flat battery due to extra demand from amps/subs

[Sabby]

why is it bad to take off the negative first?

 

[cxcxcxvcvcvc]

why is it bad to take off the negative first?

well get this,
in the max ellery when ever you carry out any electrical work on your car you are supposed to take off the negative battery cable first before the positive (this is to prevent a possible spike to the cars computer or so it reads) but..
when you install your amps it will tell you that the last cable to go on should be the positive right? (to avoid blowing your amp) so if you take the cars negative off first when carring out any work your effectivly allowing only a direct positive feed to your amp,head decks ect which is what the manul says not to? as it says to put the earth cable on first. The only way around this is to disconnect your positive power cable to your amp first. then remove the negative cable and then the positive unfortunetly when you take your car in to get fixed, serviced or work done most people arent thinking of your amps in the boot and just take of the neg cable first:bang:

 

[cxcxcxvcvcvc]

so would it be possible for the amp to blow due to someone doing welding on my car?

 

[myvtspack]

hey hows it goin mate wat sort of commy is it. i have a vt running a fusion powerplant 1500watt running two pioneer 15s and a fusion 400watt running my 6x9s and i killed my alternator. i put a 100 amp alternator $300 from repco and just put a standerd brand new battery and it runs beautifull plus running everything in the car the only problem i have is my battery light is till on but i have been told its not due to the system

 

[Garth]

so would it be possible for the amp to blow due to someone doing welding on my car?

no

it is pysicaly impossible for that to happen. goes against all laws of physics. i can tell you teh following

when you get a batter, it has a cca ratting, cold cranking amps ratting, this is how much the battery can produce for a period of time to start the car when cold. (usualy a tiem frame of 5 to 10 minutes.)

when you drive your car under normal conditions. i.e. say going down to the shops and back you car for example will use 40 to 50 amps from the battery to keep all systems running in your car, all sensors, brakeing bits, fuel pump, guages, all the stuff you can think off.

you remove yoru normal little radio and replace that with a monster and put a 1200 watt amp and sub in the boot. now, this is where it gets nasty. you are now drawing 70 to 80 amps from the batter, however due to restrictions placed on your alternator (electrical principles 3 and 4) your battery is now no-longer able to suply the demand needed by your car.

to sum it up.
stock alternator. 60-70 amps.
new radio and all other bits still there 80-90 amps
difference in current 10-20 amps
effect, battery goes flat and headlights will dip as alternator reaches saturation point (there point where it is un-able to produce anymore current)

sollution is replace alternator. and put a bigger battery in there also
or run a 2nd alternator in parralell with your current one, producing same voltage, 2wice the current. (will need a bigger battery)
while your at it, you will need a bigger earth wire

 

[cxcxcxvcvcvc]

no

it is pysicaly impossible for that to happen. goes against all laws of physics. i can tell you teh following

when you get a batter, it has a cca ratting, cold cranking amps ratting, this is how much the battery can produce for a period of time to start the car when cold. (usualy a tiem frame of 5 to 10 minutes.)

when you drive your car under normal conditions. i.e. say going down to the shops and back you car for example will use 40 to 50 amps from the battery to keep all systems running in your car, all sensors, brakeing bits, fuel pump, guages, all the stuff you can think off.

you remove yoru normal little radio and replace that with a monster and put a 1200 watt amp and sub in the boot. now, this is where it gets nasty. you are now drawing 70 to 80 amps from the batter, however due to restrictions placed on your alternator (electrical principles 3 and 4) your battery is now no-longer able to suply the demand needed by your car.

to sum it up.
stock alternator. 60-70 amps.
new radio and all other bits still there 80-90 amps
difference in current 10-20 amps
effect, battery goes flat and headlights will dip as alternator reaches saturation point (there point where it is un-able to produce anymore current)

sollution is replace alternator. and put a bigger battery in there also
or run a 2nd alternator in parralell with your current one, producing same voltage, 2wice the current. (will need a bigger battery)
while your at it, you will need a bigger earth wire

thanks for the info mate:thumbsup: if i replace the battery & alternator with a higher voltage item say 16 volts will the cars normal electrics be able to take it meaning i wont blow dash lights or computer & other stuff that requires only a 12volt input will i? i dont want computer wire looms to melt or nothin might sound dumb to ask but better safe than sorry im guessing it would be fine as my current alternator pumps up to 14 volts when running and thats standard.

 

[cxcxcxvcvcvc]

hey hows it goin mate wat sort of commy is it. i have a vt running a fusion powerplant 1500watt running two pioneer 15s and a fusion 400watt running my 6x9s and i killed my alternator. i put a 100 amp alternator $300 from repco and just put a standerd brand new battery and it runs beautifull plus running everything in the car the only problem i have is my battery light is till on but i have been told its not due to the system

it is a 96 vs v6 calais and that sounds like a nice setup you have there yeah i think im going to have to get my car alternator replaced as im not haveing much fun with the stock one lol. im saveing up from work to get some new wires and cableing and then im going to deck the car out properly with custom boot install for the subs, new head deck some jl splits up front some mid splits for the back and custom lighting. ive also been wondering what boston splits sound like they look pretty good but ive never heard them before. for the custom boot install i have been thinking of various designs and how i want it to look i spose thats where it comes in handy to be an apprentice carpenter i am pretty handy with custom lighting and fiddly stuff so when i get it all up i will put up some pics

 

[Tasmaniak]

i have dual 0g runs - hit 140.9 on TL without upgrading battery to chassis. Added 0g batt- to chassis earth - and hit 141?

Thats a 6% gain.

 

[garfa]

no i havent changed the earth cable it didnt realy come to mind? garfa yes my amp is only cea rated to 1600 wrms @ 14.5 volts but on the average 12 volts its arond 600-900 but i actually thought of something today while at work, a few weeks ago i had a set of pacey extractors installed by a well known muffler and exhuast place and they usually take the battery cables off to do the welding and im wondering if the have stuffed my amp by either 1 takeing the earth off the battery first (wich is not good for any car audio) or 2 wether the current from the welder has killed my amp? and you just know if thats the case i have no chance of getting them to fix it let alone prove it:bang: could this be the case?

well ****!
replace it! what good is it to have a bit postive cable but there to be a HUGE bottle neck on the negative side?!?!?!?!?!?!

 

[cxcxcxvcvcvc]

got the day off work so i am going to check/sort all wireing today and install new fuses in amp and give it a test run if it all works then i will take the amp back out & sometime next week maybe (if i can afford it) i will be able to put new earth cable on and maybe replace the battery or alternator.