severe voltage drop, bad alternator?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=85333
Printed Date: April 27, 2024 at 5:42 PM
Topic: severe voltage drop, bad alternator?
Posted By: astro88
Subject: severe voltage drop, bad alternator?
Date Posted: November 08, 2006 at 12:58 PM
The car is a 92 z34 stock alternater(105 amp)
The system is kicker kx1200 running two re se 10s.
zapco ag200 running components
Alpine 9815 h/u
All 4 awg wiring to amps and grounds.
Ive upgraded the grounds ,battery to bdy, battery to engine,i havent done the alt to battery(those that know the z34 know why).
When i have the system running moderately the lights dim very badly,if i push it really hard the car will actually stall!
with system off im reading 13.8-14.3 at the amp,when i push it hard the voltage drops down to low 11s when the bass hits.
I had a 1 farad lightning audio cap in there(which i removed today to see if it was helping or hurting)and its worse now than b4.
I know 4 awg is pushing it for a kx 12oo but i had one in another gm 2 years back ,all 4 awg as well with no issues at all.
Any input is welcomed thanx.
Replies:
Posted By: forbidden
Date Posted: November 08, 2006 at 1:44 PM
Bad alternator, bad battery quite possibly as well, bad ground (read the grounding sticky) and you should be using a 2 or 0 gauge wire ideally. Meter the voltage at the alternator, what does it show?
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Top Secret, I can tell you but then my wife will kill me.
Posted By: Alpine Guy
Date Posted: November 08, 2006 at 1:58 PM
I would have to say old alternator being hit with an impossible task. Even if the alternator was brand spanking new, you would have the same problem, you need to upgrade that alternator. You need at least a 150 amp alternator, 180 amp would be perfect and anything better is, well, better.
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2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
Posted By: astro88
Date Posted: November 08, 2006 at 2:13 PM
forbidden wrote:
Bad alternator, bad battery quite possibly as well, bad ground (read the grounding sticky) and you should be using a 2 or 0 gauge wire ideally. Meter the voltage at the alternator, what does it show?
I checked the voltage drop at the battery as well as at the amp,it read pretty much the same.
As for checking at alternater.....on the z34 the alternater is mounted low on the 3.4l engine which makes it near impossible to get to.
i did try to put a new wire on it from the wheel well area but i ran out of patience(and bandaids!)
I know 105 amps is pretty lacking for this amp,but im really not pushing it that hard and the dimming and stalling just really seems excessive.
The alternater in like 1.5 years old the battery is about 1 year old.
My grounds are all clean and scrapped of paint,ive tried different ground locations in the trunk,all with the same outcome.
I want to rule out any connection/ground issues before i look into buying a new alternater.
would a upgrade of the alternater wire to battery make a huge difference or should i just upgrade the alternater and wire at the same time?
I just dont wanna take the alternar out to change the wire and not fix the problem,its like a 8 hour job to change them is these cars!
Thanx for the input so far
Posted By: Mad Scientists
Date Posted: November 08, 2006 at 2:21 PM
Have the alternator output checked.. not just voltage, but amp output also. Also measure AC voltage at the battery.. see if there's any. What it sounds like to me is either a weak alternator or you're pulling more amps then you think. Jim
Posted By: astro88
Date Posted: November 08, 2006 at 3:22 PM
Mad Scientists wrote:
Have the alternator output checked.. not just voltage, but amp output also. Also measure AC voltage at the battery.. see if there's any. What it sounds like to me is either a weak alternator or you're pulling more amps then you think.
Jim
I will check the ac voltage at battery, and how do i check output amps? withh dmm or do i need to take it to a garage?
More amps thani think? are you saying possibly a amplifier problem?
My gain on my amp is at about 10-11 o'clock sub out is set to +15 as im told to set it to (alpine 9815)
Posted By: astro88
Date Posted: November 08, 2006 at 3:47 PM
Ok on my dmm i have it set to acv at 200,is this correct setting for ac voltage?
Anyways its reading 30.8 with engine running when i turn up the system it dips to 27.5-28.2
at the same time the 12v voltage dips from 14 to low 12s
with engine off the gattery ir reading near 13v and the ac voltage is sitting at 28.0.
the dmm i have is called equus model #4320 if it matters?
Posted By: Mad Scientists
Date Posted: November 08, 2006 at 5:38 PM
I'm trying to help you determine if the alternator is outputting its rated output and you're drawing more than that, or if the alternator is weak and not outputting its rated output. The AC measurement is to check for a shorted diode in the alternator.. The current output of the alternator needs to be checked with a clamp on ammeter.. if you don't have one, you'd need to either go to a shop, or find a friend with out. Jim
Posted By: sedate
Date Posted: November 08, 2006 at 5:50 PM
Huh.
Okay there isn't anything wire is going to do for your at this point. You have two *enormous* amplifiers and a 14 year old charging system.. that.. if you stop with this torture now.. you should be able to preserve in working order. But, seriously, lay off the stereo until you have another battery in your car or you might just fry out the alternator you have. (I destroyed a stock AC Delco alt in 3 days by adding a JL monoblock to my old car.)
