Amp fried alternator or just a coincidence?

Macsrule15

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hey yall heres something ive NEVER seen before hopefully ya'll will have some input to help me weed about the problem before i drop another alternator in it and fry that one

friend gave me a amp the other day Crunch P1100.2 wired it up cleanly and the proper way.. wire the sub one voice coil per channel 275 RMS each channel to my alpine typeR woked great only played it for about 10 min then called it a night

go back outside in the morning car is dead as a door nail... doors wont even unlock by Fob throw a charger on it then start it up works fine untill my Brake,doors,and seatbelt i think? came on.. ive done some searching on here and i see that means alternator...

soo is it a coincidence that my alt fried the same night i installed a sub and bumped for 10 min? or did the amp cause it? the amp and wiring shows No signs of having anything wrong with it.. wiring is the exact same i have been using for months... and the same sub..

ive unhooked the amp but the alternator problem persists..

whipped out my multimeter and the resting voltage was 12.2.... idling voltage 13.9.... revving voltage 14.5... but then after a short rev the idling voltage dropped to 13.2
so the alternator is still working (sort of..)

i'm at a loss right now.. dont wanna throw a new alt at it and have the new one fry too... but that amp sounds REALLY clean! dont wanna dump it if i dont have to!

any input would be greatly appreciated!

thank you everyone!
 

blackcord

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It seems your resting voltage of 12.2 is low. Mine is usually at 12.6v (with no accessories or light on). So I am thinking, your battery is low on charge or defective. My idle voltage is usually 14.3 - 14.4v with no lights, fan or accessories on. It will drop when I got my lights or system on to 12.x - 13 (depending how loud I am playing my music), and revving will usually bring it back up to close to 14.x.

Since your alt is bring up the voltage when revving, then I am thinking that it is fine. You should take your battery in to a store that can do a load test on it.
 

chrismister2k1

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The easiest way to check if the alternator is bad is have the car running and disconnect the negative cable if the car turns off then the alternator is bad and usually when all the lights come on the dash it is because your alt is bad
 

Macsrule15

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The battery is 1 month and the most expensive interstate battery i could buy im sure its fine

Woke up this morning and the car is dead as hell again
No amp hooked up remember my resting voltage was taken right after i did a quick jump from a charger so it will be low

The alternator is bad i Know that now but my question is can a amp ive never used before cause this?
 

lashlee

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I've seen all kinds of problems associated with a stereo but my Accord is still rocking the original alternator with 210k miles on it. An alternator can die if the voltage of the battery is dropped and the alternator has to overwork to build voltage back in the battery. If the alternator was older and the voltage had dropped significantly in the battery while you were testing the new amp then it could be the culprit. Either way you've got to replace it, but personally the amp alone shouldn't be the problem.

As a side note I've got three amps, two batteries, as well as all the added goodies that goes along with a competition system so don't be quick to point blame to the amp.
 

LeBirdNest

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if your cars electricity is around 11-12v with the car on, its your alternator below that its your battery.
 

6thGenJed

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The battery is 1 month and the most expensive interstate battery i could buy im sure its fine

Woke up this morning and the car is dead as hell again
No amp hooked up remember my resting voltage was taken right after i did a quick jump from a charger so it will be low

The alternator is bad i Know that now but my question is can a amp ive never used before cause this?


just cause you bought it "new" a month ago doesnt actually mean its a month old. the actual day that it was sent out by manufacter is in numbers. like lets say the month as for January would be A/? and Feb would be B/?
im curious if you ran a fuse from the battery, then to your amp(and also if your amp it self had a fuse). if you did this im sure your alternator wouldnt be fried. and also if you have a power switch to control your amp to turn on or if it just turns on with the car cause alot of times it will stay on if you dont.
 

6thGenJed

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The battery is 1 month and the most expensive interstate battery i could buy im sure its fine

Woke up this morning and the car is dead as hell again
No amp hooked up remember my resting voltage was taken right after i did a quick jump from a charger so it will be low

The alternator is bad i Know that now but my question is can a amp ive never used before cause this?

if you think its the amp is causing it, sell it to me since its "broked" ;]
 

swollen_cu

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You sure your remote wire didn't fall out? That could be causing your battery to drain also.
 
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