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electrical system...lights dimming

Old Jan 8, 2006 | 11:38 PM
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electrical system...lights dimming

i just installed my subs/amp in my 95 camaro...its 2 alpine type e's powered my a rockford amp that only gives them 150 watts RMS each...it hits really hard, but at night when the subs are up all the way the lights dont just dim, they turn off for a fraction of a second, and all the gauges on the dashboard seem to freeze or drop a little, for example my speedometer dips a little when the bass hits. i know a lot of you are running amps way more powerful than mine, did you encounter this problem? i have a 1.5 farad cap and i was hoping that i wouldnt have to use it but the dimming seems so bad that i dont even know if this would fix it, ill install it later on this week when i have the time. maybe i need a new alternator? hopefully not since the system is pretty low power...but if so can i get a link to a good site where i can buy a new alternator if thats the case? but have any of you encountered the same problem? what did you do to fix it? thanks.

also, i replaced my car battery the other day with an everstart max, i didnt think i would need an optima or anything for this amp i have. the battery meter also seems to stay above half way at all times, even though the lights dim like crazy. during the day there are no problems whatsoever. is this safe?

Last edited by MattM450; Jan 8, 2006 at 11:43 PM.
Old Jan 9, 2006 | 07:20 AM
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Re: electrical system...lights dimming

update: after what i posted last night about my lights dimming, i get into my car today and it wont start. its not getting any power at all, no aux power, nothing. i took the fuse out of my amp cable and still nothing. we just spent $1500 on repairs for this car. anyone know what this could be???
Old Jan 9, 2006 | 09:22 AM
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Re: electrical system...lights dimming

First, stick your battery on a charger and then once it's got a charge make sure that your amp is turning OFF when you turn OFF the HU. Make sure the stereo's main fuse at the battery is pulled during charging. Then have the car's charging system checked out. Once you're back up and running again and you still have the dimming lights problem I would look into a High Ouput alternator. IMO, stiffening caps are a band-aid, a high output alt is the cure.
Old Jan 9, 2006 | 10:55 AM
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Re: electrical system...lights dimming

Originally Posted by LS1 RULZ
First, stick your battery on a charger and then once it's got a charge make sure that your amp is turning OFF when you turn OFF the HU. Make sure the stereo's main fuse at the battery is pulled during charging. Then have the car's charging system checked out. Once you're back up and running again and you still have the dimming lights problem I would look into a High Ouput alternator. IMO, stiffening caps are a band-aid, a high output alt is the cure.
so you think its like the remote wire or something? like the amps still drawing power when the battery's off? i just got a brand new battery the other day. is it possible that my alternator could be bad and not have been charging the battery last night causing it to deplete it?

and whats the best place to get a high output alternator? i have the 3.4l engine

Last edited by MattM450; Jan 9, 2006 at 11:04 AM.
Old Jan 9, 2006 | 11:58 AM
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Re: electrical system...lights dimming

If the remote turn-on lead has 12v on it even when the HU is OFF then the amp will stay ON all the time. If the power LED on your amp stays on all the time you have a wiring problem. Whether or not that alone is enough to kill your battery so quickly I don't know. Like I said, have the car checked. With AND without the stereo playing. If your alt can't keep up with the current demand from the stereo then it will never be able to also charge your battery. Once the engine is running the battery becomes part of the load on the charging system. Just like the stereo is a load on the charging system. If the alternator can't deliver enough current for the stereo, head lights, HVAC, etc. then the battery will never get charged properly. If anything the battery will be dis-charging because it's also trying to help the alternator deliver current to the rest of the car.

One source of HO alts is ExcessiveAmperage.com. You'll have to check with them for your specific engine.
Old Jan 9, 2006 | 07:03 PM
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Re: electrical system...lights dimming

Not sure if the v6 has the same alt but the z28's have a 140amp. If yours is smaller output, you might just get away with getting one for v8. When I finish my rebuild, I will be getting a 200amp unit.

I am currently pushing 800watts to 2 12" woofs and only have the lighting problem with it cranked up and at a stop while in gear.(below idle rpm's) They just dim but not cut off like what yours is doing.

I agree as above and suggest you check to make sure the amp is even powering off with the HU. If it is, I would have to believe that you have a problem with the system since you're pumping less than half what I am and having these problems.

Here are a couple 200amp units at summit.
http://store.summitracing.com/defaul...5&autoview=sku

http://store.summitracing.com/defaul...5&autoview=sku

Last edited by chuckd4more; Jan 9, 2006 at 07:06 PM.
Old Jan 10, 2006 | 07:18 AM
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Re: electrical system...lights dimming

i believe that my alternator is only 105amps...i think i have seen a few 140 amp alternators for my car online, that should be enough, right? we'll see what the problem is for real when my car goes to the shop today
Old Jan 10, 2006 | 08:27 AM
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Re: electrical system...lights dimming

The 140 amp alts were on LT1's
LS1's got the 105 amp alt.