I'm not really with the "bigger alternator or nothing"-crowd that usually frequents this forum. I would first try a true Deep Cycle battery, and see if that doesn't put enough of a buffer between your amps and your car.
*My* method of solving your problem would be to take *two* Optima Yellows and wire them directly together.. but you kinda have to buy them at the same time... there are some hardware issues here as well as far as termination rings and blocks and such.. (and a relay if you want to get fancy and disconnect the batts when the car is off) but for about $400 (well less than a new, higher capacity alt) you could wire them together, in parallel, with one in your engine and the other in your trunk. You get a much bigger reserve for your amps, and, by moving a battery right next to the amps and another one right next to your headlights, you'll find headlight dimming should be all squared away.
And you need to bite the bullet and run a wire from your + post to your battery. But don't even bother without some real power capacity between your car and your amps.
As far as another alternator goes.. that is probably the best bet in the end, but you would still get excellent results adding a new, preferably deep cycle battery in the car to support amps that ridiculously massive. I mean really dude. That is like... what? 1600 watts RMS?
Anyway, if you are going to go with an alternator, to make those worthwhile, in my experience, really requires some quality and money put into them.. by a Stinger or something of that nature.. I've had several alts rewound and have never had a satisfactory one... always like 9v output at idle and crap like that. Stick with big, expensive name brands for an investment like that.
I'd do the batteries.
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"I'm finished!" - Daniel Plainview
Posted By: sedate
Date Posted: November 08, 2006 at 5:58 PM
Mad Scientists wrote:
I'm trying to help you determine if the alternator is outputting its rated output and you're drawing more than that, or if the alternator is weak and not outputting its rated output.
What?! Of course he's drawing more than that. For gawd sakes he's got like two enormous amps in that little car. Isn't a z34 like a Cavalier or something?!
That Kicker amp alone should bury his alt nevermind the Zapco. He'd need all 105 amps just to meet that 1200watts of output.. nevermind another 10-30% in amp overhead. THEN add ANOTHER amplifier.. Zapco's are really beefy amps.. so he's probably, when he's pushing it, asking like 150 - 180amps off a battery that he has not indicated that he has upgraded at all.
Oh boy. All the caps and wires and multimeter prodding in the world are not going to help here. See above.
------------- "I'm finished!" - Daniel Plainview
Posted By: sparkie
Date Posted: November 08, 2006 at 6:36 PM
I would recommend that you replace the alternator with a high output unit. Adding batteries will only create more of a load on the already stressed alt. The main purpose for a battery is to supply enough current to the starter motor to start the car. Once this is done, the battery has finished its job and depends on the alt to recharge it. All the accessories in the car (radio, ignition, heater, etc.) run off the alternator's output. The only other thing the battery does is to help filter the DC output from the alternator and help with any serious current draw from the car when the engine idle is low. Your alternator was never designed to power the car and a huge stereo system even when the car was new. You need to upgrade your power supply system to the stereo and car. This should have been done first. You should also in the mean time check the ground cable from the battery to the body. They are know to corrode at the body connection.
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sparky
Posted By: astro88
Date Posted: November 08, 2006 at 6:50 PM
ya the battery is an interstate direct replacement....its nothing special.
Actually the z34 is a lumina,youre thinking of a z24 cavaleir(its little bit bigger)thats all.
The zapco amp is just 50wrms per channel.
Theres like no room under the hood to put a big battery the one thats in there is buried as it is.This ncar is not stereo friendly at all!
I think im gonna rewire my subs to load the amp to 4 ohms instead of the 1 0hm ive got it at now.
Im not gonna get 1200rms out of it but im sure as doodie not getting it right now anyways.
Last thing i wanna do is break down in the winter....
I will go by the shop and get my voltage output checked mad scientist,..i understood what youre sayin.
Posted By: astro88
Date Posted: November 08, 2006 at 9:30 PM
mad scientist....the ac readings i got,what do they mean?
Posted By: sedate
Date Posted: November 09, 2006 at 3:00 PM
sparky wrote:
Adding batteries will only create more of a load on the already stressed alt.
WHERE does this come from? The BATTERY runs your car, the alternator charges the battery. Give yourself huge batteries and you 'filter' the huge grabs for power that a NAPA battery cannot handle when it's supplied by a stock alternator.
sparky wrote:
The only other thing the battery does is to help filter the DC output from the alternator and help with any serious current draw from the car when the engine idle is low.
Help with serious current draw? Like running a stereo? So a larger battery would help?
astro88 wrote:
I think im gonna rewire my subs to load the amp to 4 ohms instead of the 1 0hm ive got it at now.
That ought do it..
------------- "I'm finished!" - Daniel Plainview
Posted By: sparkie
Date Posted: November 09, 2006 at 4:34 PM
I'm sorry Sedate, but the battery does not run the car. If that were true you wouldn't be able to disconnect the battery while a vehicle was running. The cars electrical system is powered by the alternator. You may want to research this a little more to learn how a vehicles electrical system works.
