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Power dimming

2K views 25 replies 5 participants last post by  SSinstaller 
#1 ·
Hi!
Guidence and expertice needed :)
I noticed my lights dim when i play loud. After ive upgrade all and tuned with dsp.

My car: Passat 3c 1.9tdi
All led lights
140a alternator New 2 years ago
95ah AGM battery New 1.5 years ago
Big three with 50mm2 cable
Android head unit with optical output
Helix 8ch dsp mk1 with optical input
1 farad capacitator
Gz iridium 1000w in 1 ohm on 1farad cap
1 Rockford t1 12" 600rms sub
Helix a2 class a/b 150w*2 on 1farad cap.
Focal flax evo 6.5" running on helix a2.
JL Audio jx360 4ch class a/b 75w*4 not on cap
2 Focal Power 3" and tweeters running on jl audio jx360.

I run 2* 6.5 mids and 1 sub so i think my alt and battery should be enough power.
Planning to upgrade sub amp to better quality and to replace 6.5" with new focal power M series and put flax evos in back doors so then it would be 4*6.5" and 1 sub. I should be able to run that right?

Is the sub amp and helix amp to much for the 1 farad cap?
Should i keep 1 amp on cap and run rest on battery? Whitch one? Sub amp or helix amp?
Or sub amp on battery and rest of amps on cap?
I like the cap, i notice it kinda stabilizes all electronics in the car. Going on 400.000km and going Great! :D

Can i have tuned upp the signal and gains to much and dsp eq'ued down the bass so that i have low output that uses alot more power? Or does it always draw the power its needs to hit the bass notes, it just reqires more power after dsp tuned?

I also just noticed i forgot to upgrade my Ground cable from cap so its kinda thin and the weakest link in that case, can that be the cause?

Planning to go testing but its soo cold out these days xD

Sry if its abit much
Thx for help!
 
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#2 ·
Your ground can absolutely be the problem. Most just add another ground wire. Make sure the factory ground contact points are clean.

With your factory system seemingly pretty powerful (140 amp factory alt) it should handle a 1500w system with no problem. Caps are a waste of money. Their only use is voltage regulation. 😉
 
#3 ·
Yes the ground should be at least the gauge of the positive cables , it's just as important as the positive wire , the power flows through both to complete the circuit so if the ground is of a lot smaller gauge then that will be creating a lot of voltage drop on high current eg bass hits and most likely the cause of dimming.

Yep cap is a total waste of time and money , the amps are designed with enough capacitance for the peaks as long as the cabling is of the correct gauge , did you also upgrade the ground from the battery to the cars chassis.

My system is 2400w off the stock alternator 160A with a upgraded battery rated 720cca , this is good indication of peak current capability of the battery and also it's internal resistance (the lower the better) which is important for our high power audio systems to minimise the voltage drop on big current peaks also I upgraded to 0 gauge wiring for both positive and negative , including the battery negative to chassis and have no dimming.

So the 2 most important thing to minimise dimming and too make sure the amps have enough juice are the battery and the wiring.
 
#5 ·
Amazing that i have missed that i was using a little 4mm2 for the ground 😅😅
Replaced it with a 16mm2 but there was no difference..

Opened the trunk while i was playing and there i got the only halogen lamp left in the car, the little roof lamp. It was dimming like crazy, notice less on LED but very noticable

Also the Helix A2 amp seem to be pure class A and not a/b. Capable of 2*395wrms in 1ohm and 2*120-150wrms in 4ohm class A watts! It probably needs more power then the sub amp 😂

So im thinking that the 1 farad cap cant handle it so i will rewire some cables and use only sub amp on cap, 1000wrms in 1ohm to a 600wrms dvc sub wired in 1ohm in class D should be perfect for a 1 farad.

Need to buy new cables and stuff first.

