# I Step On The Gas, And My Subs Cut Out.



## Peteman720 (Jan 8, 2013)

Quite simply, when I rev the engine up from idle, my alpine MRX-M240 cuts out. Blue power indicator stays lit, but all output ceases for several seconds. The issue only occurs when at a moderately high volume, and may occur even when holding the engine steady at any rpm above idle. It is most common, however, when the engine goes from idling to 2k+ rpms.

The issue started right after I replaced my alternator. My other boston amps don't seem to flinch, so I doubt that the alternator is seriously defective--just different than my previous model. I believe that the issue revolves around the amp getting to high of a voltage due to the alternator not reacting to a change in load or rpm quickly enough. My question then is how do I deal with it?


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## Schizm (Jun 12, 2011)

Well you should definitely check the voltage coming off your alternator at idle AND during acceleration. Check voltage at your amp input for both as well. 

And since your there check the resistance of the amps ground line. 

Sent from my HTC6435LVW using Xparent Green Tapatalk 2


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## NJaNeer (Jun 8, 2013)

I am probably not the most qualified here to answer, but I would take a reading going to the amp in question. Also, check the ground power for any short circuits, yadda yadda. Oh and the fuze at the battery of course.

If you are getting a heavy spike it seems like this could be bad for the battery? Again. No expert.


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## Peteman720 (Jan 8, 2013)

Alright, some more information since I was a bit pressed for time during my last post:

My system consists of three amps (two boston GT's and the Alpine MRX-M240). I have it all wired with 2/0 copper cable and the Big Three has been done. My grounding point is the rear seatbelt bolt (sanded of course). I just recently upgraded to a 170Amp alt (1996 Accord by the way), but my battery remains stock. I added a one farad capacitor in hopes of flattening out the spikes but to no avail.

I have been attempting to measure the voltage my amp is getting, but it is tricky to tell exactly what is going on. None of my voltmeters are quite fast enough to give an accurate picture. Nevertheless, from what I can tell, there is a surge of power near the time at which the amp shuts off. At these times the voltage exceeds 15v, but only for a split second.

I am convinced that the cutting out is caused by excess voltage and not a lack thereof mainly because the amp will never cut out at idle--even if the voltage approaches 11v.

What I am really looking to find out is whether there is any method by which I can filter out these spikes or disable the internal protection on the amp. I would return the alternator, but I bought it from a less than friendly company online and they don't accept returns once the unit has been installed. 

Also, would wiring the capacitor in series change is effectiveness as a filter? I'll have to google that...


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## [email protected] (Nov 7, 2010)

Can you measure right at the alternator? I am curious how high over 15v it is outputting. Does your meter have a peak-hold function?


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## NJaNeer (Jun 8, 2013)

[email protected] said:


> Can you measure right at the alternator? I am curious how high over 15v it is outputting. Does your meter have a peak-hold function?


Me too!
Did you check the output voltage from the rca's? 

Spec sheet of your amp:


Features and Specification
SPECIFICATIONS

CEA-2006 Power Ratings
CEA-2006 Power Rating: 1500W RMS x 1 (4-ohm, 14.4V at Ƈ% THD+N)
Max Power Output Ratings
Max Power: 2400W
RMS Power Ratings
Per channel into 4 Ohms: 1500W RMS x 1 (14.4V at Ƈ% THD+N)
Per channel into 2 Ohms: 2400W RMS x 1 (14.4V at Ƈ% THD+N)
Per channel into 1 Ohm: 1000W RMS x 1 (14.4V at Ƈ% THD+N)
Sound Tuning
Crossover Frequency (Subwoofer, LPF): 50-400Hz, -24dB/oct.
Crossover Frequency (LPF): 50 - 400 Hz, -24dB/oct.
Subsonic Filter: 5 - 30 Hz, -24dB/oct.
EQ (Equalizer): 0 to +12dB, fc=50Hz
Dimensions
Foot Print (WxHxD) mm: 462 x 58 x 230 mm
Foot Print (WxHxD) in: 18'' x 2-1/4'' x 9''
General
Power Requirements: 14.4 V.DC (11-16V allowable)
Input Sensitivity (RCA Input): 0.1 - 4.0 V
Input Sensitivity (Speaker Level Input): 0.5 - 10 V
Input Impedance: >10k ohms
Frequency Response (+0, -3dB: 1W into 4 Ohms) for Subwoofer: 5 - 400 Hz
Damping Factor for Subwoofer: >1000
Signal to Noise (Rated Power into 4 Ohms) for Subwoofer: 108 dB
Preamp Output: 4.0 V Max.
Remote Level: -20 to 0 dB
Weight: 5.4 kg (11.8lbs.)
FEATURES