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sparky
Posted By: sedate
Date Posted: November 09, 2006 at 5:25 PM
Okay I'm seriously not trying to pick a fight but ppl giving advice like yours cost me like a year and $500 screwing with my electrical system when I was wayy to poor to do it.
sparkie wrote:
If that were true you wouldn't be able to disconnect the battery while a vehicle was running.
WHAT CAR do you drive?! I've NEVER heard of this; disconnecting the battery in ANY car I've ever had will shut it off immediately. I'm not even kidding.. I got a huge settlement from Firestone when they didn't reconnect a battery cable and my car shuttoff on the highway. I guess.. the circuit isn't exactly cut when you disconnect the battery.. but you remove all capacitance from the thing and alternators are so squirrly you'd fry your car out *easy*... I couldn't imagine a car's ecu letting the thing run w/o a battery. Maybe its an import thing.. I dunno. But I've NEVER heard of a car running w/o the battery connected... and I can assure you Toyota's, Mitsubishi's, and Subaru's (made in the last 10 years) do NOT run like that.
sparkie wrote:
The cars electrical system is powered by the alternator.
I think the more pragmatic statement would be "The car's electrical system is run by the battery, which is charged by the alternator." I would argue either is accurate. Again, which is why I come back to a paralleled, dual battery setup. It is what I've had the *best* results installing in several applications with symptoms very similer to the original posters'.
------------- "I'm finished!" - Daniel Plainview
Posted By: wirewise
Date Posted: November 09, 2006 at 5:36 PM
Actually on older model vehicles (domestic and import) without computers you could start the vehicle and remove the battery and the vehicle would continue to run. Sparkie is correct when he says the primary purpose of a battery is to start the vehicle. And no, the vehicle does not run off the battery, however todays vehicles (with computers) do require the battery to be connected to run.
~wirewise~
Posted By: sparkie
Date Posted: November 09, 2006 at 6:08 PM
Thank you wirewise. Please understand Sedate that I don't want any fights or arguements either. I hope there are no hard feelings. Ideally Astro88 you need to consult an installer in your area that has the tools and knowledge to properly check out your whole system. That way they can make sure that your system is wired properly and safely. It's no good to have great stereo and not be able to enjoy it. There are many different factors that play into your senario as most members have mentioned. Trying to solve all of them without the car present is beyond anyones ability.
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sparky
Posted By: sedate
Date Posted: November 09, 2006 at 6:21 PM
*Deep Sigh*
Okay.
wirewise wrote:
Sparkie is correct when he says the primary purpose of a battery is to start the vehicle.
Right.. NOT with a HUGE stereo installed. The idea of a car coming out the factory with a nice shiny SLI battery under the hood is exactly that.. the primary purpose of the battery is to light the dome and make the car start.
Installing a pair of giant amplifiers changes the .. 'design goals' of the electrical system.. now the battery needs to not only start the car, but the far more demanding task of keeping up with a giant monoblock.
So.. in effect, the primary purpose of the battery(ies) is no longer "starting the car" and keeping in line with that thinking, we can look at other solutions that, as the original poster implied as desirable, would not involve replacing the alternator.
wirewise wrote:
And no, the vehicle does not run off the battery
..I really could argue the semantics of this *all* day.. ------------- "I'm finished!" - Daniel Plainview
Posted By: wirewise
Date Posted: November 09, 2006 at 6:44 PM
Adding amplifiers does not change the design of the electrical system and only changes the users "goals of the design" rather than the "design goal" of the electrical system. Adding amplifiers or any other accessories adds an additional load to the existing electrical system. To maintain the intergirty of the electrical system, the alternator should be upgraded if it no longer meets or exceeds the demands of the entire load placed on the system. Adding more or larger batteries is really only a band-aid for the additional load placed on the existing electrical system once it has exceeded the output of the alternator. Yes, it will appear to solve the problem at first, but eventually the system will fail. Feel free to argue all you like, but it will not change this fact.
~wirewise~
Posted By: sparkie
Date Posted: November 09, 2006 at 7:01 PM
The great thing about this site is you can learn new things even if you have been doing for a very long time like me. Someone once said that there is no such thing as a wrong answer, only a well supported answer.
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sparky
Posted By: astro88
Date Posted: November 09, 2006 at 7:49 PM
Well i rewired the subs to be at 4 ohms and it sucks big tim!
i need to do some upgrades cause i need more bass lol,i never bought a 1200w amp just to run 300w!
And still turning up the volume with this set up i get dimming,not really bad but still present,gonna have to look into a new alternator around 200amp.
Thanx everyone for youre advice.
Posted By: sedate
Date Posted: November 09, 2006 at 7:58 PM
wirewise wrote:
Feel free to argue all you like, but it will not change this fact.
I take your leave to argue. Sometimes I get scared on this board.
wirewise wrote:
Adding more or larger batteries is really only a band-aid for the additional load placed on the existing electrical system once it has exceeded the output of the alternator. Yes, it will appear to solve the problem at first, but eventually the system will fail.
