battery vs 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=101949
Printed Date: May 28, 2024 at 11:30 PM
Topic: battery vs alternator
Posted By: frizkysquirrel
Subject: battery vs alternator
Date Posted: February 06, 2008 at 2:41 PM
i have a 1997 ford escort with a 75 amp alternator.
my amplifier will be drawing a maximum of 80 amps.
i went to get a quote on a high output alternator.
instead of a quote the head person at the shop said my best bet would be to put in another battery in the trunk which would be grounded in the trunk and the positive of the battery ran to the positive of my initial battery.
i seem to think this would make it worse off on my alternator.
in my understanding putting in another battery would increase the draw from the alternator because it would now have to charge two batteries.
my question would be:
Would putting in the second battery be the best choice or should i go with the 170 amp high output alternator?
Replies:
Posted By: KPierson
Date Posted: February 06, 2008 at 3:17 PM
High amp alternator. As you already know batteries only add a load to the alternator. The proble you are going to have is that you arn't generating enough power, adding a second storage device won't help.
-------------
Kevin Pierson
Posted By: greenbroncoguy
Date Posted: February 06, 2008 at 3:24 PM
^^^ Yep, I would go w/ the HO alt before I put in another battery. But I would also upgrade your battery before I added another one... -Matt
Posted By: bellsracer
Date Posted: February 06, 2008 at 3:59 PM
I say go both. Start with the alternator and then add your second battery using a battery isolator. This will take the loading issues with your new alternator and still give you that extra energy when you drain your primary battery >.< Personally though, I would go HO alternator and a strong Capacitor. A 2nd car battery just delays the inevitable drain on the charging electrical system. The cap will assist when needed during the heavy hits without being a pain to your alternator. the Cap will also give a better discharge (1 farad will give 80+ amps of instant power for 1 second) and not be hurt by the drain. ------------- Never send your ducks to eagle school.
The difference between ordinary and extraordinary is that little extra.
The 3Ls of life: Learn from the Past, Live for the Present, Look to the Future.
Posted By: greenbroncoguy
Date Posted: February 06, 2008 at 4:12 PM
First of all, when you say, " My amp will be drawing a maximum of 80amps", I'm guessing that it has 80amps worth of fusing built in, correct? If this is true, then that amp is not going to draw anywhere NEAR 80 amps hardly ever, and if this is all the equipment you have, then you may not need anything at all. But you certainly do NOT need 2 batteries when the only addition to your system is a <800w amp... You may want to get the alternator if you are going to be using the amp for sub duty and playing loud, you may also want to get the upgraded battery as well if you plan on playing the system with the engine not running. But you REALLY don't want to get two batteries, of any type, without upgrading the alternator. -Matt
Posted By: sedate
Date Posted: February 06, 2008 at 4:20 PM
80 amps? You do not need an HO alt or a second battery. Jeeze car audio clerks are stupid. Okay - Big 3 - https://www.the12volt.com/installbay/forum_posts.asp~TID~73496~PN~1 and a deep cycle: https://www.autobarn.net/opbatdeepcyc.html Done. ------------- "I'm finished!" - Daniel Plainview
Posted By: frizkysquirrel
Date Posted: February 06, 2008 at 11:02 PM
i already upgraded the big three.
and yes it has an 80 amp fuse.
Its a hifonics amp the brutus bxi1206.
my headlights still dim on heavy bass hits with my system with my 300 watt rms amp right now even after i upgraded the big three with 2 gauge.
i need to get a deep cycle battery, but from everyone's input and my reasoning it seems i will need a ho alt too.
thank you for all of the input.
Any more sugestions on what will truly be enough to adequately power my system without hurting any of my cars electrical would be greatly appreciated.
Posted By: sedate
Date Posted: February 06, 2008 at 11:09 PM
You'll need the Deep Cycle anyway - get it first and see if it solves your problems - I'm tellin ya man - I'm savin ya money..
-------------
"I'm finished!" - Daniel Plainview
Posted By: frizkysquirrel
Date Posted: February 06, 2008 at 11:15 PM
yea, ill get a deep cycle first. but ill probably get the alt anyways.
i may get a bigger system some time anyways so ill leave myself the room.