Install
Terminal Layout: Two-Sided
Screw Mount / Wire Cover: Integrated Wire and Mounting Screw Terminals
General
Amplifier Type: Class-D (Digital)
Channel Design: 1 Channel (Mono)
Power Supply Design: DC-DC PWM Power Supply
Power Supply: MOSFET
Final Outputs: Direct FET
Crossover: Variable Low Pass Filter
Gain Control: Continuously Adjustable Gain Control
Subsonic Filter: Variable Subsonic Filter
Bass EQ: Bass EQ Function
Bass Control: Remote Bass Control (RUX-KNOB) Ready
Low-impedance Possibility: Low-impedance Possibility
Current Protection: Over-Current, Over-Voltage and Thermal Protection
Board Circuitry: S.T.A.R. Circuit
Board Design: 6-layer Glass Epoxy PC Board
RCA Output: Non-Fading Pre-Amp Output
Speaker-Level Inputs: 4-channel Speaker Level Inputs
Power Indicator: Top Mounted Blue LED Power Indicator
Thermal Control: Multi-stage Power Limiting


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## NJaNeer (Jun 8, 2013)

I would be concerned for the 4v max preamp output. So checking rca's at those power spikes may help.


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## Schizm (Jun 12, 2011)

[email protected] said:


> Can you measure right at the alternator? I am curious how high over 15v it is outputting. Does your meter have a peak-hold function?


This. I suspected your alternator was putting out too high of voltage at higher rpm. If your amp doesn't like these high voltages most will shut down to protect itself. 

Sent from my HTC6435LVW using Xparent Green Tapatalk 2


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## Peteman720 (Jan 8, 2013)

How would I go about checking the rca's? I would want to be measuring AC voltage between the center pin and the shield right? And when they aren't plugged into the amp won't their output be slightly different? I already tried messing with turning the gain up and the output from the deck down, but it doesn't seem to have done much.

I think my meter has a peak hold function, I'll try to get some more measurements.

Either way, I'm pretty convinced that whenever the alternator's rpm suddenly increases while it is under load, or its load suddenly drops off (after a big bass hit), the voltage skyrockets until the regulator can catch up.


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## NJaNeer (Jun 8, 2013)

Peteman720 said:


> How would I go about checking the rca's? I would want to be measuring AC voltage between the center pin and the shield right? And when they aren't plugged into the amp won't their output be slightly different? I already tried messing with turning the gain up and the output from the deck down, but it doesn't seem to have done much.
> 
> I think my meter has a peak hold function, I'll try to get some more measurements.
> 
> Either way, I'm pretty convinced that whenever the alternator's rpm suddenly increases while it is under load, or its load suddenly drops off (after a big bass hit), the voltage skyrockets until the regulator can catch up.


I think you pretty much answered your question. "voltage regulator" may be bad or allowing over 14.2V to the battery. Like the other guys said, start with the alternator. If your "stock" battery is seeing over 14.2V you could be overcharging the battery which could damage the electrical system and the battery. If the voltage regulator is faulty, all of the things you have mentioned would be a good sign for it.