Okay. I think I figured this guys current draw to be like.. factoring amp overhead, a solid 150amps. At a 105amp alt, i dunno, 25-50% of which goes to the vehicle proper..this does leave a rather enormous power deficit. Of course.. this rests on the obviously incorrect assumption that power draw will *always* be 150amps + what the vehicle needs. A *constant* pull of 200+ amps would of course overwhelm a stock alt backed by *any* amalgamation of batteries in short order. This is however, is not typical behavior of a monoblock amplifier. The nature of dynamic music would only require such output.. every.. I dunno.. sayy.. 1/2 of a second, every other second. So 75% of the time the alternator is *well* above what the system requires for optimum output.
SOOOO ... utilizing larger batteries... which, on the whole, net more or less what they release, and are less susceptible to interminent voltage drop-off than the stock SLI batteries, is a highly competetive solution to the original posters' problem. ------------- "I'm finished!" - Daniel Plainview
Posted By: stevdart
Date Posted: November 09, 2006 at 9:23 PM
Huh.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: astro88
Date Posted: November 09, 2006 at 9:29 PM
Originally i had a dual 4 ohm L7 hooked to this amp with 600wrms coming from the amp i had no big dimming problems.
I put in the re's and loaded the amp down to 1 ohm and at first it was pumping nicely for like 5 minutes.
I shut the car off and when i went out like 3 hours later it was weak and the voltage drops got real bad.
Now i have it loaded to 4 ohms so 300rms and now its dimming still....almost as bad as it was at 1 ohm,noticeable clipping too.
Could i have messed up my amp? Im still leaning towards a bad alternator cause even when i put the blinker on my dash lights dim now.
I will take it to the shop and have the amperage checked in the next couple days.
Posted By: druidpagen
Date Posted: November 09, 2006 at 10:25 PM
actually you weren't drawing as much amps as you thought. i did some calcs and you were running about 105 amps and probaly peaking slightly over that. wich is your problem.,your alternator was constantly recharging your your bat. runnning 4 ohms (300 watts) is like burning $ and a wast! eather way your gonna have to spend some cash to get up to optimal performance. earlier posts had some good sugestions. *add another alternater (or stronger one), battery or both. wich would probably be the more expensive aproach but will let you run your 1200 watt set-up. *sell your subs and get 2- 4ohm subs wired to a 2 ohm load and run 600 watts wich would draw around 66-75 amps giving you some head room. this would probably be cheaper than option 1. unfortunetly your hot load probably ruined your alternator (wich im almost positive) being an installer and mechanic. which is probably the problem right now. your battery is probably ok unless you ran your first set-up for a long time or ran it dead. if you ran it dead pitch it. autozone can check your battery for free so atleast that's one cheap thing. good luck
Posted By: wirewise
Date Posted: November 10, 2006 at 10:07 AM
sedate wrote:
wirewise wrote:
Feel free to argue all you like, but it will not change this fact.
I take your leave to argue. Sometimes I get scared on this board.
wirewise wrote:
Adding more or larger batteries is really only a band-aid for the additional load placed on the existing electrical system once it has exceeded the output of the alternator. Yes, it will appear to solve the problem at first, but eventually the system will fail.
Okay. I think I figured this guys current draw to be like.. factoring amp overhead, a solid 150amps. At a 105amp alt, i dunno, 25-50% of which goes to the vehicle proper..this does leave a rather enormous power deficit. Of course.. this rests on the obviously incorrect assumption that power draw will *always* be 150amps + what the vehicle needs. A *constant* pull of 200+ amps would of course overwhelm a stock alt backed by *any* amalgamation of batteries in short order. This is however, is not typical behavior of a monoblock amplifier. The nature of dynamic music would only require such output.. every.. I dunno.. sayy.. 1/2 of a second, every other second. So 75% of the time the alternator is *well* above what the system requires for optimum output.
SOOOO ... utilizing larger batteries... which, on the whole, net more or less what they release, and are less susceptible to interminent voltage drop-off than the stock SLI batteries, is a highly competetive solution to the original posters' problem.
A 105 amp alternator, or any other for that matter, does not continuously put out a 105 amps of current. Alternators only put out as much as is demanded from them up to their respective rating. Averages mean nothing with regards to the maximum load placed on an alternator. Once the maximum load exceeds the output rating of the alternator, any one of the three sets of rectifying diodes are in danger of being destroyed. For each one of these that fails, maximum output is reduced by a third. And yes, adding more batteries will put an additional load on the alternator. BTW, there's nothing to be scared of on this board, unless of course you fear learning something new ;) ~wirewise~
Posted By: astro88
Date Posted: November 10, 2006 at 1:11 PM
Went to the alternater shop today and got the system checked and its working like it should?
Can anyone reccommend a good place to order a ho alternater
that will ship into canada,or preferably one that IS in canada?
