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Discussion Starter · #1 ·
I have an 04 LX sedan MT, 100,000 miles. My alternator recently failed, I understand this will happen, however I'd like to make sure it's not due to my sound system and if so, what can I do about it? I have an aftermarket deck (JVC KD-A925BT) 2 Polk audio door speakers a Pioneer GM-5000t 760w amp (manual says current consumption 25a at continuous power) powering 2 10" kenwood KFC-W2509 subs 4ohms each wired one per channel. I know it's not much but the alternator is only 105 oem I believe. Battery and new alt are Honda oem installed by them. Only owned 1 1/2 years
 

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The Digital Bullet
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I've burned up countless alternators due to a large draw on my SPL shootout vehicles. I'd throw a voltmeter on it to see if it's being overworked. It's very plausible.
 

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03-SSM-AV6-6MT
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Damn, how much did Honda charge you for that?
 

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I have an 04 LX sedan MT, 100,000 miles. My alternator recently failed, I understand this will happen, however I'd like to make sure it's not due to my sound system and if so, what can I do about it? I have an aftermarket deck (JVC KD-A925BT) 2 Polk audio door speakers a Pioneer GM-5000t 760w amp (manual says current consumption 25a at continuous power) powering 2 10" kenwood KFC-W2509 subs 4ohms each wired one per channel. I know it's not much but the alternator is only 105 oem I believe. Battery and new alt are Honda oem installed by them. Only owned 1 1/2 years
The LX's charging system is barely adequate for normal operation. Heck, my lights dim slightly if I hold my window switches in the up position. Suggest you do the V6 battery upgrade and install a large capacitor. The capacitor won't increase your overall voltage but it will smooth out the peaks and valleys, which makes things a bit easier on the alternator and battery. Easier on your amp too.
 

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OK, remember why the alternator is there in the first place. It is there to supply electrical energy to the vehicle while it is running. So in addition to the load the normal electronics and fans put on the alternator you added an additional 25a of current needed. The energy comes from the alternator which converts the mechanical energy from the engine. The battery is just a reservoir for energy to start the car and to provide current flow when the alternator is not able to supply the whole load.

So, adding additional load will make the alternator work more, the components will wear out quicker, especially the brushes. So, you can add a larger battery, but that does not change the equation. Now 25a is not a lot of extra load as the alternator is capable of 105a of output. That output is variable due to the engine RPM's changing and idling lowers output. The 105a output is the highest the alternator can produce and it only produces enough to satisfy the load. So if the load is 80a the alternator is only producing 80a, not 105a.

Bottom line, if your current draw is not exceeding the output of the alternator you should be fine. Yes your Alternator will wear out before the same alternator in a car without an amp, but the power has to come from somewhere. Getting a high amp alternator is a waste unless you are drawing more amps than the alternator is capable of producing. You would be seeing a dead battery that would not start the car if the alternator could not keep up.
 

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Your puzzle is easily solved using PIE.

The 12 Volt has a nice chart to help you figure out the appropriate charging system for your application.

As others mentioned, your stereo system is not drawing full amperage all the time, and neither are the car's stock electronics.

I would watch for voltage drops. Since the Accord doesn't come with a volt gauge in the instrument cluster, you'll need to do this yourself at the battery posts with a DMM. If you're only seeing dips when playing music full blast, you'll need to decide on modifying your listening habits or your charging system.

And not to knock on your gear, but in my prior experience with Pioneer amps and unless things changed since 2004, their numbers are often over-stated. Something from the likes of MMATS (remember them?), JL Audio, JBL (when they made PowerValve not sure about the crap nowadays) and maybe Kicker (again older stuff not sure about now) will put out their rated power and tax your charging system accordingly, much to your alternator's detriment.
 

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Discussion Starter · #8 ·
OK, remember why the alternator is there in the first place. It is there to supply electrical energy to the vehicle while it is running. So in addition to the load the normal electronics and fans put on the alternator you added an additional 25a of current needed. The energy comes from the alternator which converts the mechanical energy from the engine. The battery is just a reservoir for energy to start the car and to provide current flow when the alternator is not able to supply the whole load.

