Dimming issues w/ aftermarket system

[SolemnSinner]

I'm fairly well-versed when it comes to mobile audio, yet this issue has me stumped. Maybe some other folks can help me out here.

I am running an aftermarket amp/sub combo using the factory h/u.
I installed an LC2i line output converter.
I am running an AQ1200d(yes, I bought it before they changed their name to SoundQubed).
1200 watts rms @ 1ohm to a single 12" SSA Icon(1250rms) in a vented enclosure tuned to 32hz.
4 gauge wiring.
I also installed a Stinger voltage meter on my dash, connected directly to the amplifier to watch for any dangerous voltage drops @ the amp.

So here is my issue: The Stingers reading is holding steady @ 14.5 volts. On heavy bass notes it drops down to 14.2. Yet I am still getting dimming lights!

So, I took my DMM, kept the bass thumping, and went to the amp. The DMM read 14.2 with heavy bass notes.

Then I went directly under the hood to the battery. The DMM read 14.2 with heavy bass notes.

So I am perplexed as to why I have ANY dimming issues.

I checked all the grounds. They were good, clean and tight.

Do I really need to buy a 16v battery for under the hood to run 1200 watts? lol

Anybody have any ideas?

 

[sonic007]

You may have 14.2 volts but if you dont have enough current to sustain multiple loads you will get dimming. Did u try testing for current draw?

 

[ftwphoto]

You need to install a capacitor to prevent headlights from dimming. When your sub hits it takes considerable more power then everything else in the system, so especially when you have a bass heavy song, your bass draws repeatedly from the battery and the battery can't catch up in a sustained pool of available energy.

A capacitor acts like a large energy tank that the bass draws from first, and can refill much quicker, thus negating headlight dimming. I've run capacitors on my audio setups for 8 years and I've never had a headlight dim.

 

[sonic007]

Or run HIDs lol. The wont dim. You can also do the "big 3". At least upgrade the ground at the battery.

 

[Maddmatts]

The changes in voltage might be too quick for your DMM to keep up with. Most update at 2-3 times a second to make them readable. Try an analog voltage meter if you have one. It might not be any more accurate, but the needle movement will give a better idea as to how strong/sudden the drops are.

 

[SolemnSinner]

Thanks for the replies. I've done the big three(even though I didn't think it would be necessary for 1200 watts). I failed to mention that in the OP.

At any rate, the issue appears to be with the stock battery.
After driving the car around with a couple accessories running the voltage dropped down to around 12.5. That simply isn't enough.
Capacitors are a gimmick. They actually put more strain on the charging system.
So I'm going to upgrade the stock battery to a XS or Kinetik with an ultra low ESR and around 80ah. I really do not want to run two batteries with an isolator, or a H/O alternator for(what I consider to be) a paltry 1200 watt system.
I had a CRX where I was pushing 3200 wrms to 4 Sundown Sa-10's and had to do all that electrical upgrading, running 1/0 Tsunami cable throughout, H/O alt, two batteries etc etc.
This is not something I think I would need to do with the Sonic for 1200 wrms.
However being that the RS is so heavily accessorized, the 100 amp stock alt is already pushed to it's limits without having any added a/m accessories. Adding a beefy mobile audio specific battery under the hood should do the trick as it will put less strain on the charging system.

I'm thinking the HC1800 should do the trick and is only a couple hundred bucks. Not a fan of Optima's but I think even a yellow top would suffice.

In the end, if I end up having to do a bunch of electrical upgrading, I will most definitely be putting in a much more powerful system. lol

Thanks for your input.

 

[sonic007]

12.4 with the vehicle running??

 

[SolemnSinner]

12.4 with the vehicle running??

On initial startup, it read 14.5 @ high warmup idle.
Once it warmed up it dropped to the 13.5 volt range.(normal)
Started driving it around, turned on a few accessories(lights, a/c) and then started bumping the system. Voltage dropped to 12.5 on the burps.

Quite typical readings for stock electrical. But not so low that a nice beefy mobile audio battery wouldn't fix.

 

[sonic007]

12.5 is usually a standby voltage. Car off. Not car running. Thats usually 13.4ish to 14.4. I would upgrade grounds for sure.

 

[Blue hedgehog]

Yes, a capacitor will increase the load on the alternator while its charging back up from the base hits, so will adding another battery. No matter how you look at it adding extra electrical accessories will put extra load on the battery. Adding another power storage device prevents the battery/alternator from having to supply as much power during those base hits. Think of it as waves in voltage. With the cap the waves will be much smoother. Adding another battery will do essentially the same thing only the battery can't recharge nearly as quick. If you start playing high base music for extended periods you will eventually get the waves back with another battery. A large cap can be recharged between hits where a battery can't.

 

[SolemnSinner]

12.5 is usually a standby voltage. Car off. Not car running. Thats usually 13.4ish to 14.4. I would upgrade grounds for sure.

Yes, it reads 12.5 with the key in the "on" position(not running).
13.5 after warmup and DRL's on.
But once the bass starts hitting it drops to the 12.5 range, and of course rises back up to the 13.5 in between bass hits.
I also think I may need to do a little fine tuning on the calibration of the voltmeter.

btw, this is playing Gucci Mane which people who are familiar with his music, know that there is very heavy, long drawn out bass notes. 12.5 is the lowest I've seen the voltmeter go on his music.

If I were playing some of my Slayer, I'm sure the voltage drop wouldn't be as extreme.