Posted By: kicker guy
Date Posted: November 10, 2006 at 1:22 PM
Generally I don't like to recommend ebay but i like Iraggi alts
Posted By: sedate
Date Posted: November 11, 2006 at 1:02 AM
wirewise wrote:
And yes, adding more batteries will put an additional load on the alternator.
See... even if.. somehow.. this is true.. which.. I suppose it would be in .. in a way.. I'm just not sure I understand why it would even matter in this application. The idea is "Get my amps to work" ... adding huge power capacity will accomplish this.. and do no harm to the batteries or the electrical system..
Would you agree that adding paralleled deep cycles by themselves isn't going to cause catastrophy to the car? Would you agree that all other things being the same, doing that would have absolutely no effect on vehicle operation what-so-ever?
Soo.. if you had a deep cycle.. in my scenario, the ubiquitous Yellow Top.. that can put out like 25 amps for a solid hour before it drops under 12v.. and then have two of them.. right? Then attach a power supply that at most would supply like half of all the power that that car could possibly need.. an operating alternator.
So attached to this you are asking intermitent 150 amp pulls and this is going to somehow fry out batteries with that sheer amount of storage?! Nevermind batteries that can physically withstand the huge power drains that are actually being asked of it?
wirewise wrote:
Once the maximum load exceeds the output rating of the alternator, any one of the three sets of rectifying diodes are in danger of being destroyed. For each one of these that fails, maximum output is reduced by a third.
This is absolutely correct. So.. wouldn't it be desirable to keep huge loads *away* from the alternator and on Deep Cycle batteries that are made for such abuse? Electrical generators off all kinds like thier loads constant.. so wouldn't having a real battery between the alt and the amps be desirable.. regardless of alternator output?
Which brings us back to the original poster.
astro88 wrote:
Now i have it loaded to 4 ohms so 300rms and now its dimming still....almost as bad as it was at 1 ohm,noticeable clipping too.
Could i have messed up my amp? Im still leaning towards a bad alternator cause even when i put the blinker on my dash lights dim now.
Yea you killed your battery. You (sort of) indicate that you had your electrical system checked, but you might want to remove the battery and do that one on its own. See.. what happens to SLI batteries when you ask that kind of power outlay is very similer to what you describe here.. blinker causing light dimming and such. While the battery reads 12v at the poles and can sort of start the car.... any actual load beyond the 20 or 30 or so amps it takes to start the car brings total failure to the electrical system as it instantly brings the system down to unmanagable single-digit voltages from the warped, corrupt battery. A properly functioning alternator, which you won't have for long if you don't LAY OFF THE AMPLIFIERS UNTIL YOU GET SOME REAL BATTERIES, will *NOT* always properly power a vehicle when the battery is corrupt..
Again.. the battery was DESIGNED to start the car and then run on the alternator. (I guess I'll concede that) But you asked it to run ENORMOUS amplifiers and you need a battery(ies) that can stand up to that sort of abuse... REGARDLESS of alternator output... particularly with amplifiers of this size. ------------- "I'm finished!" - Daniel Plainview
Posted By: astro88
Date Posted: November 11, 2006 at 5:18 PM
Changed out the battery today with a new one that was in my other car its an ac delco, its only 650 cca theres absolutely no room under the hood for a bigger battery! i tried to fit a eliminater 1000 cca in there and there was no bloody way!Anyways there was no change at all.
Car has been starting no problem the whole time,with this batt and the last one.
Myself i can see the use of the extra more powerfull batterys to help supply the extra current draw but what im thinking is that as the power is being sucked from them wouldnt i still be relying on my weak ass alternater to recharge them? A job it seems its not capable of doing it seems.
What i will do is try to find a yellow top for my car that fits and go from there,im looking into a new alternater but if its way too much money lol im selling this car! haha
Posted By: sedate
Date Posted: November 11, 2006 at 8:03 PM
astro88 wrote:
Changed out the battery today with a new one that was in my other car its an ac delco, its only 650 cca theres absolutely no room under the hood for a bigger battery! i tried to fit a eliminater 1000 cca in there and there was no bloody way!
By 'Bigger' I mean a Yellow Top or comparable Deep Cycle battery for high-load applications.. the physical size of the battery is largely irrelevant. What is important here is the internal construction of the battery... it must be able to not only store large amounts of current, but, (and here is where your stock-type batteries fail) withstand the huge abuses of a constant 50 - 150 amp drain for longer periods.
The really important thing isn't so much ultimate storage capacity, but the batteries physical ability to deal with large loads, and multiple charges/discharges.. loads that oem-replacement type batteries cannot handle.
astro88 wrote:
Car has been starting no problem the whole time,with this batt and the last one.
I betcha that the original battery may hold 12v at its poles but putting any sort of load to it totally craps it out. It not only fails to charge past a small fraction of its original capacity, but past starting your car it is for all intents and purposes dead. Just my thinking.
astro88 wrote:
Myself i can see the use of the extra more powerfull batterys to help supply the extra current draw but what im thinking is that as the power is being sucked from them wouldnt i still be relying on my weak ass alternater to recharge them? A job it seems its not capable of doing it seems.