Posted By: sedate
Date Posted: February 07, 2008 at 12:02 AM
See - with a proper deep cycle - I think you'll find the dimming lights and all residual power problems will be taken care of - I can't tell you how much more power an Optima Yellow is over whatever a stock Escort battery is. Anyway - please post back and let us know what happens - I'd like to know. Out of curiousity, where were you planning on getting your HO alternator? ------------- "I'm finished!" - Daniel Plainview
Posted By: greenbroncoguy
Date Posted: February 07, 2008 at 9:17 AM
frizkysquirrel wrote:
yea, ill get a deep cycle first. but ill probably get the alt anyways.
i may get a bigger system some time anyways so ill leave myself the room.
Actually, if you don't plan on repeatedly discharging the bottery totally(read: playing the system with the car off until the battery is dead alot), then a Red Top regular starting battery is probably going to help you dimming situation out more then a deep cycle. It will have higher cold cranking/cranking amperage ratings, so it will deliver more juice to help solve your dimming issue. The only benifit of using the deep cycle is as I ststed, it will hold up better to repeated full discharges/charges... -Matt
Posted By: haemphyst
Date Posted: February 07, 2008 at 10:24 AM
greenbroncoguy wrote:
frizkysquirrel wrote:
yea, ill get a deep cycle first. but ill probably get the alt anyways.
i may get a bigger system some time anyways so ill leave myself the room.
Actually, if you don't plan on repeatedly discharging the bottery totally(read: playing the system with the car off until the battery is dead alot), then a Red Top regular starting battery is probably going to help you dimming situation out more then a deep cycle. It will have higher cold cranking/cranking amperage ratings, so it will deliver more juice to help solve your dimming issue.
The only benifit of using the deep cycle is as I ststed, it will hold up better to repeated full discharges/charges...
-Matt
X500!!!! Red top is better, and here's a thread from the forum, that explains why... The answer to your question is about halfway down the first page.
Trust me, the red-top is FAR better for car audio applications! ------------- It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: n2audio
Date Posted: February 07, 2008 at 10:38 AM
bellsracer wrote:
the Cap will also give a better discharge (1 farad will give 80+ amps of instant power for 1 second)
I would REALLY like to see the math that leads you to that conclusion.
Posted By: sedate
Date Posted: February 07, 2008 at 11:23 AM
heamph's other post wrote:
On to the differences between standard (red-top) and deep cycle (yellow-top) batteries. NOTHING. They are the same, save the THICKNESS of the plates they are built with - deep cycle being up to 25 percent thicker. Because the current a battery can produce comes from a chemical reaction, the number of plates (or total surface area of the plates - 25% thicker means 25% fewer plates, means 25% less peak current...) will DIRECTLY affect the amount of peak current it can produce, because you have fewer plates, right? If you have a battery case of X volume, and you place battery plates within it, it will make X current, right? If you have the same battery case, but you place thicker plates in it, you will be able to get LESS peak current, right? Now, red and yellow top batteries are the same size case... the deep cycle version, (yellow top) has FEWER plates, right? Which one is better for CURRENT? The red top, right? What does a car amp need to produce power? Current, that's right. Now which one will you choose? Me? I'm saving the cash, and getting a better battery for my application, and gonna buy the red top.
heamph :::shakes head::: if we were talking fancy class d amps, xover points, quality drivers - I'd defer. I know you can install a better system. But your devotion to these Red Tops is real, real misplaced. You repeatedly telling people these are better for car audio is simply poor advice that is going to cost people money and frusteration- it belies Optima itself, and clearly you've never used these batteries side by side (if you did you wouldn't continue telling people this) - and your 'CURRENT CURRENT CURRENT' mantra is simply wrong. heamph wrote:
Trust me, the red-top is FAR better for car audio applications!
Your basic argument, which you obfuscate behind an explanation of plates or whatever, has remained the same ever since we first argued over these batteries, and is flawed at its basic premise: https://www.the12volt.com/installbay/forum_posts.asp~TID~67715~KW~sedate~PN~0~TPN~1 (2nd, 3rd pages) My system needs a peak of 200 amps - so I need the battery that can provide a peak of 600 amps because a peak of 500 amps isn't enough? Exactly. It doesn't make any sense. Both of these batteries would - momentarily - power an electric chair. EITHER battery will supply SEVERAL TIMES the CURRENT that the system will require - a battery that can WITHSTAND THESE CURRENT DEMANDS is what is required. Look frizkysquirrel, read heamphs own posts on the subject and he admits the Yellow is Deeper cycling battery - what matters here is NOT current - either battery can supply far more than your system could ever require - what matters is the ability to withstand the current demands that are being foisted upon the electrical system - the Red Top will NOT do this over the long term when mated to a sufficiently powerful system. The Yellow will. ------------- "I'm finished!" - Daniel Plainview
Posted By: haemphyst
Date Posted: February 07, 2008 at 12:26 PM
I also know that the red-tops are FASTER than the yellow... Another benefit to thinner plates... Every electrochemical device will have a slew rate, and the speed of the current delivery is also an important factor.