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## Peteman720 (Jan 8, 2013)

Looks like this guy had the same problem: High Output Alternator Voltage Spikes - F150online Forums


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## Peteman720 (Jan 8, 2013)

NJaNeer said:


> I think you pretty much answered your question. "voltage regulator" may be bad or allowing over 14.2V to the battery. Like the other guys said, start with the alternator. If your "stock" battery is seeing over 14.2V you could be overcharging the battery which could damage the electrical system and the battery. If the voltage regulator is faulty, all of the things you have mentioned would be a good sign for it.


So I should try to get the alternator replaced? The spikes are only for a split second so I don't believe there will be any negative effects on the battery. I really don't want to send the alternator in because I doubt that the company will be very helpful...


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## NJaNeer (Jun 8, 2013)

Peteman720 said:


> So I should try to get the alternator replaced? The spikes are only for a split second so I don't believe there will be any negative effects on the battery. I really don't want to send the alternator in because I doubt that the company will be very helpful...


From what Peteman posted, the last comment made in that forum said the stock battery could be the culprit or the wiring could be. You can always have the battery and alt tested like that guy did at a auto parts store for free. If they turn out to be working, I would invest in a Diehard Plat battery.


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## NJaNeer (Jun 8, 2013)

By the way Costco has some Kirklands batteries rated at 1000 cca's
for under $100


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## Peteman720 (Jan 8, 2013)

I went to napa to have everything tested and their equipment apparently couldn't test my battery while the car was off due to "system leakage" which I attribute to my capacitor. He did say, however, that the alternator tested fine, but I don't think he even put a load on it or anything. 

If my battery is bad, would that make a difference? I assume that maybe a bigger battery would do a better job of absorbing the voltage fluctuations?

Also, I used the peak value setting on my DMM and got a max of about 15.5 Volts at the amp.


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## NJaNeer (Jun 8, 2013)

Peteman720 said:


> I went to napa to have everything tested and their equipment apparently couldn't test my battery while the car was off due to "system leakage" which I attribute to my capacitor. He did say, however, that the alternator tested fine, but I don't think he even put a load on it or anything.
> 
> If my battery is bad, would that make a difference? I assume that maybe a bigger battery would do a better job of absorbing the voltage fluctuations?
> 
> Also, I used the peak value setting on my DMM and got a max of about 15.5 Volts at the amp.


I know this is not the best place to get information, but a lot of these guys run ho alternators. 
alternator cold charging at 16v... problem? - Electrical-battery- Alternators- Wiring - SMD Forum
Sounds like the problem you are having. Another thread had a guy try a better battery but still had the problem. You may need to contact the people you got the alternator from and tell them you are getting 16v+ spikes. They should know how to remedy the problem better than I could. If you think that your amp going into protect is bad, imagine what it's doing to your electrical components.


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## NJaNeer (Jun 8, 2013)

Some more information to read up on.

How to stop High Voltage Surge? - S-10 Forum


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## Peteman720 (Jan 8, 2013)

It seems like the issue in the links above is a bit more prolonged than mine. My spikes only last for a fraction of a second--almost too quick to catch on my voltmeter. For this reason I'm not sure that its a defective regulator...

I went out a tested my battery: 12.25 volts with the car off and having not driven it for an hour or so. I set the meter on the minimum function, started the car, and got about 10.5 volts. Ive heard that the battery should be no lower than 12.4 volts. Could this be my problem? I also have alternator whine that I don't seem to be able to get rid of no matter where I ground things or how I filter the hu's power.


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## NJaNeer (Jun 8, 2013)

Peteman720 said:


> It seems like the issue in the links above is a bit more prolonged than mine. My spikes only last for a fraction of a second--almost too quick to catch on my voltmeter. For this reason I'm not sure that its a defective regulator...
> 
> I went out a tested my battery: 12.25 volts with the car off and having not driven it for an hour or so. I set the meter on the minimum function, started the car, and got about 10.5 volts. Ive heard that the battery should be no lower than 12.4 volts. Could this be my problem? I also have alternator whine that I don't seem to be able to get rid of no matter where I ground things or how I filter the hu's power.