Should i run a 50mm2 (1/0AWG i think) cable from the battery in front to the back to a distroblock or is 35mm2 (2AWG) enough? Fuse suggestion? :)

16mm2 (4AWG) from distroblock to amps, ussualy the largest size that fits, if 35mm2 fits helix amp or sub i probably use that
 
#8 ·
For the main cable to the back of the vehicle as it will be the longest run I would use the biggest cable I could afford also make sure you have very good terminals/contact with the battery posts as that is also another area that can give what you are describing and is also very important.

I use this to terminate at the battery https://www.bluesea.com/products/5191/MRBF_Terminal_Fuse_Block_-_30_to_300A along with this fuse https://www.bluesea.com/products/5189/MRBF_Terminal_Fuse_-_250A
Makes for a compact neat quality connection at the battery.
 
#11 ·
Ok new plan xD
Happy for the info and it helped me on the right way!
Kinda dont know where im going with this now but happy to share 😄

Went and talked to my local store.
Bought 5M 50mm2 cable with 300A fuse to run to back and some 4M of 20mm2 for amps.

i found a Nice offer for a rockford Fosgate t1500-1bd and 6 * t0d212! And a 20farad cap that is also a distro Block for 50mm2 to 3*20mm2. I can keep amp, cap and 2 subs and sell the rest and end upp att 0$.
I will be getting it in a couple if days 😃
I will be swapping current gz amp for New t1500 and 2 subs, 700rms each. In config with amp 1000w in 2ohm to 2 subs, 500 each which seems good. 84% efficancy from amp in 2 ohm, 140 to 180A power draw in 2 ohm!
2 t0d212 in a closed 70L box.
Saw a amplifier Dyno test on youtube of this amp.
Suggested fuse for amp 200A.
Suggested alternator 100A for some reason.

1farad cap out of the system.
How do i calculated Ampere power draw from a class A amp?
And and class a/b amp?

Helix class a amp 80A fuse.
80A fuse/12V=960w/2ch=480w/4ohm=120w.
120w per ch in 2ch in class eff. 0.25%.
120w*2=240w/12=20A* 0.25 eff. = 80A.
Did i do that right? Seem like a circle calc to me xD

Jl audio jx360 4ch class a/b 50A fuse.
75w*4 in 4ohm.
50A/12=600w/4ch=150w/4ohm=37.5w per ch🤔
Im doing this wrong.. Should be 75w.

300A fuse from battery to New 20F cap distro Block.
200A fuse to RF t1500-bd
80A fuse on amp helix A2
50A fuse on amp jx360 4 ch

My local store Said that since all my speakers is 4 ohm i will not be nearing the Ampere limit of the amps, how do i calculated that?

The Dyno test i saw with the t1500-1bd it can draw 180A to 280A in 1 ohm before clipping 😧
140-180A in 2 ohm.

My thougts so far, let me know if Im missing something or should think of something ☺
 
#12 ·
Electrical wiring Audio equipment Circuit component Electronic instrument Computer hardware

Ok so i did the upgrade!

Ripped everything out and layed all the cables under the mat, finally 😂

50mm2 from battery to 20f cap distroblock.
50mm2 ground for 20f cap distroblock.
20mm2 from 20f cap distroblock to all 3 amps.
20mm2/4awg was max size on all amps.

Have not installed the New subs yet, Only Replaced sub amp and removed old cap. Still just 1 12".

Tested and still got dimming..
If Dimming started at volume 23 before, it starts att 25 now, so it helped alittle but it can just be that RF sub amp is much better.

Sub sound is better and a bit more powerfull, have not dsp tuned yet.

When i push the sub now, the Helix amp goes in protect mode because of voltage drops..

Thinking 20f cap might be crap so ill test with just a distroblock instead.

What else could it be?
 
#15 ·
You can, but I'd be looking into a lithium solution. Adding an other AGM is gonna add a grip of weight and they do not charge and discharge as fast as a lithiums an other solution would be a super cap. Like 500 farad. Those will actually help with stabilizing electrical.

I don't know if I missed or not, but what kind of wire are you running. OFC? CCA?
 