I have indeed used both red and yellow tops in my systems, and I can assure you that I have never had any issues with the red-top. Yes, to answer your next question, I HAVE, (and do quite regularly) engaged in extended "parking lot listening sessions", and even with a red-top battery, I have never been left stranded, NOR have I ever had to replace one, and I mean that VERY literally - I've never had one "die". I put one in my '86 Civic, (that one lasted over 5 years) and I now have one in my '01 Civic, and it is almost 6 years old! In every system I have ever installed in ANY of my cars, I have never seen even ONE compelling argument to insist that the yellow-top is a better option. Still, I prefer the red-top, BECAUSE it is a better battery, and I will continue to assert that - it's specifications and construction tell me it is so. Going back to your argument, if they BOTH perform identically, and they BOTH are "deep-cycle" (of sorts) due simply to their construction, why not spend LESS money on an equivalent battery, (with, still in my views, better specifications) and recommend the red-top??
-------------
It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: KPierson
Date Posted: February 07, 2008 at 2:22 PM
I had to replace the red top in my G35 about a year after it was installed because it wouldn't hold a charge. And I have an OEM stereo. My problem is the car sits a lot, and the red top simply couldn't last in that situation (driving a the one weekend a month). I replaced it with a red top, because they honored the warranty, but if I had it to do over I would have bought a yellow top. ------------- Kevin Pierson
Posted By: greenbroncoguy
Date Posted: February 07, 2008 at 3:02 PM
sedate wrote:
heamph's other post wrote:
On to the differences between standard (red-top) and deep cycle (yellow-top) batteries. NOTHING. They are the same, save the THICKNESS of the plates they are built with - deep cycle being up to 25 percent thicker. Because the current a battery can produce comes from a chemical reaction, the number of plates (or total surface area of the plates - 25% thicker means 25% fewer plates, means 25% less peak current...) will DIRECTLY affect the amount of peak current it can produce, because you have fewer plates, right? If you have a battery case of X volume, and you place battery plates within it, it will make X current, right? If you have the same battery case, but you place thicker plates in it, you will be able to get LESS peak current, right? Now, red and yellow top batteries are the same size case... the deep cycle version, (yellow top) has FEWER plates, right? Which one is better for CURRENT? The red top, right? What does a car amp need to produce power? Current, that's right. Now which one will you choose? Me? I'm saving the cash, and getting a better battery for my application, and gonna buy the red top.
heamph :::shakes head::: if we were talking fancy class d amps, xover points, quality drivers - I'd defer. I know you can install a better system. But your devotion to these Red Tops is real, real misplaced. You repeatedly telling people these are better for car audio is simply poor advice that is going to cost people money and frusteration- it belies Optima itself, and clearly you've never used these batteries side by side (if you did you wouldn't continue telling people this) - and your 'CURRENT CURRENT CURRENT' mantra is simply wrong. heamph wrote:
Trust me, the red-top is FAR better for car audio applications!
Your basic argument, which you obfuscate behind an explanation of plates or whatever, has remained the same ever since we first argued over these batteries, and is flawed at its basic premise: https://www.the12volt.com/installbay/forum_posts.asp~TID~67715~KW~sedate~PN~0~TPN~1 (2nd, 3rd pages) My system needs a peak of 200 amps - so I need the battery that can provide a peak of 600 amps because a peak of 500 amps isn't enough? Exactly. It doesn't make any sense. Both of these batteries would - momentarily - power an electric chair. EITHER battery will supply SEVERAL TIMES the CURRENT that the system will require - a battery that can WITHSTAND THESE CURRENT DEMANDS is what is required. Look frizkysquirrel, read heamphs own posts on the subject and he admits the Yellow is Deeper cycling battery - what matters here is NOT current - either battery can supply far more than your system could ever require - what matters is the ability to withstand the current demands that are being foisted upon the electrical system - the Red Top will NOT do this over the long term when mated to a sufficiently powerful system. The Yellow will.