Hrmm, let the car run for a little and test again. 10.5 volts is not good at all. Hard to say what's going on now that you say you have alternator whine. You deffinately have a ground loop somewhere. Make sure your big 3 wires are all tight and connected securely, check your power and ground going to the amps. Do you have a distribution block with a fuze? Check that. Check the fuze from battery to alternator, amp power wire fuze at battery. I know this all sounds stupid, but check wires for kinks cuts anything that could cause your alternator whine. While you're at it, take that capacitor out. How do you have those three amps grounded? Distribution block or 3 wires going to the seatbelt bolt?


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## NJaNeer (Jun 8, 2013)

Here is a troubleshooting guide for alternator whine:

How To - Car Stereo - In Pursuit of a Noise-Free System: The Ten Commandments of Noise Prevention

If you scroll down you will see a section for alternatir whine.


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## eisnerracing (Sep 14, 2010)

Like everyone said sounds like the voltage regulator is bad 
Putting out to much power above 2k
I see this in old hot rods a lot bad external voltage regulator 
But if this is a new car it's inside the alt.


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## Peteman720 (Jan 8, 2013)

NJaNeer said:


> Hrmm, let the car run for a little and test again. 10.5 volts is not good at all. Hard to say what's going on now that you say you have alternator whine. You deffinately have a ground loop somewhere. Make sure your big 3 wires are all tight and connected securely, check your power and ground going to the amps. Do you have a distribution block with a fuze? Check that. Check the fuze from battery to alternator, amp power wire fuze at battery. I know this all sounds stupid, but check wires for kinks cuts anything that could cause your alternator whine. While you're at it, take that capacitor out. How do you have those three amps grounded? Distribution block or 3 wires going to the seatbelt bolt?


The 10.5 volts is the minimum voltage which was reached while starting the car. From what I've read online, anything above 9.6 volts is acceptable under these heavy load conditions. As far as the alternator whine goes, I'm not looking to solve that until I solve the issue of these voltage spikes. But, out of curiosity why would I need to take the cap out? Capacitors filter out AC noise when connected in parallel with the system--or so they are supposed to. And my grounds are run through a distribution block.



eisnerracing said:


> Like everyone said sounds like the voltage regulator is bad
> Putting out to much power above 2k
> I see this in old hot rods a lot bad external voltage regulator
> But if this is a new car it's inside the alt.


My issue is not that the voltage is abnormal at any specific rpm, but that it tends to spike very briefly when either: the amount of current draw decreases sharply, or the pulley's rate of spin is increased WHILE the alternator is under significant load. It is as if the regulator is always a step behind. While this could mean that the unit is defective, I am guessing that it is more likely just a limitation of the design.

It seems to me that If I were able to get/build a big enough capacitor bank (I'll have to do some calculations as to just how big), that the spikes could be effectively absorbed until the alternator catches up.


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## eisnerracing (Sep 14, 2010)

The battery should stabilize the spike .. What year car / truck? 
The computers in newer cars may control the voltage output ..
I don't know if a cap bank or a Rockford fosgate 10uf cap would help 
But maybe - strange - have u done the big three? I think I read you did 
Did u find a weird magnet around the power or ground at the battery?? 
If you remove it the computer can't see and correct voltage 
Happened to a few Chevy trucks / taboes I've done audio in


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## Peteman720 (Jan 8, 2013)

eisnerracing said:


> The battery should stabilize the spike .. What year car / truck?
> The computers in newer cars may control the voltage output ..
> I don't know if a cap bank or a Rockford fosgate 10uf cap would help
> But maybe - strange - have u done the big three? I think I read you did
> ...