I'm not sure what test your shop ran, but I'm not convinced your alternator is working properly after originially subjecting it the amps you have with only a stock SLI battery behind it..
Like... very quickly (within minutes, I imagine) upon firing up your new amplifiers you drained off your original battery (at this point light dimming and intermintent monoblock shuttoffs were now occuring) and now were pulling from the alternator directly.. while the huge gaping hole in your electrical system that was your battery, now at 8v or so, interupts what little current is actually there... you probably damaged your alternator asking such huge pulls from it and the SLI battery never had a chance against your monoblock...
Ultimately, the goal is to show the car a constant charge of 12v.. to the amps and the rest of the vehicle... an oem alternator putting out 100amps or so ought be sufficent ... but ONLY when backed by batteries that can, on their own, maintain amplifiers for at least SOME time... again.. music is dynamic and your amps are not going to be even close to thier maximum output/current draw ALL the time.. assuming you spend sometime in the car NOT blasting your eardrums out of existence or at relaxed listening volumes. As long as the batteries maintain a charge of 12v, which they WILL DO under the load of those amps, particularly backed by an operating alternator, you will NOT experience the power failures that you were experiencing.
I will concede however, that a dedicated effort to run off the batteries, even in the face of an idling car, will do so. Eventually, assuming you're playing like a tone CD or something and can keep your monoblock running red-hot all the time, you ought be able to knock my suggested setup out of commission... but for everyday, real world use, I'd hazard you will not find a more economically competetive solution..
Even if you do add a high-output alternator, which is, ultimately, not a bad idea (again, research this purchase EXTREAMLY carefully.. I've bought 3 different rewound alts from 3 different ppl and never had ONE of them put out more than 10v at idle) you will still require a proper deep cycle battery to maintain any semblence of system reliablity.
------------- "I'm finished!" - Daniel Plainview
Posted By: Alpine Guy
Date Posted: November 11, 2006 at 9:11 PM
"Even if you do add a high-output alternator, which is, ultimately, not a bad idea (again, research this purchase EXTREAMLY carefully.. I've bought 3 different rewound alts from 3 different ppl and never had ONE of them put out more than 10v at idle) you will still require a proper deep cycle battery to maintain any semblence of system reliablity." That right there is where your assumption of an alternator wont do anything. When you get an alternator re-wound in a stock case there isn't much room to play with so something has to be compromised, aka the idle output.. If you purchase a quality alternator (at least $1 per amp) you wont have that problem. I have always spent good money $300-$400 on alternators and have achieved excellent results. With my mechman alternator I could sit at a stop light with the bass cranked on a bass cd and not get light dimming. (3000WRMS System) Now, as for your missunderstanding on how adding more batteries is the answer that is very wrong. If you have time to do so I would study some electrical characteristics, for example how a capacitor charges and discharges in a rectified AC circuit. A battery can only charge to its source voltage (the alternator), If the alternator is only putting out 10 volts, your battery will NEVER read more than 10 volts, its simple fact. No matter how many batteries you install, heck, say you install 50 deep cycle batteries in a veh and crank that bass with a bass track on repeat and go on a road trip for a few hours, I am willing to bet that the car wont start after you turn it off. An extra battery will only help in 2 situations 1) as a current source for when the veh is turned off, or 2) as buffer or filter when the charging source is able to supply more than the demand. Im sure fellow Electrical Engineer's on here can provide a more detailed explaination if you request, were all here as a hobby to help educate and learn, I was once in your position and now im here with only 2 more years of school left and I'll be making the amps people on this site will be frying. ------------- 2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
Posted By: sedate
Date Posted: November 11, 2006 at 11:50 PM
Alpine Guy wrote:
That right there is where your assumption of an alternator wont do anything. When you get an alternator re-wound in a stock case there isn't much room to play with so something has to be compromised, aka the idle output.. If you purchase a quality alternator (at least $1 per amp) you wont have that problem. I have always spent good money $300-$400 on alternators and have achieved excellent results.
*Ahem* Actually, if you read my original post in this thread, you would find that this is not at all my assumption, and I did indeed recommend a larger alternator, albiet from a manufacturer like Stinger, or perhaps Mechman as you suggest, to replace his alternator. I would not spend so little on an alternator after my experience with rewound alts.. price quotes for vehicles I've looked at typically are two or three times your above estimate for a quality manufactured alternator. Typically, they have also required expensive and cumbersome mounting brakets as well as moving other things around in my engine to get them to fit.
The orginal POSTER stated that he can't get to his alt to run the + --> battery wire, if this is the case, he is CERTAINLY going to have trouble swapping the thing.. nevermind the irritating cost of such a componet. I was attempting to provide the original poster with an excellent method of solving his problem, while maintaining his ability to actually implement the solution; as larger/more batteries are far easier to install than a new alternator, and, of coures, represents far less in capital outlay. And I maintain he would require a deep cycle battery for optimal system performance.. w/ or w/o an HO alt.
Alpine Guy wrote:
With my mechman alternator I could sit at a stop light with the bass cranked on a bass cd and not get light dimming. (3000WRMS System)
REALLLY??