How did I know this was coming? How is referring people to the Red Top batteries going to cost them MORE money when they cheaper than the Yellow Top's, and in my experience last LONGER as well? I'm guessing that you're basing your argument on the premise that, being that the Red Tops are less reliable and will have to be replaced more often, they will have to spend more money in the long run - which I can dispell right here and now because i have owned(and still do) BOTH types of batteries. How many Yellow Tops have I had fail on me? 2. Now I will admitt that 1 of the 2 as been through 2 auto accidents, and has a 6" slit in the side of it (and still worked for a year or so after the last wreck) - BUT, it only lased 3 years, and my other Yellow Top is on it's way out, which I have had for about the same amount of time... I have had the same Red Top for nearly 5 years, it has been completely discharged several times, and has never refused to start my 12.5:1 big block in my Bronco by ITSELF. Now, I had 2 of the Yellow Tops origionally in my Bronco because I used to think, like you Sedate, that the Yellows were better, and if I had 2, then I could also have more cranking amps than just one Red, right? Well, 2 of them did work better than 1 red, but then they started going bad on me and now all I have currently is one red top. I also have one red top in my Maxima, and it starts my car better than a yellow top, and it's just a fairly stock engine on the inside... Following your logic that "if your system will need a peak of 200 amps, and the battery can supply a peak of 600 amps", then that battery should perform exactly the same in that same car as one that could supply 900 amps, correct? And this would apply as well to starting the car as well, correct - being that a starter only draws about 200-300 amps AT MOST to start the car? Well, I can tell you for a fact, that if you put a Yellow Top battery in my Bronco, which I have pulls ~200a on a cold start up it will crank slower than a Red Top battery if both batteries have a resing voltage that is exactly the same. -Matt
Posted By: sedate
Date Posted: February 07, 2008 at 3:10 PM
KP]
I had to replace the red top in my G35 about a year after it was installed because it wouldn't hold a charge. And I have an OEM stereo. My problem is the car sits a lot, and the red top simply couldn't last in that situation (driving a the one weekend a month). I replaced it with a red top, because they honored the warranty, but if I had it to do over I would have bought a yellow top.
Yup! These other guys - it must be difficult - taking authority as truth rather than truth as authority . . . ------------- "I'm finished!" - Daniel Plainview
Posted By: haemphyst
Date Posted: February 07, 2008 at 3:29 PM
KPierson wrote:
I had to replace the red top in my G35 about a year after it was installed because it wouldn't hold a charge. And I have an OEM stereo. My problem is the car sits a lot, and the red top simply couldn't last in that situation (driving a the one weekend a month).
I replaced it with a red top, because they honored the warranty, but if I had it to do over I would have bought a yellow top.
While the POINT may be true, an you may have VERY WELL HAD to replace your red-top, HOW CAN YOU SAY WITH 100% CERTAINTY that the yellow-top would NOT have done the same thing in the same situation? You cannot.
Yours, sadly, is an invalid argument... ANY battery will self discharge, and will eventually fail due to that self discharge. You cannot say that it was the battery's fault, in this case. Any battery can and will eventually fail due to improper or incomplete charging cycles, even the "blessed" yellow-top!
I, right now, have a second red-top, sitting on the floor of my garage, and it has set there for about 9 months, actually. My neighbor needed a jump-start, and I picked it up, and walked it over to him. 2 minutes, and a pair of jumper cables later, he was running. Strangly enough, the battery in my motorcycle had gone dead that morning, as well, so I grabbed the SAME battery, and after sitting on the ground (which everybody says will hasten self-discharge) for 9 months, AND jump starting a car, I was able to even still jump my motorcycle! It's never been attached to a charger!
I firmly believe that Optima is using "deep-cycle" or "yellow-top" as a marketing gimmick. I have never been shown that there is any benefit to that particular battery. ------------- It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: KPierson
Date Posted: February 07, 2008 at 4:30 PM
haemphyst wrote:
While the POINT may be true, an you may have VERY WELL HAD to replace your red-top, HOW CAN YOU SAY WITH 100% CERTAINTY that the yellow-top would NOT have done the same thing in the same situation? You cannot.