This system is in a 1996 Honda Accord, so nothing fancy. I have done the big three. I didn't find any magnets, and the voltage is within acceptable boundaries 99.9% of the time, so I doubt that the computer is clueless as to the voltage of things.

I just did some quick calculations and in order to absorb 150Amps of current for a half of a second with only a .5volt change across the system, I will need 150 farads of capacitance. That's a lot, but I saw I guy saying he built a ~300 farad bank for cheap. Or I can just assume that its only 100 amps of current and buy this: Lanzar - VCAP10000 - Vector 100 Farad 16 Volt Hybrid Double Capacitor

Edit: The reason that a battery won't help absorb the spikes is because it stops absorbing current after it is completely charged ~12.6 volts. Or at least thats what I'm assuming.


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## Peteman720 (Jan 8, 2013)

Well it looks like capacitors are pretty expensive.. There wouldn't, by chance, be some way to just bypass the overvoltage protection on the MRX-M240 would there? I'm comfortable with opening it up and doing some soldering if necessary.


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## Peteman720 (Jan 8, 2013)

disabling over voltage protection on amp? - Amplifiers - SMD Forum

This guy seems to be having the EXACT same problem as I am.


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## NJaNeer (Jun 8, 2013)

Peteman720 said:


> The 10.5 volts is the minimum voltage which was reached while starting the car. From what I've read online, anything above 9.6 volts is acceptable under these heavy load conditions. As far as the alternator whine goes, I'm not looking to solve that until I solve the issue of these voltage spikes. But, out of curiosity why would I need to take the cap out? Capacitors filter out AC noise when connected in parallel with the system--or so they are supposed to. And my grounds are run through a distribution block.
> 
> 
> 
> ...



Ok! Thought you said your battery was showing 10.5v while the car was running.. lol

Well, what I can tell from what you told me is you installed a new alt and now have issues with sub amp. Did you have the alt whine before the new alternator? For me, the voltage regulator seems like the culprit. If I remember correcly one of the guys resolved his issue with a external regulator. I know you said yours is not as extreme, but still sounds like the problem. Especially when you say stepping on the gas pedal causes it. 

The reason I say take out the capacitor, because the only thing you would want that thing for is to help with voltage spikes. And it seems like it's not helping. You also said you had a 15+v max to the amp. Well that capacitor might be lowering the actual peak. You could leave the cap and test from the battery or alternator. It would be nice to know your actual peak voltage. Sure you could probably find a capacitor that could help with that, but do you want to risk overpowering your electrical components or battery?


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## Peteman720 (Jan 8, 2013)

NJaNeer said:


> Ok! Thought you said your battery was showing 10.5v while the car was running.. lol
> 
> Well, what I can tell from what you told me is you installed a new alt and now have issues with sub amp. Did you have the alt whine before the new alternator? For me, the voltage regulator seems like the culprit. If I remember correcly one of the guys resolved his issue with a external regulator. I know you said yours is not as extreme, but still sounds like the problem. Especially when you say stepping on the gas pedal causes it.
> 
> The reason I say take out the capacitor, because the only thing you would want that thing for is to help with voltage spikes. And it seems like it's not helping. You also said you had a 15+v max to the amp. Well that capacitor might be lowering the actual peak. You could leave the cap and test from the battery or alternator. It would be nice to know your actual peak voltage. Sure you could probably find a capacitor that could help with that, but do you want to risk overpowering your electrical components or battery?


Any ideas on where to get a hold of an external regulator? I've only looked around for a little but didn't find much. It certainly seems like the problem is being caused by a regulator that is slow to react, but that may not mean it is defective. It may just be the way it is designed.


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## Peteman720 (Jan 8, 2013)

http://www.aeroelectric.com/articles/spike.pdf

Check out page two of this pdf. The author puts the correct technical terms on my situation, although his is occurring on an airplane.

