17 replies to this topic

[[TUFEA-6]]

Hey All,

Im faily new to the big stereo department, but i have a question, the setup in my car is:
Kenwood H/U
Jaycar Kevlar Splits Front
Jaycar Kevlar Splits Rear
2 x Kicker 12" Comp VR
Response 4 x 50 (for splits)
Response 4 x 100 (running at 2 x 300 for the subs)

when i crank the volume and have a fair bit of bass my volt guage in my car dies to 11volts and i have huge light dimming going on, az i turn the volume down the volt guage goes back up. (this is with the car running by the way). And if i turn it up a fair bit with the car not running the stereo turns off.

Is the problem just my stereo drains to much power for the alternator and battery to keep up with,

and will a capacitor fix this at all

[mack202]

please give more info on your system, like what size wire are you using
btw a post like this should go in the begginer section but it doesn't matter

[[TUFEA-6]]

im running 2 guage wire from battery to a fuse in the engine bay, it then runs to a distribution block in the boot which splits into 1 4 guage wire for the bigger amp and a 8 guage wire for the smaller amp, the fuse in the engine bay is 160amp i think, and the 2 in the block in the boot or either 60 or 80 i cant remember

the problem has only occured since i started running the amp for the subs at 2 x 300 rather than 2 x 200

[stazed]

Simple solution:
Get a bigger battery. You will stop seeing the problems. If you still experience them (to a much smaller degree, mind you), get your alternator re-wound to produce more current with which to charge your battery, and indirectly cope with bass hits as they come along.




Extended explanation:
The basic problem is that a capacitor is not a recommended upgrade until you've exhausted your options in the engine bay.

From the sounds of it, on bass hits your amplifiers are trying to "pull" more amps than your alternator can supply. Thus, voltage will drop from the 13.8V that your alternator puts out, to the voltage of your battery.

Now if you haven't upgraded your battery, then it is probably going to be a fairly poor performer, and when the bass hit comes through, it isn't fully charged (blame your alternator for that), so basically, your battery can't even put out it's rated 12V, hence the 11V number you might be seeing.

Here is the (usual) list of fixes (in the order you should do them!):
*Upgraded, heavy duty, deep cycle battery (Optima, Odyssey)
*Bigger alternator

Now, a standard sort of battery you would get would be one like the Optima D34 - it takes a big load, it can run at high load for about an hour with your system going full out, engine off, it can be completely discharged and recharged without negative side effects, it holds charge for very very long periods of time, etc, etc.

If you're still seeing big voltage drop, get your alternator rewound.


Hope that helps!

[[TUFEA-6]]

thanks for the help stazzed, i had the alternator rebuilt last week (unrelated problem), and just finished the stereo today, the battery is only about 3 weeks old but its just a normal heavy duty $90 battery, i will look into the optima's (where about would i look for them and what should i expect to pay)

[[TUFEA-6]]

yeah changing the ground leads was one thing on my 2 do list, what about gold terminals would they help at all

[mack202]

'[TUFEA-6 said:

']thanks for the help stazzed, i had the alternator rebuilt last week (unrelated problem), and just finished the stereo today, the battery is only about 3 weeks old but its just a normal heavy duty $90 battery, i will look into the optima's (where about would i look for them and what should i expect to pay)

don't misspell stazed's name, he goes all weird and starts twitching. haha

hmm im running almost as much gear as you (simmilar power ratings), i have an older car and only 4 guage wiring.

There must be some sort of problem somewhere. Maybe they did a shonky job when they re-built the alternator? maybe get it checked by another car mechanic.
I suppose you battery could be on its last legs too, have you refilled it with water?
Maybe you have a slightly bad connection somewhere. You could consider re-grounding the battereis factory ground maybe?

'[TUFEA-6 said:

']yeah changing the ground leads was one thing on my 2 do list, what about gold terminals would they help at all

cool someone already told you.
ummm no i wouldn't waste money on gold terminals personally, i use cheap jaycar ring terminals and i have no problems with voltage drops :roll:

[[TUFEA-6]]

if its causing huge light dim then its something on the battery/alternator end is it?? so it couldnt be a bad ground on the amp or n e thing

its really weird how it never used to dim lights at all untill i changed the way the subs are hooked up

[stazed]

Audio Express said:

do that first.

if the alternator has been redone then leave it alone.

a CAP is a patch to a bigger problem.

oops yeh this is correct!

I forgot that some people don't know that the ground wire needs to be as big or bigger than your amp power wiring!


And TUFEA, you're drawing more POWER, which is more load on the power supply, and thus you will notice restrictions in your power supply! Restrictions include inadequate wiring size, battery too small, alternator too weak.

[[TUFEA-6]]

so should be:
replacing the battery to ground leads with 2 gauge & new terminal (the stock ones wont take 2 gauge)
getting a deep cycle battery like an optima
or get alternator checked by someone else

and NO Cap Yet!!!

[stazed]

Sounds like you have a plan!

Make sure you grind back the metal where the bolt that the ground wire attaches to will secure to the car. (what a mouthful!)

[[TUFEA-6]]

ok thanks heaps for the help guys, hopefully i get it sorted then the next step is the db drags at easternats for me