Sooo.. assuming your amplifiers are perfect machines and output 100% of the power they get (which they don't), you are using 200 - 240 amps of current. So on a 180amp alt (your sig) you using your... wait what... this can't be...
your battery to filter the extra current draw?
Is that what is happening in your car?! I can't believe it! So I am, indeed, correct in everything I've told our poster?!
I thought so.
Alpine Guy wrote:
Now, as for your missunderstanding on how adding more batteries is the answer that is very wrong. If you have time to do so I would study some electrical characteristics, for example how a capacitor charges and discharges in a rectified AC circuit.
Again, you are totally unable to point out where my "misunderstanding" lies. You are just telling me I'm wrong when all my observations, study, and experience dictate otherwise.
Alpine Guy wrote:
A battery can only charge to its source voltage (the alternator), If the alternator is only putting out 10 volts, your battery will NEVER read more than 10 volts, its simple fact.
Which is the underlying problem with an alt that does not produce proper voltage at idle. I never contradicted this or explained otherwise.
Alpine Guy wrote:
say you install 50 deep cycle batteries in a veh and crank that bass with a bass track on repeat and go on a road trip for a few hours, I am willing to bet that the car wont start after you turn it off.
This belies common sense and doesn't really matter anyway in the application I'm discussing. I already acknowledged that if you make a dedicated effort to overrun the batteries, the attempt would be successful. For normal vehicle operation however, assuming his listening habits are not what you just described (whose are?), larger energy capacity WILL solve this posters problem, if done in the right way. I'm assuming the stereo will not be at maximum output at all times of vehicle operation. Arguing otherwise would just be silly.
Alpine Guy wrote:
An extra battery will only help in 2 situations 1) as a current source for when the veh is turned off, or 2) as buffer or filter when the charging source is able to supply more than the demand.
No, no. Using to Ohm's Law and simple math, we can confirm that indeed, the battery can also be used "as buffer or filter when the charging source is unable to supply more than the demand."
We can prove this by simple observation.
In this case we would observe you, in your car, at a stoplight, listening to your 3000wrms/200-some-amp stereo off your 180 amp alternator that is seeing idle speed at its crank, so its really making something like 100 amps.
How's that? Your BATTERY.
Alpine Guy wrote:
Im sure fellow Electrical Engineer's on here can provide a more detailed explaination if you request
We'll see. I was antagonizing Steven Kephart about this on another thread but he hasn't gotten back yet.
Alpine Guy wrote:
I was once in your position and now im here with only 2 more years of school left and I'll be making the amps people on this site will be frying.
Really? In two more years I'll be the lawyer you hire when your amp catches fire and kills someone.  ------------- "I'm finished!" - Daniel Plainview
Posted By: astro88
Date Posted: November 12, 2006 at 10:51 AM
One last question. Could i be ruining my amp by not supplying proper current to it or is it just safely limited output wattage determened by the power im giving it?
Posted By: astro88
Date Posted: November 12, 2006 at 3:13 PM
The reason i ask is becuse the output dosent sound good,is this only due to the input voltage lacking
I rearranged my system some today t i went to a lower wattage set up until i can upgrade the electrical system.
I had a punch 45 HD laying around and i bridged it to 2 ohms (my L7 12) in a ported to 28hz box and its way louder than the 1200.1 pushing the two re's, now im afraid i may have damaged the amp?
The re's are in a sealed enclosure 0.77 cft per sub. Even when i wired them at 4 ohms the output was nowere near what my low watt set up is now? im confused......
I much appreciate all of the input in this post as ive learned some helpfull knowledge!
When i do upgrade it will be with a ho alternater paired with a yellowtop.
Posted By: sedate
Date Posted: November 12, 2006 at 4:35 PM
astro88 wrote:
The reason i ask is becuse the output dosent sound good,is this only due to the input voltage lacking
I rearranged my system some today t i went to a lower wattage set up until i can upgrade the electrical system. |
Amplifiers today generally have circuitry that shut them off when the input voltage drops below ~10v or so.. You ought not hear distorted output, rather, output for a few seconds, then nothing, then a few more seconds of output. I'd be suprised if you damaged the amp itself.. you'd need a bad ground or shorting wires or something like that to damage the amp. astro88 wrote:
I had a punch 45 HD laying around and i bridged it to 2 ohms (my L7 12) in a ported to 28hz box and its way louder than the 1200.1 pushing the two re's, now im afraid i may have damaged the amp? The re's are in a sealed enclosure 0.77 cft per sub. Even when i wired them at 4 ohms the output was nowere near what my low watt set up is now? im confused......