What you need is a HO alt that has high output at idle speeds. Thats why I like the Excessive Amperage alts. The 200 amp model can put out 100 amps at idle speed. The factory 105amp alt won't hit that until it's up around 1,500 to 2,000 RPMs
Old Jan 10, 2006 | 11:44 AM
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Re: electrical system...lights dimming

Originally Posted by LS1 RULZ
The 140 amp alts were on LT1's
LS1's got the 105 amp alt.

What you need is a HO alt that has high output at idle speeds. Thats why I like the Excessive Amperage alts. The 200 amp model can put out 100 amps at idle speed. The factory 105amp alt won't hit that until it's up around 1,500 to 2,000 RPMs
sorry i forgot to mention that i have the 3.4l. i think it has the 105amp. you think i should get more than a 140amp?
Old Jan 10, 2006 | 12:32 PM
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Re: electrical system...lights dimming

Originally Posted by MattM450
sorry i forgot to mention that i have the 3.4l. i think it has the 105amp. you think i should get more than a 140amp?
What the alt max's out at isn't what you should be concerned with. It's the output at idle speeds that matters. The only time you really notice the lights dimming on loud bass hits is when the car is at idle. At a stop light for example. This is where the factory alt is at it's minimum output. Once the engine's RPM's are up, like when you are driving, the stock alt output is up around 105 amps which in most cases is plenty for an after-market stereo system. The Excessive Amperage alt can put out 100 amps at idle speed. Once the RPM's hit 900 it bumps up the output to 200 amps.

I checked the HO alts at AfterThoughtsAuto and their HO alt only puts out 50 amps at idle.
Old Jan 10, 2006 | 09:31 PM
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Re: electrical system...lights dimming

Originally Posted by LS1 RULZ
What the alt max's out at isn't what you should be concerned with. It's the output at idle speeds that matters. The only time you really notice the lights dimming on loud bass hits is when the car is at idle. At a stop light for example. This is where the factory alt is at it's minimum output. Once the engine's RPM's are up, like when you are driving, the stock alt output is up around 105 amps which in most cases is plenty for an after-market stereo system. The Excessive Amperage alt can put out 100 amps at idle speed. Once the RPM's hit 900 it bumps up the output to 200 amps.

I checked the HO alts at AfterThoughtsAuto and their HO alt only puts out 50 amps at idle.
actually, i was going like 50 the other night, and when the bass hit, my lights like completely shut off for a fraction of a second upon each hit and the gauges would all move a little. even if the volume was in like a middle range. i got this alternator tested and its working correctly... but i dont think it can support the load, however 300 watts rms is like nothing compared to the systems i have heard supported by a stock alternator in other cars...
Old Jan 11, 2006 | 01:47 AM
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Re: electrical system...lights dimming

I'm going to go against the grain, and say you have a loose connection somewhere. Check battery connections, inner fenderwall split points for positive and negative and all pertinent ground points.

Why? Because it's free, and because doing the math, I can't see why 105 amps isn't enough to keep 300 watts rms at mid volume from dimming lights.
Old Jan 11, 2006 | 05:56 AM
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Re: electrical system...lights dimming

Originally Posted by MattM450
actually, i was going like 50 the other night, and when the bass hit, my lights like completely shut off for a fraction of a second upon each hit and the gauges would all move a little.
In that case I would definitely check the tightness of all your electrical connections. If everything is tight then you need to have your charging system checked out.
Old Jan 11, 2006 | 11:56 AM
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Re: electrical system...lights dimming

Originally Posted by LS1 RULZ
In that case I would definitely check the tightness of all your electrical connections. If everything is tight then you need to have your charging system checked out.
tested the charging system and it seems fine. 14.29 volts under no load and 14.09 under load. im thinking its the battery connections since wal-mart installed my new battery for free and i know i should have done it myself anyway. i'll check that out when i get home today.
Old Jan 11, 2006 | 07:10 PM
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Re: electrical system...lights dimming

Have you still not determined whether or not your amp is wired to operate only when the head unit is on or not. This could be a factor as your amp will be drawing all the time and not only when the HU is operating. This could be a contributing factor although it sounds like you have some issues with your connections on your charging system.

LS1, just out of curiosity, what does the stock 140amp put out at idle?(compared to the 50amps from Afterthoughts and the 100amps from Excessive) I checked out the link you gave but when you have to ask for a price quote, it's usually an unpleasant suprise. The 200amp units on summit are pricey enough. I hate to think what those other people are asking.

Last edited by chuckd4more; Jan 11, 2006 at 07:13 PM.

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