LIghts dim

[Plater 10+ year member]

I would have to agree with starting at the battery connections. A good quality ground wire from the battery to the engine and chassis is only going to coast 10 bucks or so and a little time. You might even get away with cleaning the metal surface that the ground wire connects too. That is the cheapest way to go first. Try it, it won't cost much see if there is an improvement. If there isn't then a new alt. or rewound alt could fix your problem. Because if you draw more current then the alt. provides the battery drains and voltage drops due to a litte thing called source resistance. If money is a problem look for high current rating alt. that are after market replacements. They won't be labeled HIGH OUTPUT but if they are rated higher in terms of current they should help. You could go to a car wrecker and look for bigger alt that are out of bigger cars, trucks that might fit in with little modification. A cap will only help if the alt has enough time between bass hits to recharge the cap from the last bass hit. You could try making the charging wire from the alt heavier gage wire so that there is minimal losses between it and the battery. Take a look at all the heavy gage wire conection to make sure that they are good and clean. Clean them up and cover them with a good conductive grease. A bigger battery could help assuming that the alt. can keep up with the loading.

 

[vasyachkin 10+ year member]

goddyd4me - lights dim when on musical peaks the amp draws so much power that there develops a considerable voltage across the battery's "internal resistance" every battery has it, its even listed in battery's specs sometimes. you can have zero resistance wire but the batter will ALWAYS have it. putting a second battery in parallel will halve it, and halve the voltage drop across it.

no you will not be able to squeeze more long-term power if you keep playing at max volume for hours, but assuming that you only crank it up real high for a few minutes and mostly using battery at this point ( unless you're doing 120 mph on highway, and not parked ) then a second battery should nearly double your peak power.

 

[MikeofTulsa Moderator]

but unless your current alt. can handle the extra charging that it will have to do then i wouldnt recomend running 2 batteries...

 

[chris229 10+ year member]

Originally posted by vasyachkin goddyd4me - lights dim when on musical peaks the amp draws so much power that there develops a considerable voltage across the battery's "internal resistance" every battery has it, its even listed in battery's specs sometimes. you can have zero resistance wire but the batter will ALWAYS have it. putting a second battery in parallel will halve it, and halve the voltage drop across it.

 

no you will not be able to squeeze more long-term power if you keep playing at max volume for hours, but assuming that you only crank it up real high for a few minutes and mostly using battery at this point ( unless you're doing 120 mph on highway, and not parked ) then a second battery should nearly double your peak power.

I think your refering to a voltage drop across the battery due to its internal impedance. yes--- this can happen. putting another battery in parallel with the first does reduce it. Thing is the batteries aren't going to help with the load of the system UNTILL the voltage drops to the batteries level--- lights would already be dimming

 

[MikeofTulsa Moderator]

wow chris...for once we are agreeing on an issue...heh

 

[chris229 10+ year member]

well I didn't really agree----yes he is right about the batteries BUT adding a second doesn't fix a dimming light problem because the the drop that causes the lights to dim occurs above the voltage of the batteries-----so no matter how many batteries you have they can't help

 

[vasyachkin 10+ year member]

"the drop that causes the lights to dim occurs above the voltage of the batteries"

i am not sure what you're trying to say here, there are only 2 sources of voltage - battery and alternator. to say that voltage is about that of batteries would imply that the alternator is currently charging the batteries - but if alternator is able to charge the batteries even during a bass peak, then why do we even need a battery in the first place ? if even during peak demand the alternator is being able to both meet and exceed it and have extra to charge the battery -- certainly this is not happening. certainly during a bass peak a battery is beind discharged and the voltage is precisely that of the battery, (or less if power wire is not thick enough).

battery and power wire are in series and both will drop the voltage at high current demands, you have to minimise both, look up the specs on a typical battery's internal resistance, then look up tables that show resistance of wire based on length and gauge of it, and decide which is the bottleneck.

i dont think a second battery would somehow strain the alternator when it is being charged, after all it will never take more current than alternator will give it.

on the other hand if you abuse your new higher power of system, then you will run the batteries down because alternator will not be able to recharge them as fast as you will be able to discharge them.

 

[chris229 10+ year member]

Originally posted by vasyachkin "the drop that causes the lights to dim occurs above the voltage of the batteries"

i am not sure what you're trying to say here, there are only 2 sources of voltage - battery and alternator. to say that voltage is about that of batteries would imply that the alternator is currently charging the batteries -

yup--- it is always charging the batteries when the car is runing

but if alternator is able to charge the batteries even during a bass peak, then why do we even need a battery in the first place ?

I never stated that the alt is charging the batteries and has enough current to run the system too----if it does all the better----you know what a battery is for ---to start the car an to help with load exceeding the alt

if even during peak demand the alternator is being able to both meet and exceed it and have extra to charge the battery -- certainly this is not happening.

lights dimming doesn't really mean that the alt has given up----rather there is just a voltage drop

certainly during a bass peak a battery is beind discharged and the voltage is precisely that of the battery, (or less if power wire is not thick enough).

k---so in your case your saying the current has exceeded the alt ability and now the battery must help......well are you over looking the fact that the voltage has just dropped from 14.4 to 12.8~12.6 which is a 1.6~1.8v drop and this is before the batteries can even help--------that =dimming lights---now you see what i'm saying

i dont think a second battery would somehow strain the alternator when it is being charged, after all it will never take more current than alternator will give it.

yea it isn't going to take more current than the alt will give it ---------but it taking current-----taking more of the alts[current] head room.

on the other hand if you abuse your new higher power of system, then you will run the batteries down because alternator will not be able to recharge them as fast as you will be able to discharge them.

yup ----by adding batteries you can reach a point where you need a bigger alt cause you need to charge more batteries----catch22

 

[vasyachkin 10+ year member]

i guess the way to test your theory is to turn on the lights, and then shut off the engine, if the lights will dim by the same amount as during bass peaks, then you are correct. on the other hand if they will dim less than during bass peaks then we are both correct.

 

[chris229 10+ year member]

Originally posted by vasyachkin i guess the way to test your theory is to turn on the lights, and then shut off the engine, if the lights will dim by the same amount as during bass peaks, then you are correct. on the other hand if they will dim less than during bass peaks then we are both correct.

this isn't a test-----turning off the car puts the highest voltage at 12.8v [open circuit battery] all loads will cause even MORE voltage drop on the battery

 

[vasyachkin 10+ year member]

ok ok, a better test would be to just use a freaking voltmeter //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif i dont know if any voltmeters can react fast enough to register momentary voltage changes though as they occur on bass beats ...