Not really suprised here... you amplifier really doesn't have all that much to do with total output.. you're re's are in REALLY small enclosures, sealed, and they're only 10's. The cone area on that L7 has got to be almost as much as the 2x10's..those square subs really move more air than comparative round subs. Nevermind the fact that the box is ported... a huge increase in volume and output right there alone. Always remember astro, your enclosure has FAR MORE to do with output/sq than ANY OTHER factor in your system... save possibly the shape/size of the vehicle itself. Air movement is what produces sound, and the shape/design of your box goes the farthest to influence this. Anyway, point being, if you didnt' kill your alt or battery with all your tribulations, I don't see how you could've hurt your amp. I'd get/build a different box for those 10's anyway.. maybe ~2cft, tuned to 30 - 35hz.... but as the two different sub configurations stand, the L7 would require considerably less power to get considerably lounder. ------------- "I'm finished!" - Daniel Plainview
Posted By: Mad Scientists
Date Posted: November 12, 2006 at 6:11 PM
Some thoughts while reading this thread.. Alternator rating is *max* output.. which typically doesn't happen at idle. Most alternators also can't output max rated output for long without overheating and failing.. Starting current for a car is generally 100+ amps or more.. the rule of thumb I use is 1 amp for each cu in of engine displacement. A 3.4 liter engine would draw approximately 150-200 amps. When system voltage is 12.8v and higher, no current is flowing out of the battery. The alternator is supplying all the power required by the vehicle. The battery only supplies current when system voltage drops to approximately 12.4v.. this means that from 14v down to 12.4v the alternator is doing all the work. Once 12.4v is attained, the battery starts draining. While a larger battery bank will help maintain higher voltage during times when the alternator isn't capable of supply the needed power, the larger battery bank does place more of a load on the alternator when recharging. Some alternator manufacturers recommend sizing the battery bank to no more than 2x the max alternator output. Example would be a 100a alternator should be hooked to a battery bank with a capacity no greater than 200 Ah. (in contrast, whereas a battery will not provide power until system voltage drops to 12.4v or so, a capacitor supplies power as soon as the voltage drops to less than what the capacitor is charged to) Battery voltage and alternator voltage are the same.. less any voltage drop in the wiring. While it was an acceptable method to check an alternator/generator in older vehicles to disconnect the battery with the engine running (if the engine continued to run then the alternator is good) on todays vehicles there stands a real good chance of smoking electronics due to the possibility of voltage spikes (due to the loss of the damping effect of the battery) to address astro88's situation directly, if the alternator is working properly and the wiring is sound, then you are probably using more power then the alternator is capable of providing. You are correct that by installing a larger battery bank you load the alternator more; your best solution would be to either reduce the power draw or increase the power output of the charging system. However, if by your comment that the lights dim with the blinker on (assuming the stereo is off) then this indicates a possible problem elsewhere.. voltage drop measurements would be critical at this point to establish that the wiring is in good condition. Any questions?.. Jim
Posted By: astro88
Date Posted: November 12, 2006 at 7:14 PM
Mad Scientists wrote:
to address astro88's situation directly, if the alternator is working properly and the wiring is sound, then you are probably using more power then the alternator is capable of providing. You are correct that by installing a larger battery bank you load the alternator more; your best solution would be to either reduce the power draw or increase the power output of the charging system. However, if by your comment that the lights dim with the blinker on (assuming the stereo is off) then this indicates a possible problem elsewhere.. voltage drop measurements would be critical at this point to establish that the wiring is in good condition.
The lights dim still with the punch 45hd but hardly noticable at this point,im still amazed at the power this little gems putting out lol. As for dimming with blinkers on,yes still doing it,stereo off. I havent yet checked the resistance on the ground path, i will as soon as i get a chance(seems this stupid car is all i live for these days. (sedate) As for the sealed re's compared to the l7 ported,ya i know about l7s lol thats why i bought it. I ve came up with a ported box plan for my re's from the winld whatever program 1.25 cf @ 34 hz as re suggests,hope that helps output,kinda took a chance buying re(never even heard of em b4.
Posted By: Alpine Guy
Date Posted: November 12, 2006 at 10:28 PM
sedate wrote:
Alpine Guy wrote:
With my mechman alternator I could sit at a stop light with the bass cranked on a bass cd and not get light dimming. (3000WRMS System)
REALLLY??
Sooo.. assuming your amplifiers are perfect machines and output 100% of the power they get (which they don't), you are using 200 - 240 amps of current. So on a 180amp alt (your sig) you using your... wait what... this can't be...
your battery to filter the extra current draw?
Is that what is happening in your car?! I can't believe it! So I am, indeed, correct in everything I've told our poster?!
I thought so.
At the time I had that stereo I was running a 225 amp Mechman alternator with a smaller pulley as recommended by them for my motor, which is why it ran so well, just wanted to add that However I do have to confess I didn't thoroughly real all the posts to get your complete understanding of the plan at hand. ------------- 2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
Posted By: Mad Scientists
Date Posted: November 13, 2006 at 11:27 AM
If your lights are dimming with the blinkers on and stereo off, then it sounds like you might have other problems.. Don't bother with the resistance measurements; measure voltage drops instead. resistance measurements are pretty meaningless.. to demonstrate this, tell me if a 0.5 ohm resistance is acceptable.. then apply ohm's law to that using 200 amps (starter current).. what's the voltage drop? Jim
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