. however, based on what i've been reading on other threads, 1300W RMS should be easily handled by a 130A alternator + a good battery. my question is, will a second battery in the trunk help provide a buffer for those brief voltage drops, or is it just going to put more strain on the alternator to charge up two batteries?

it will do just that. act as a buffer, but not the solution.

 

[TheUnderFighter 10+ year member]

As I said in the last thread, your set-up should be more than sufficient... I am at around 1600w with my system right now, on ****** stock alt, and OEM battery, with the big 3 done in 1/0. And I am fine. On bass tracks with volume up loud, I get some dimming of the headlights, nothing major, but still noticeable. However, on regular music with volume up at 30 of 35, My voltage will go from 14.2 down to 13.6, maybe 13.4 at times, but always bouncing back to 14.2 That's at idle. So how BAD is your dimming really? Is it noticeable, or is it actually really bad? Cus I know that people even have HO alts and still see SOME dimming, it's common.

However every car I've ever owned or driven, has always shown minor dimming with the windows rolling up or down. I've always thought that rather standard.

I would do your Big 3 in 1/0 (which cost me $35, not sure how you're spending $100), and go from there. The BIG 3 may just solve it for you. Maybe you will need an extra bat in the back still. And I think that if the 4 gauge is true OFC wire, that should be sufficient for a run to the distro block. Though a 2 gauge wire may be ideal, and 1/0 would be more than enough, with room to grow.

 

[hari-bhari 10+ year member]

thanks for the tips. i completed my big 3 with 0 gauge cadence cca (i thought it was ofc but its not). i also ran 0 gauge to the trunk to be split via the distro block into 4 gauge to the amps. only thing thats remaining is upgrading my trunk ground to 0 gauge, but im waiting on some more wire. i think ive seen some improvement, my resting voltage when the car is cold is 14.1, and once the car warms up its around 13.5 with the a/c on. the worst drops im getting are to around the mid 12s, but usually it stays above 13. the headlight dimming is not very noticeable, but i think my reverse glow gauges are exquisitely sensitive to voltage changes (i think there is some type of inverter that boosts the voltage very high at a low current), so its more of an annoyance. i think i can get either a 2-3 farad capacitor for the trunk, or a tiny one for the gauges to solve this problem. like i said, my voltage stays steady during loud, long (2-3s) sustained bass notes. its the burps from kick drums and such that cause the brief dips. so i think a cap would help solve this problem and would be cheaper and weigh less than a second battery.

 

[Vossy 10+ year member]

:facepalm:

 

[kramer_212 10+ year member]

if any thing add a small agm battery in the back, or a cap-cell i know that the sound stream 400 amp cap cells can be found on eBay for about $120 shipped, or what i used to have and worked great was the 600 amp kinetic battery think those are around 100 shipped to.

 

[TheUnderFighter 10+ year member]

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