#16 ·
If you haven't already I would upgrade the ground cable from the battery to the chassis to 50mm2 and make sure the chassis is a very good connection and solid , this is very very important and the first thing to do if not done already.

Also your connections to the battery need to be very good and low resistance , if they are decent make sure everything is tight on the battery terminals as that can be another cause for dimming due to a bad or loose connections.

How old is the battery , even just a few years old and it might not be able to provide the peak currents due to a higher internal resistance , with AGM batteries their internal resistance increases with age ,even if it's a few years old I would replace it , mine is only rated for 760cca and has no problems or dimming with 2400w peak power , I fitted it new when I installed my system.
I would be replacing your original AGM before adding another one.

Get rid of the capacitor and just get a real distribution block.
 
#20 ·
If you haven't already I would upgrade the ground cable from the battery to the chassis to 50mm2 and make sure the chassis is a very good connection and solid , this is very very important and the first thing to do if not done already.

Also your connections to the battery need to be very good and low resistance , if they are decent make sure everything is tight on the battery terminals as that can be another cause for dimming due to a bad or loose connections.

How old is the battery , even just a few years old and it might not be able to provide the peak currents due to a higher internal resistance , with AGM batteries their internal resistance increases with age ,even if it's a few years old I would replace it , mine is only rated for 760cca and has no problems or dimming with 2400w peak power , I fitted it new when I installed my system.
I would be replacing your original AGM before adding another one.

Ok thx ☺

Yes i have upgraded the big 3 with 50mm2 and made New better ground for the battery 🙂
Good strong connections, Rockford battery connector.

AGM is 2 year and 2 months old, i got 4 year warranty on it 👍 so maybe ill Replaced it.

Cap out. New distroblock inn 👌👌😁
 
#21 ·
Well fck me then 😅

Thats the wires they gave me yes.. 50mm2 and 20mm2

Whats the max CCA can handle in counter to OFC

OFC is hard copper? It will be hard to bend? Thats what i got for my big 3 earlier. From cheap store that has it all. Good stuff sometimes thought.

Thought ill buy it from car audio store this time and thats what i got 😂

But im getting to think its the Alternator not producing enough. 140A

I think i pull alot when i listen to music

80A class A
50/60 A class a/b
80-200A class b/d

Half Ampere would be 40+30+40 = 110A

I listen to music as loud as i can with quality and would think i must atleast be using half of all my amps, got 2 sets of 3-way so they must need power 😅

Found an Alt with 180A and another with 370A.

Maybe start there and all OFC wire and without caps
 
#22 ·
Start with OFC wire. That will be your issue. Don't worry about other batteries and alternators yet. Get the wire sorted out first. CCA is no good. Go on YouTube then search "OFC VS CCA" there will be plenty of videos that will explain it better than my mansplaning.
 
#23 ·
OFC will be reasonably flexible as it's made of many smaller copper wires.

Wow CCA cable is not common here in Australia , I had to go look it up as I had never come across it before , most suppliers here for 0 gauge is OFC.

Dimming will have nothing to do with your alternator as it doesn't supply the high current peaks on bass hits , that is what your battery does , that's why the battery is so important with a high powered audio system , the alternator is purely to keep the battery fully charged , if your battery is going flat while you drive then you would need to upgrade your alternator.
 
#25 ·
ok some update..

after acouple of days with testing the dimming was less and less, almost gone..

then i replaced the 1 old versions RF t1 12" 600rms (running @ 1ohm) with 2 new(ish) versions RF t0 12" 700rms each, total 1400wrms running at 2ohm from amp.

after that upgrade all dimming is bassicly gone even if i listen to WAY WAY much louder then before

how?
did the 20f cap need days to charge?
different when running subs at a 2ohm load instead of 1ohm load?
less effiancy at 1 ohm but still should pull more amps with 2 subs in 2 ohm

im really confused and happy at the same time xD
problem solved i guess
 
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