Yours, sadly, is an invalid argument... ANY battery will self discharge, and will eventually fail due to that self discharge. You cannot say that it was the battery's fault, in this case. Any battery can and will eventually fail due to improper or incomplete charging cycles, even the "blessed" yellow-top!
The point of my story was to show that A. any battery can fail and that B. the Red Tops are not perfect. I firmly believe that I deepcycled by Red top by letting it sit. As we all know, after deep cycling a battery it will never hold a full charge. That was the exact situation I had - a battery that worked, but would die in 2-3 days of non use. On the same token, back in the day when I had my Cavalier I had a yellow top in it. I rarely drove that car, but once I recharged the yellow top it was fine. I had that yellow top for 4+ years with no issues at all, and quite a few complete discharges. I can safely say you can completely discharge a yellow top with no loss in storage capacity. I can also safely say, from my personal experiance, you can NOT discharge a red top and expect it to operate anywhere near 100% of its original ability. I'm by no means a battery expert and I'm speaking solely on my personal experiance with each battery. Summary : Yellow top installed in car with 1000 watt RMS system for 4+ years and several battery discharges - perfect Red top installed in car with stock stereo for 1 year and 2-3 discharges - time for new battery. The last thing I will add is someone along the way told me that Optima changed their design and that their new yellow tops weren't as robust as their old yellow tops. If this is in fact true, which I don't know if it is or isn't, then that may explain some things. ------------- Kevin Pierson
Posted By: sedate
Date Posted: February 07, 2008 at 11:17 PM
Ahh - sadly - I think we've reached an impasse. Clearly - none of us can 'win' the point. Anyway - I think I'm our only resident law student, so I do want to point out that ALL of our 'evidence' entered into this thread falls into the in-admissible category of "hearsay" - as in unsubstantiated, unscientific obseravation that is nothing so much as a single person saying "I saw this this and this.." in a second hand manner, without witnesses or corroborating evidence. I think heamph, myself, bronco, and KP are all guilty here - we clearly can't work this out saying "I saw X, Y, and Z from my Optima..." Anywho - I really, really wanna get to the bottom of this. I think the12volt should at least have some consensus among our more active members.. to many posts deal with this issue and I clearly can't run behind heamph - or he behind me - arguing this stupid point. I'm gonna find definitive answers we can all agree on. ------------- "I'm finished!" - Daniel Plainview
Posted By: greenbroncoguy
Date Posted: February 08, 2008 at 1:23 AM
sedate wrote:
Ahh - sadly - I think we've reached an impasse. Clearly - none of us can 'win' the point. Anyway - I think I'm our only resident law student, so I do want to point out that ALL of our 'evidence' entered into this thread falls into the in-admissible category of "hearsay" - as in unsubstantiated, unscientific obseravation that is nothing so much as a single person saying "I saw this this and this.." in a second hand manner, without witnesses or corroborating evidence. I think heamph, myself, bronco, and KP are all guilty here - we clearly can't work this out saying "I saw X, Y, and Z from my Optima..." Anywho - I really, really wanna get to the bottom of this. I think the12volt should at least have some consensus among our more active members.. to many posts deal with this issue and I clearly can't run behind heamph - or he behind me - arguing this stupid point. I'm gonna find definitive answers we can all agree on.
You can practice all the law you want, 85% of what you just posted is blatantly asinine and has nothing to do with the thread. 1/3 of the posts on this entire site are opinion, usually based mostly on personal experience with a certain product. "...in-admissible category of "hearsay" - as in unsubstantiated, unscientific obseravation that is nothing so much as a single person saying "I saw this this and this.." in a second hand manner, without witnesses or corroborating evidence." - wth? Who's judging this whole thread - where's the jury? I don't remember who the hell my client is even ? If I'd have know this was a court of law, I'd certainly have come more prepared; oh, wait, I'm only 21 years old have never taken a cousre in law - but I think I've hung fairly well with someone who's supposedly our leading law "expert"... Look, all I'm saying is that most of what people advise is going to step from personal experience, unless it is a post linked or quoted from some sort of research. There's nothing wrong with personal opinion, as most people coming to forums like this are in fact asking for it... -Matt
Posted By: frizkysquirrel
Date Posted: February 08, 2008 at 1:57 AM
well.
i guess ill just relax untill my alternator dies or sumthing.
i cant figure out much from this thread, all i really want to know is would getting a ho alternator be a good idea? or would i not need it running around 800 rms on a stock 75 amp alt?