So, adding additional load will make the alternator work more, the components will wear out quicker, especially the brushes. So, you can add a larger battery, but that does not change the equation. Now 25a is not a lot of extra load as the alternator is capable of 105a of output. That output is variable due to the engine RPM's changing and idling lowers output. The 105a output is the highest the alternator can produce and it only produces enough to satisfy the load. So if the load is 80a the alternator is only producing 80a, not 105a.

Bottom line, if your current draw is not exceeding the output of the alternator you should be fine. Yes your Alternator will wear out before the same alternator in a car without an amp, but the power has to come from somewhere. Getting a high amp alternator is a waste unless you are drawing more amps than the alternator is capable of producing. You would be seeing a dead battery that would not start the car if the alternator could not keep up.
Do you think a cap would help or hurt the charging system?
 

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Discussion Starter · #9 ·
Your puzzle is easily solved using PIE.

The 12 Volt has a nice chart to help you figure out the appropriate charging system for your application.

As others mentioned, your stereo system is not drawing full amperage all the time, and neither are the car's stock electronics.

I would watch for voltage drops. Since the Accord doesn't come with a volt gauge in the instrument cluster, you'll need to do this yourself at the battery posts with a DMM. If you're only seeing dips when playing music full blast, you'll need to decide on modifying your listening habits or your charging system.

And not to knock on your gear, but in my prior experience with Pioneer amps and unless things changed since 2004, their numbers are often over-stated. Something from the likes of MMATS (remember them?), JL Audio, JBL (when they made PowerValve not sure about the crap nowadays) and maybe Kicker (again older stuff not sure about now) will put out their rated power and tax your charging system accordingly, much to your alternator's detriment.
It's ok to knock my gear it's just stuff I've gathered over the years, so your saying it prob doesn't draw as much as it states? Which in my case would be a good thing. I don't understand that chart or just don't have time to figure it out lol. I also don't have money to upgrade the charging system (this is why my concern in the first place). I would have the knowledge and money to add a capacitor, however if that's not going to help my situation, id rather just take the beats out and upgrade my 6x9s in my rear deck (since 2004 honda stock is junk)
 

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At full tilt with the way your subs are wired, Pioneer claims 125W each. I've run that before using stock alternator and the lights hardly flickered at full tilt. The rest of the gear you mentioned shouldn't pull significant draw.

At 100k miles and assuming your alternator was original, I think you simply helped an aging, near EOL component get to the end faster.
 

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OK, remember why the alternator is there in the first place. It is there to supply electrical energy to the vehicle while it is running
AND.... to charge the battery.
So, you can add a larger battery, but that does not change the equation
A larger battery has deeper reserves and won't tax the alternator with "charge me" as much, while it's trying to provide the power to keep the vehicle running. Overall, it doesn't change the equation but adds sustainability with regards to current flow. Adding a cap furthers that.
Do you think a cap would help or hurt the charging system?
A capacitor charges and discharges much faster than a battery does, because it has a much lower resistance to current flow. Every time the voltage sags, the cap discharges and that lessens the large dip that the alternator has to make up for. That smooths out the current flow across the system. Imagine the alternator as a water pump. Each time the water pressure dips, the pump struggles to bring it back up. A cap would be a pressure tank that builds pressure and discharges water the instant pressure drops. Now, if the water flows at steady rate, the pump would work less - at a more even keel. It would overheat less and the brushes would wear less.

I'm not sitting here telling you it gives you more power.... your initial question was how to make your alternator last longer. The answer is stop putting it through excessive excursions.
 

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just get an autozone alternator.. lifetime warranty
 

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Carpe Diem
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The same week I drove my car off the lot I installed a nice sound system with a big old 5 channel amp to power four aftermarket speakers and a 12" sub. I installed a capacitor at the same time, even though most people I talked to told me it was a waste of money. Well 9 years later I'm still on my stock alternator. I'm not saying having a cap is the only reason my alt hasn't died yet, but I'm sure it has helped. The cap plus a good old Optima Yellowtop deep cycle AGM battery let me crank my amp as high as I need to without worry.
 
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