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Hi, i just install a amp and sub in my trunk today. 12V power directly from car battery with inline fuse, ground wire I used a hole in the trunk, i sand the surface to remove the paint and tight it down with a screw. Audio from the headunit and the remote cable to the headunit 12V power. I notice that my subwoofer sound more powerful before the engine start, after the engine started the subwoofer sound weaker. After i stop the engine the subwoofer sound powerful again. It had a significance different between the engine started and stopped. Can anyone tell me is that normal all i do something wrong of the install??
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No, that isn’t normal. I would try doing a voltage drop test between the positive terminal on the battery and your amp, and between the ground terminal on the amp, and the negative battery cable.
Before I put the sub in the trunk so when the car started it sound weaker and i feel it with my hand is vibrating. but i think the weak bass i hear was from my rear speaker and the vibration also from the rear speaker. Today I check the sub and amp at night, i move the sub to the rear seat, and try to feel the sub with my hand when engine started but is not work. I saw i red light on the amp, is not a bright red light so I miss it on daytime. The fact is the amp is working when engine no running and stop working as soon as the engine started and it working work again after engine stopped. Hope you can understand what I’m trying to say. Before the engine start is 12.47v after the engine start 14.4v. I check the voltage from the amp power input, i also measure the voltage from the battery and the are same as above. I test all wire again, by remove the speaker wire, is green light before engine start and red light after engine started. I do the same things for relocate the ground wire, connect the remote wire to the amp power input and other 12v wire. It is same before engine start is green light, turn red after engine started. But i found a thing is when I’m not using power directly from the battery, I took remote wire from head unit connect to power input of the amp and run a wire from the amp input to the remote of the amp. You know what, is green light before and after engine started. It working if I’m not using power from the battery. Is it possible the battery have to high voltage for the amp, so put the amp in protection mode?? Or is it the power cable/ fuse have problem?? Is it ok/ save to take power from the head unit remote wire?? thanks
Not quite able to totally decipher all of that, but you may wish to verify the 12v turn-on line(remote on for amp) is actually powered when the vehicle is on. If you have an after-market head-unit, you’ll want to use the amp remote line specifically when provided for the amplifier’s turn-on circuit to avoid the turn on/off thumping..
You may wish to actually look at the manual, as it will list the conditions on which a red/green LED will be on. Usually if due to a fault, they will flash, not be a solid color, but your mileage may vary.
This in particular is confusing me, are you saying your daisy-chaining the remote lines between the two?:
I took remote wire from head unit connect to power input of the amp and run a wire from the amp input to the remote of the amp.
When “remote” is specified here, it’s naming itself as a remote turn-on, 12v, in this case, and should not have any real load placed on it. It’s only there(from the headunit) to tell the amp to come on or off. Again, the manual should go through all this as there’s usually just 3 power specific connections on most amps.
You should have a direct, proportionally gauged line from a direct battery connection for main power, same or better gauge for the ground to body, a remote line from the head-unit to turn on the amp, the audio inputs and outputs to speakers. That’s it.
I check the remote is 12v. I connect the remote wire from Head unit to the amp positive and run a wire from the amp positive to the amp remote. This is the only way I can make the amp and sub work. I know this should not be a good way or even a bad way to get power from. But i don’t know what is the problem with the power wire from the battery, it have inline fuse close to the battery.
[quote=”jack437hk” post=105800]I check the remote is 12v. I connect the remote wire from Head unit to the amp positive and run a wire from the amp positive to the amp remote.[/quote]
Uhm, again, what?
Can you list what amp brand and model you’re using?
There should be:
1 – 12volt constant, this is the main power draw for the amp when turned on, it needs to be constant on, not necessarily a direct battery connection, but on a main line that can handle the extra draw(both the line’s gauge and whatever fuse it uses).
1 – 12volt P.CON/IGN/etc, this should be hooked up to the remote line from the head-unit. This tells it to turn on.
1 – Ground, main ground for the amp.The above is it. If that amp has another “remote” line, it’s just for turning on other peripherals, in other words you have no need of it.
11v-16v is the normal operating voltage of most units, so 14.4v is fine. It still sounds like something is hooked up wrong, causing it to shut off when you have the vehicle running.
That definitely does NOT sound like it is wired up right.