Posted By: sedate
Date Posted: February 08, 2008 at 1:57 AM
greenbronco wrote:
I think I've hung fairly well with someone who's supposedly our leading law "expert"...
Wow. And here I was *trying* to be pragmatic. Um. No - you haven't really hung with me - we haven't really engaged over the course of this thread so I think you just like to follow my posts around and be disagreeable.  greenbronco wrote:
where's the jury? I don't remember who the hell my client is even
Jury? I dunno - agreement - or at least some general consensus - on a quantifiable question? Jeeze dude. greenbronco wrote:
unless it is a post linked or quoted from some sort of research
Actually - and if you can't see this I certainly cannot hope to get the point across to you - this is a sort of neato argument because it *is* quantifiable. ------------- "I'm finished!" - Daniel Plainview
Posted By: sedate
Date Posted: February 08, 2008 at 2:03 AM
fritzkysquirrel wrote:
i cant figure out much from this thread
Yikes! Sorry dude.
Anywho - um - try a better battery first. Take your pick which one from the thread - you really aren't asking that much - 80 amps is a pretty tame load all things considered - Red, Yellow - Blue - whatever. So where were you planning on getting an HO alt from anyway? This is sort of the critical factor in whether or not you should - uhh - purchase one. ------------- "I'm finished!" - Daniel Plainview
Posted By: jmelton86
Date Posted: February 08, 2008 at 2:56 AM
Hopefully all the pointless arguing is over with... I'll try to sum this up for you. If you'll be using a lot of electrical components (A/C, heater, etc...) in the car while the system is turned up, then i'd recommend the HO alternator (the largest reputable name you can afford), then a nice battery or two (depends on if you'll be listening with the car off for long periods of time). Otherwise, if you're smart about it, the Big3 and a nice battery will be good for you. I've got about 90amps worth of system fusing AND two Yellowtops (in parallel, no isolator or the such) on my factory 105a alternator (Big3 in 4g of course...) with NO headlight dimming or voltage drop issues. Gosh, I think people just like to argue... Oh, and the word is truthiness. It means to state your opinion as facts without any evidence. ------------- 2013 Kia Rio -90a alternator
DDX470HD GTO14001 GTO1014D (x3)
Big3 in 1/0G
1/0G to GTO14001
Posted By: stevdart
Date Posted: February 08, 2008 at 7:01 AM
friskysquirrel wrote:
Any more sugestions on what will truly be enough to adequately power my system without hurting any of my cars electrical would be greatly appreciated.
friskysquirrel, for a 10 y o Escort and for what you've described as your system, you could probably just buy a fresh upgraded battery. A black top...like the original... ]i alr wrote:
ady upgraded the big three.
...and it depends on whether a fresh new battery was a part of this upgrade. Also be sure to test, to be sure, that resistance is minimal from the amp's ground connection to the source. ------------- 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: n2audio
Date Posted: February 08, 2008 at 8:38 AM
n2audio wrote:
bellsracer wrote:
the Cap will also give a better discharge (1 farad will give 80+ amps of instant power for 1 second)
I would REALLY like to see the math that leads you to that conclusion.
All this battery BS and nobody's answered the question worth answering -- according to my math it's closer to 3A/sec, and that's not accounting for ESR OR ESL. BTW - if it's going to be deep cycled, yellow, if not red -- why does it have to be so complicated?
Posted By: n2audio
Date Posted: February 08, 2008 at 8:43 AM
frizkysquirrel wrote:
i cant figure out much from this thread, all i really want to know is would getting a ho alternator be a good idea? or would i not need it running around 800 rms on a stock 75 amp alt?
It will depend on the car's stock electrical demand and your listening habits. I used to drive an '88 turbo Tbird. Stock alt was 75A and it was widely recognized that the alt was undersized w/o aftermarket electronics -- however, being the hard headed person that I am I proceeded to build a ~1000w rms sound system. At idle it struggled - especially when the electric radiator fan(s) were running. However, during normal driving it maintained 13v+, and it ran like that for about 2 yrs before the alt finally died. It had 226k on it at that point. I replaced it with a 110A and it was more than sufficient.
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