He mentions that usually a battery will hold down the spike. Perhaps I'll just get a new/second battery? I really don't want to waste my money though. I just had my battery looked at at the local auto parts store and they said it tested good.


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## NJaNeer (Jun 8, 2013)

Peteman720 said:


> http://www.aeroelectric.com/articles/spike.pdf
> 
> Check out page two of this pdf. The author puts the correct technical terms on my situation, although his is occurring on an airplane.
> 
> He mentions that usually a battery will hold down the spike. Perhaps I'll just get a new/second battery? I really don't want to waste my money though. I just had my battery looked at at the local auto parts store and they said it tested good.


Hey Pete,

Well at least we are learning something 
Ok, so I know you said these alternator people won't help you?
I want to know what brand so I don't buy one!! lol

Will the second battery fill up and you are stuck in the same place?
It seems to me a second battery would only help with playing music with the car off.
From what I gathered about external voltage regulators is that you would rather have the internal, but you can bypass them with a external. I believe I saw some posts that said you can find them at local auto parts store.
That could always be an option, cause I think they are pretty cheap ($20-30) I feel like you should have a warranty on that new alt and they should be fixing this for free


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## Peteman720 (Jan 8, 2013)

NJaNeer said:


> Hey Pete,
> 
> Well at least we are learning something
> Ok, so I know you said these alternator people won't help you?
> ...


Yeah I'm trying to figure out exactly how a battery behaves when it is presented a voltage higher than its fully charged voltage. Perhaps it does still have to ability to store and release power at that point? I'm not sure.

The alternator I bought is a Load Boss alternator, and other than the spikes it seems to be performing excellently. Definitely stronger than the stock alt. I don't think the spikes are due to the unit being defective. I think it is just a poor design which only causes problems in very specific cases. Nothing other than that one amp even flinches at the spikes.


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## NJaNeer (Jun 8, 2013)

Looks like they have a warranty, I would at least give it a shot. I have seen some decent reviews of that alternator so you shouldn't be having this issue. If they are not willing to send you a new one or replace the regulator maybe they will send you an external regulator for free? This will probably be the cheapest route.

1. Buy new batteries until you have enough to stop the spike. Could get expensive lol
2. Buy new amp and hope it doesn't shut down.
3. External voltage regulator
4. Disconnect protect mode from amp. Wouldn't even risk for the chance of fire.
5. Get that warranty going and get one that has a steady output


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## Peteman720 (Jan 8, 2013)

Yeah I was thinking about a new amp. That might almost be the way to go however it would be hard to sell the one I have because I can't really demo it.

Anyone have any references as to how batteries act as system voltage exceeds fully charged voltage?

Edit: But if I wanted to disable the protect mode, how would I go about it? I haven't been able to find any schematics on the thing.


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## Peteman720 (Jan 8, 2013)

Another useful article. I didn't read the whole thing quite but it seems to talk about suppressing spikes from "load dumps"..

http://www.industrologic.com/autotransients.pdf


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## eisnerracing (Sep 14, 2010)

That may be hard to bypass but if you contact 
Alpine they may send you a full layout of the amp. 
And 100uf cap scares me a bit - I've seen cap banks 
Explode in the past 23 yrs . I know now with hybrid
Caps it's not as likely . Have you thought of maybe adding a battery isolator 
And running a second battery ? Or just adding a second battery
Connect power to rear battery for primary power to amps.


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## Peteman720 (Jan 8, 2013)

I've been looking at all sorts of voltage stabilizers for cars and none of them seem to have much merit. They all seem to be tiny little modules filled with several small capacitors--not enough storage to absorb any significant spikes. As to why none of them would instead just create a direct short across the battery during the split second of voltage overload I dont know...


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## Peteman720 (Jan 8, 2013)

eisnerracing said:


> That may be hard to bypass but if you contact
> Alpine they may send you a full layout of the amp.
> And 100uf cap scares me a bit - I've seen cap banks
> Explode in the past 23 yrs . I know now with hybrid
> ...


