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    joenavy's Avatar
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    Amp Killed battery and alternator twice

    hello I have a 03 hyundai xg350l with a polk audio 400.1 and alpine mr300 installed in it. Since installing the two amps my battery has died and alternator has been replaced twice. When I connect the terminal to the battery sometimes it gives a lil arch is that normal? I replaced the alternator in march and battery last month the battery died again I took it to the audio shop they said the factory amp was bad I did a factory amp bypass then shortly the alternator dies on the car....I have disconnected the two amps now.

    What can I do to fix this?

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    Re: Amp Killed battery and alternator twice

    A few things, big 3, you should be able to find a how to somewhere on these forums probably under electrical, upgraded battery should help out alot, and lastly high output alt, from reputable company like mechman, dc etc...

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    Re: Amp Killed battery and alternator twice

    I think before we go doing our usual -- get a big battery, get a high output alternator, do the big 3 routine we need to actually consider what may be happening.

    You have 600-700w of amplifier power and a car that uses a 120A alt.
    There is really no reason to expect your electrical system troubles are due to too much long term current draw. Unless you're all-out blasting non-stop your sound system isn't much more of an impact on the electrical system than running your headlights and hvac blower at the same time.

    What is the mileage on your car? Alts don't last forever. If you have ~100k or so on your car there's no reason to be surprised your alt failed - with or without aftermarket electronics.

    If you had an alt failure while using an older battery it would not be surprising if the battery didn't recover.

    What type of replacement alt did you use? The off-brand (cheap) rebuilt/reman options are hit-or-miss in terms of durability.
    I always make sure to buy a replacement alt with a lifetime warranty since after the OEM dies my replacements have shown a tendency to only last a year or so.

    Have you double checked all the electrical mods you've made?
    It is possible you made an error causing a constant (probably small) drain on the battery, weakening it, making life harder on the alt trying to keep it charged --- one small problem leading to larger ones.

    FWIW - I've been running ~1500w with 110/130A alts, stock batteries, and minimal wiring mods. Alts do fail once a year or so, but I figure a couple hrs replacing the alt is the price I pay for running what I run.

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    Re: Amp Killed battery and alternator twice

    That setup should not in any way ruin an alternator or the battery. I suspect something else is going on.

    What is the voltage when your car is off and when it's on? When off you should see around 12.2~12.6v and at least 13.8v when the engine is running. Who installed it? How did they bypass the factory amp and why is it bad? Is it still in the vehicle? Maybe the factory amp has a shorted output and pulls a ton of current when it gets turned on.

    I had a Profile AP2000 amp that had no visible damage but a shorted output device and when it gets turned on it immediately starts to pull over 25 amps (the max my DMM can handle). That thing could have ruined the battery/alternator if left hooked up in the car... alternator unable to keep up with current demand, unable to keep the battery charged, the rest of the car is still using power... equals to dead alt and dead batt.

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    Re: Amp Killed battery and alternator twice

    first thing i would do, is look at the wiring. i've seent his a lot. both in auto, and tractors. if the cables are not up to par, it can just keep taking out alternators, and, in turn, batteries. the engine-body, and battery-body grounds usually are not in great shape on a factory vehicle after a while, and constant loads of an amp can slowly cook the alternator paower cable so that it acts like one big resistor. not to say that the replacement wasn't a dud, as mentioned already, or that the factory amp bypass was not done right, just saying, that it's usually the simpler things that get overlooked.

    *IF I have forgotten to exchange feedback, please let me know*
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    No, i will not "gift" paypal. please do not even make it awkward by asking. if the fees are an issue, I am usually inclined to add them. unless you have discount elsewhere, shipping is through usps flat rate, through usps parcel post, or through the roof..... i am in alaska. thanks
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    Re: Amp Killed battery and alternator twice

    All of the above is helpful, and you should follow that advice. On top of that, you need to disconnect all of your aftermarket audio to narrow down the problem in this situation. Dismiss those factors from the equation. You said it all started when you hooked that all up, but how do you know it is that equipment? Maybe there is a wire that you just disconnected and reconnected somewhere that is causing the problem. You should comb over your electrical system, without aftermarket equipment, from the beginning. Go over everything. Electrical problems will not just go away (for the most part), they tend to only get worse.

    To be honest I'm surprised you didn't do extensive testing after the first alternator and battery replacement.

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    Re: Amp Killed battery and alternator twice

    buy 14 88ah cnd batteries. stack them in the back seat. wire them up. take the amps out of the car. thake the batteries out of the car take the subs out of the car. put everything in your living room. add some more speakers a head units and ... what were we talking about?

    ^_^ any and all information you need is already here for you by previous posts.

    1. Test for draw with car off.
    2. test draw and voltage drop with car on and system on.
    3. test draw and voltage drop during car on with system at full tilt (or however loud you play it).
    4. test draw and voltage drop during car on with system at full tilt (or however loud you play it), lights on, air on, etc.
    5. Should be no whine from alt.
    6. Battery resting voltage should be 12.4-12.9 i say? and have it tested for CCA and CA reserves
    7. Stick 8 gauge in your peehole and 0 gauge up your bum and see if you feel electrified. (this wont accomplish anything but i truly suggest you give it a shot...)

    Possible fixes:

    1. Make sure you dont have a constant power going to the amp. I.E it staying on after you turn the car off.
    2. big 3 upgrade to reduce electrical resistance and widen the gap for current to flow.
    3. buy a HO alt.
    4. Buy a better replacement battery (xs power battery would be a great investment...)
    5. Sell those amps and sub(s)
    6. Buy my 18s and my american bass vfl 150.1s, bag the car, add at least 6 more batteries in the back. buy a ho alt. wall the car. become a know it all after being imersed by car audio for only 2 months.

    I say do #6 . Ish is the real deal baby good luck cutie.

    but yolo *****.

    New setup:
    1996 tahoe
    1/0 ofc american bass wire
    12x 15" bassaholic audio 15's (1500rms) (have 2 of 12)
    2x 350 amp singer
    2x 5k amps (cant say company lol, have 1 of 2 amps)
    6x batcap 4000s
    Pioneer 80prs or a kenwood hu
    2x 200x4 @ 4ohm amps (cant say company lol, have 1 of 2)
    buying piece by piece... Ready by sbn 2013 (i hope)

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