 

[SolemnSinner]

Yes, a capacitor will increase the load on the alternator while its charging back up from the base hits, so will adding another battery. No matter how you look at it adding extra electrical accessories will put extra load on the battery. Adding another power storage device prevents the battery/alternator from having to supply as much power during those base hits. Think of it as waves in voltage. With the cap the waves will be much smoother. Adding another battery will do essentially the same thing only the battery can't recharge nearly as quick. If you start playing high base music for extended periods you will eventually get the waves back with another battery. A large cap can be recharged between hits where a battery can't.

I'm not adding another battery. I'm replacing the stock battery with a much more powerful, mobile audio battery with a low esr and high ah rating which takes a ton of strain off the alt. If you know mobile audio, you don't use capacitors, you would use a second battery with an isolator. 1200 watts shouldn't require a second battery if the rest of your electrical is up to par.

 

[Blue hedgehog]

I haven't built a car stereo system in 22 years, so I'm out of date on much of it. What I do know is electrical. When your 1200W amp is putting out its 1200W on a 12v power supply that's 100amps. I know the amp isn't putting out 1200W constantly but if its half of that its still 50amps. Unless you isolate
The amp and your extra battery from the cars existing wiring and come up with another way to charge your extra battery you will eventually have dimming lights.

 

[SolemnSinner]

Ok. Just ran another test.

Started Sonic.
Checked initial voltage @ the battery, and @ the amp with the dmm.
fluctuated between 14.5 and 14.9 volts.
Voltmeter on dash confirmed those readings(voltmeter confirmed to be calibrated accurately).
Turned on headlights. Turned on heater. Turned on dome lights.
Voltmeter held steady at 14.5 volts.
Dmm'ed @ the battery and at the amp. 14.5 volts.
Good #'s. Steady across the board.

Began playing "Lemonade" by Gucci Mane.

Initially, voltage dropped only from 14.5 to 14.1 on heavy bass drops.

As the music played and played and played on and even into the next song on the album, the voltage began to drop steadily down into the mid - high 13's.

Conclusion, charging system cannot keep up with the demands of the amplifiers power draw.

Remedy: Replace stock under hood battery with Kinetik HC1800 or comparable and beef up the grounding.

For reference, I had this same system installed in a 95 prelude, stock 90 amp alt, no big three, stock battery, and had ZERO dimming issues(dash, interior lights, headlights). Granted, the Prelude wasn't nearly as accessorized, and I think that's one of the reasons I've been having the issues here as I previously suspected.

 

[Blue hedgehog]

It doesn't matter if you put a 8D battery in your car. If your charging system can't power your loads you ask of it the battery will eventually die unless you take away the loads while charging.

Think of it like your savings account is your battery and your pay check is the alternator.

 

[SolemnSinner]

It doesn't matter if you put a 8D battery in your car. If your charging system can't power your loads you ask of it the battery will eventually die unless you take away the loads while charging.

Not all batteries are created equal. That's why there is a niche for mobile audio batteries. You have to have the right battery with a super low ESR and an ample ah rating. And ftr, I don't sit there and listen to 30hz test tones for hours while I'm driving around. Music is dynamic. While there may be prolonged periods of heavy bass during certain tracks, it's never constant. Reputable mobile audio batteries are built to charge quickly between power draws drastically reducing the demand on the alternator.

...and it's common knowledge than NO battery lasts forever regardless of it's intended use.

 

[Blue hedgehog]

My point was that if your average draw on the battery is more than the max output of the alternator no battery will last.

I wasn't saying that any battery will last forever. My point was the battery would die as in needing a charge not replacement.

If the battery can be charged as quick as you say, and the alternator isn't near it's limit with all of the OEM accessories you may be fine. I know the stock batteries are designed for starting purposes and minimal stand by power. The alternator is supposed to power everything plus charge the battery.

Do you have a amp clip for your DMM? If so, clip it on start the car and turn on all of your accessories like rear defrost, heated seats, headlights, a/c on high etc. and see what the car itself can draw from the alternator. I wouldn't be surprised if when everything is on your almost at the capacity of the alternator.

If you don't have an amp clip I do. If you want I can check on my car later when I get home.

 

[SolemnSinner]

My point was that if your average draw on the battery is more than the max output of the alternator no battery will last.

I wasn't saying that any battery will last forever. My point was the battery would die as in needing a charge not replacement.

Understood completely.

This is why on my old CRX where I was pushing 3200wrms, I had a H/O alternator(165amp, stock was 60amp lol) and two batteries(Shuriken BT80).

For my application here(1200wrms), the stock 100amp alt with a Kinetik HC1800 or comparable powercell under the hood should suffice for helping rid myself of dimming issue, which is slight, but noticeable. I think down the road I will probably upgrade the alt, but I'm not even sure they even make a H/O alt for this car yet. I suppose I could contact Mechman about that.

 

[SolemnSinner]

Do you have a amp clip for your DMM? If so, clip it on start the car and turn on all of your accessories like rear defrost, heated seats, headlights, a/c on high etc. and see what the car itself can draw from the alternator. I wouldn't be surprised if when everything is on your almost at the capacity of the alternator.

If you don't have an amp clip I do. If you want I can check on my car later when I get home.

Actually, no I don't have a clip. That would be really cool of you to check it out for me.

I do realize that there is a reason Chevy put that size alternator in the vehicle in the first place and it was not so I could have extra power to run my aftermarket equipment. lol

 

[Blue hedgehog]

Ok here's what I found.
At idle everything off 18 amps

Heated seats, heat on high, rear defroster on, headlights on low beam and fog lights on, radio on at low/moderate volume. 87amps.

All of the above plus front and rear wipers on high 95 amps.

My guess is the alternator is only capable of 95amps at idle and the battery was discharging with everything on. I don't have more time or I would continue testing.

I think it's time to start looking into a higher output alternator.