I will shoot Alpine an email then..
I am trying to look into what the effects of a second battery or a larger battery would be. I don't actually need more energy storage capacity because my alternator can supply enough power to drive my system at 14 volts. I know another battery will present the alternator with more load, but I don't know exactly how good batteries are at filtering out spikes way above their fully charged voltage. Do lead acid batteries have much storage capacity above their rated voltage? Or is it another characteristic which would filter out the spikes?


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## NJaNeer (Jun 8, 2013)

So what's the verdict? Interested to see if you solved the problem.


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## Peteman720 (Jan 8, 2013)

NJaNeer said:


> So what's the verdict? Interested to see if you solved the problem.


Well I contacted Alterstart about my issue and they offered to replace the unit. So, I put the old alternator back in and am now awaiting a replacement. With the old (stock) alternator, the voltage spikes are gone and everything is running as it should; but I just don't have quite enough power.

On a side note, Alterstart has offered me excellent customer service--far above and beyond what I expected. They were even willing to ship out the new unit once I provided them with the tracking number proving I was returning the old one (no deposit or anything!). Despite some negative reviews I've read, I am so far happy with my experience. Defective units cannot be completely eliminated and Alterstart has made obtaining a replacement quick and painless. Don't hesitate to buy a Load Boss alternator if you're running on a budget.


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## NJaNeer (Jun 8, 2013)

Peteman720 said:


> Well I contacted Alterstart about my issue and they offered to replace the unit. So, I put the old alternator back in and am now awaiting a replacement. With the old (stock) alternator, the voltage spikes are gone and everything is running as it should; but I just don't have quite enough power.
> 
> On a side note, Alterstart has offered me excellent customer service--far above and beyond what I expected. They were even willing to ship out the new unit once I provided them with the tracking number proving I was returning the old one (no deposit or anything!). Despite some negative reviews I've read, I am so far happy with my experience. Defective units cannot be completely eliminated and Alterstart has made obtaining a replacement quick and painless. Don't hesitate to buy a Load Boss alternator if you're running on a budget.


I'm glad to hear that you decided to contact them, and that's awesome that they are going to replace it for you (as they should with a warranty). Let me know how it works out for you. Are you getting any alternator whine with the stock alternator?


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## Peteman720 (Jan 8, 2013)

NJaNeer said:


> I'm glad to hear that you decided to contact them, and that's awesome that they are going to replace it for you (as they should with a warranty). Let me know how it works out for you. Are you getting any alternator whine with the stock alternator?


Well actually yes, I am still getting the same old whine. I actually just started a new thread on it after looking further in to the issue tonight: http://www.diymobileaudio.com/forum...tackle-some-alternator-whine.html#post1938385


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## Peteman720 (Jan 8, 2013)

Sorry for the long delay, I have been very busy with work lately and have only just recently had time to install the replacement unit.

I put the new alternator in after receiving it promptly and wahlah--no more voltage spikes. Everything is behaving normally and I can definitely tell that the alternator is putting out more current than the old stock unit. 

I was actually rather surprised with the quality of service that I received from Alterstart. I read reviews online and many of them seemed to be negative. Some reviewers scoffed at Alterstart's claim that the alternator will not reach full output until 8000 rpms since most automobiles will redline before that point. Yet, the manual explicitly states that the pully ratio must be taken into account when looking at such numbers.

I've had a good experience, so don't think that they are just a bogus company.


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## NJaNeer (Jun 8, 2013)

Peteman720 said:


> Sorry for the long delay, I have been very busy with work lately and have only just recently had time to install the replacement unit.
> 
> I put the new alternator in after receiving it promptly and wahlah--no more voltage spikes. Everything is behaving normally and I can definitely tell that the alternator is putting out more current than the old stock unit.
> 
> ...


Glad to hear that you resolved the problem. Did that fix your alternator whine?


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