hi guys i have a question i just got my 180 amp alternator in from repair and i did a voltage check on my system with my lights on. and with the music up all the way playing a bass cd my voltage off the battery gose from 14v to 12v is that good or should it be like 13v.
the alternator regulates the voltage between 13.5 and 14.4 volts. if the engine is on then the alternator is generating the current. It has a voltage more than the ~12v battery because it has to overcome the batteries resistors to have a greater voltage potential and to charge the battery while the engine is on. because of the fact it is around 14v's means that alternator is doing its job, but it sounds like the alternator may not be able to keep up with the current your system is pulling and dropping the voltage.
i would guess that one of two things are happening. either the gains on your amp(s) are set too high and are pulling a lot more current than what they need to get rated power, or the alternator you have has a very low idle amps. a good way to test is turn the gains down a bit from where you have them set and see if the voltage with music still dips down towards 12v(the best solution would be to set your system up with a DMM to ensure the gains are not the troublemaker). also try have some one rev the car up to about 1500 to 2000 rpms while the music is playing at the gains you have set right now and see if the voltage climbs significantly. with 2000 rpms you should want around no less than 13.8v with music at moderate listening levels. if it does come back up into the 14's with the car at higher rpms then you may just need to get a smaller alt pulley to increase the idle amps of the car.
other things to consider is have you done the big 3 and with what gauge wire. your alt may be 180 amps but the charging system is only as strong as its weakest link and will not make 180 amps without upgraded factory wiring (the minimum for the big 3 at 180 amps would be HIGH strand 4 gauge copper wire, but ideally using 0 gauge). post a bit more about the system you are running maybe to get a better idea of what could be going on also.
ok right now im useing 4 gauge as my big 3 upgrade i was told with the system i got and how much power im running 4 gauge should be fine. i got about 7 coming from my alt to my battery and about 2 feet for my grounds i even add another 2 feet ground off my alt to the body just to make sure my alternator is grounded.the subs im running are 2 12inch kicker l5's running at 1 ohm off a cadence z7000 amp. my hu is a clarion dxz465mp and im running all stock speakers now for the gain on my amp its set to about 75% and for bass boost im not sure havent check on that yet.im starting to think it could be my red top battery because its about 3 years old is there anyway i can test the battery to see if its weak befor i buy a new one
the big 3 should be done with 0 gauge in general. 4 gauge can work if it high strand but most 4 gauge wire just isn't enough. however, i would say your problem with low voltage is because the gain for the amp is up farther than it should be (and that isn't even considering the bass boost). the preout voltage for that deck is only 1.8 volts but i would say 75% is probably too much. bass boost also pulls a lot of extra current and should in general not be used. the more current you pull the less voltage you have in a system that can't generate enough amperes for it. if your battery still reads around 12-12.5v's when the engine is off then that means the battery would not be the cause of the voltage issue. amps become inefficient when they are asked to make more wattage than they are rated for and by turning the gain up too high you are pulling more current that will end up getting wasted to inefficiency to get just a little bit more out of the amp. this is what causes amps to clip; they have to work a lot harder to try and produce more than rated power and send a clipped signal to the subwoofer. the clipping may not be audible but it will still be there.
well im getting a new deck in a few days the clarion dxz745mp it has a 4volt preouts u think with it being 4 volt u think it would help out on the voltage problem to. but yea im gonna work on it some more tomorrow i'll turn the gain down some and see if that helps some and i will make sure bass boost is off on the amp and deck
higher preout voltages just mean the gain is set differently to match with the head unit. the voltage pull for the same wattage is going to be the same with the gain knob turned up less. 4volt preouts though are good for eliminating the noise floor experiencing in a gain when the gain knob has to be turned up a lot to much with lower preout voltages. you can set your gains perfectly with a DMM by burning a 50 hz test sound to a cd and reading the voltage of your speaker outs. turn all EQ and boosting/sound processing things off (like loudness/MX/bass boost) but put the subwoofer level control all the way up. put the volume at 75% of its maximum volume on the knob and aim for about 31.6v's on the meter voltage=sqrt(ampsxresistence) so sqrt(1000x1) which is 31.6v.
that will set it so your amp will never clip. if it isn't enough bass it is usually safe to turn it up very slightly to compensate for low bass levels in songs.
now where can i find a 50hz test sound at so i can burn it on a cd lol but there one problem the deck i have now dont have subwoofer control thats why i got a new deck coming in right now im useing the bass opion on my deck to boost the bass on my subs and one question how do i check the voltage on my subs do i turn run the system and place the + part of the voltage meeter to the + part of the speaker wire
thats why i got a new deck coming in right now im useing the bass opion on my deck to boost the bass on my subs and one question how do i check the voltage on my subs do i turn run the system and place the + part of the voltage meeter to the + part of the speaker wire