Heres the story: I've got a stock 100 amp alternator in my Tahoe as it is. I've also got an old 1 farad cap and a red top optima, but my lights will still dim pretty good. :angry: I was thinking I should buy this remanufactured 140 Amp alternator. Is this a good idea? I'm pushing around 1900 watts, and I know Ohms law is Watts/Voltage= Amps So 1900/12.8=148 Amps. So here's a shitload of questions: -Would a 140 Amp alternator be sufficient for my set up? -If not, what are some brands I should look into? -Any suggestions of other alternators that are under (or around)$200? -With decent mechanical/electrical skills, is it easy to install? -Would a new capacitator solve my problem? -Or should I just say "fuck it" and give away my system? :lol: Thanks a lot fellas.
Is that optima in addition or your single battery? If in addition, how is it wired up? How's your whole system wired, including under the hood? An alt is easy to swap out...by you asking that, I assume you haven't done the "big 3" upgrade...maybe look into doing that first? There's a thread over on CAF about caps claiming they're pretty useless. I wouldn't be surprised if this were true. I have a .75F cap and it doesn't seem to help at all. I don't think you can do a straight conversion like that, especially since your amps are not 100% efficient. Now that I've said that, yes, just give your system to me and I'll dispose of it for you
Its my starter battery. I've upgraded the "big 3", with 4 gauge wire... Need any other info about my setup? Yea, I know what you mean about the straight conversion. I was just trying to get an idea of what I need, and I know I definately need a better alternator...
Here's that thread on CAF: http://www.caraudioforum.com/vbb3/showthre...light=capacitor See what others think, but a new alt may be the way to go...
Probably the best and cheapest route would be to purchase a second battery and an isolator for it. Larger alternators usually dont put out their rated amperage at idle, most of the time the origonal alt puts out more at idle than the bigger alt. Seth has explained dual battery setups detail before but I dont think that information is around anymore. Here is what I picked up on it. Having two batterys wired in parallel halfs the resistance of the batterys so the alternater can work more efficiently. Its just like bridging two 4 ohm SVC subs to get 2 ohms, resulting in more power from an amp. So putting a second battery in does not require a larger alternator. A second battery should solve or at least lessen the dimming of the lights. Then there is Geo with his "dimming lights arent nessesarily a problem" explaination. I dont really remember what he was saying.
what geo means by "dimming is not a problem" is that "it is not a problem" more of an annoyance. The Dimming is Caused by a Voltage Drop in the Eletrical System.. Say from 14V down to the Batterys 12v operating voltage when you Knock 2volts off the Headlight Ciruit you get dimming.. that does not Mean your cars going to Blow up or anything though
dual batteries might not help that much... im running about 1800 watts on my 96 gmc truck and i put in dual batteries...helped out a little but not like i wanted it to everytime im at a stop light the voltage still drops to 12volts i dont know too much about aftermarket alternators, but i know if you go with Irragi or Ohio itll probably cost you over $350 new...might try ebay?? id personally go for the bigger alt., $200 isnt a bad price...but as someone mentioned...check what its rated at 140 amps at you want to look for an alt. that puts out a lot of volts at 700 rpm's...that alt. might claim 140...but its 140 at 5k rpms... just beware -Cody
Music is dynamic. You will only hit 1900w out of your amps when the following all happen at exactly the same time: 1) you have your volume all the way up 2) you reach a portion of the recording that actually reaches the -0dB peak recording level It certainly doesn't happen continuously... rendering your ohms law calculation useless (sorry about that). In fact, an amp capable of drawing 150a of current, in actual use, on real music, will actually draw closer to an average of 25a-30a worth of current, even though it may occasionally reach peak current draws near its 150a max. Those peaks aren't an issue either, as your electrical system has built in means of contending with those... When a demand comes along that's more than the alternator can currently handle, system voltage simply drops... Down from the 14.4v unburdended voltage of the alternator, to the 12v level of the battery, where the alternator and battery work together to provide the excess current, until that demand stops (and with music, that's generally less than a second)... at which point the system voltage again rises to 14.4v and your battery charges the little current that it lost, in about the same amount of time. It's nothing to worry about, it's certainly not a problem, and your only symptom is your lights dimming - and that's simply because light bulbs are brighter on 14.4v than they are on 12v. ...if anything, you might think about adding a capacitor, to help reduce the drama of the light dimming, act as a 'shock absorber' for those transients when the battery is called into play. It can help. Besides that - the big 3 are cheap upgrades. Of course, make sure your main power cables are big enough, if not overkill sized. Most likely, you don't need to do anything... not adding a second battery, not upgrading your alternator, nothing. Make sense?