You SHOULD have:
GROUND . . this needs to be a heavy gauge wire, perhaps 8, or even 4 gauge depending on the power of your amp. It connects the negative (-) terminal of your amplifier to to body ground. This will preferably be connected to a bolt that goes into the chasis / frame of the car, not just a screw in the sheet metal, and you will have cleaned the paint away before bolting it down. It IS ok to paint OVER the wire to protect the exposed metal from rusting. Make certain this connection is clean, and tight.
POWER . . this wire should also be 8, or even 4 gauge. It connects the positive (+) terminal on your amplifier directly to the positive terminal on your battery, and should have an inline fuse as close to the battery as possible. The fuse in this wire needs to be have at least the same capacity as the fuse in your amp. If your amp has a 30 amp fuse in it, then the fuse in your power wire must be at least 30 amps. If it is any smaller, it will not be able to handle the power draw from the amplifier. Check to be certain that the fuse has continuity, and that you are getting a full 12v (14.4 with engine running) at the positive terminal on your amplifier.
REM . . . this terminal is for the wire that tells the amplifier to turn on when the head unit is powered on. This wire can be much smaller gauge, perhaps 18 or so, and should connect to the REM / ANT lead from your head unit (often a blue wire on after market units). This wire should show 12v positive when your stereo is powered on. If you are NOT getting 12v positive here with the stereo on, then your amplifier will not power on. Make certain you have the correct wire from your stereo, and if it is no longer putting out 12v with the stereo on, you could connect the REM terminal on your amp to any circuit that has 12v positive ONLY when the car is on. Sometimes the lighter outlet works for this.
Those are the ONLY connections you should have to your amp. Running a wire directly from the + terminal on your amp to the REM terminal would keep your amplifier turned on all the time, which will shorten the amp’s life, and drain your battery. Trying to use the REM lead from the head unit to power the amp will draw too much current from the head unit and kill it.
Double check your connections. Make certain that your big power wire has 12v at the amp. Make certain that there isn’t a lot of resistance through your ground wire, and make certain that your rem wire has 12v positive when the stereo is turned on. If all of that is right, your amp should come on with your stereo.
[quote=”Ratchet Face” post=105796]you should try adding a capacitor to your sound system and see if that helps.
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“Caps” are a band-aid solution in 90%+ of applications.
Actually, caps do absolutely nothing in 99% of installations.
The link here is a nice write up on exactly why cap’s don’t really work.
+1 to above, afraid they’re garbage.
If there are dimming, or power issues, best thing is to first double-check all your connections (corrosion free, clean and tight). That doesn’t do it, next is to upgrade wiring; grounds, main power, usually whats referred to as the “big 3”.
http://www.the12volt.com/installbay/forum_posts.asp?TID=73496
After that, you’d need to think about getting a high-output alternator/generator for your vehicle, and possibly a second battery on an isolator. These last few steps are usually only necessary if you’ve put in more than 1 amplifier, or are drawing more than 700-800watts RMS overall from them/it in most cases.Agree completely with the above.
Clean tight connections, and the BIG3 (and a lot of times, just doing the grounds is more than enough to get you through). I am running about 600 watts total with two amps, and I have no problems running a single battery, and stock alternator. My alternator is new though, and I have upgraded the ground cabling in my car, as well as replacing the power cable, which is only stock, but it is brand new, so there is no corrosion. I have absolutely zero issues with my battery discharging, and only get a slight bit of flickering when I’m really pushing the stereo, and have headlights, wipers, heat, and defroster all running at the same time. Generally, I get zero flicker.
Wire everything properly, and make sure that the alternator is in good working order, and that it’s drive belt is in good condition, and properly tensioned, and you should have no problems running 500 – 800 watts.
The link I posted about caps is an awesome read, and is explained quite well. I’ve followed along, and done the math, and it is 100% right. My background is in electrical engineering, so I do have at least some idea of what I am talking about lol. I understand it, but that article does a great job of explaining it. In the end, what it comes down to is by the time the system needs the cap, and the cap tries to deliver, the voltage it has available for the system has already dropped down below the voltage that the battery can supply, and so the battery takes over, and the cap, literally, does nothing but draw power FROM the system to recharge it’s self.
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