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New member Username: KrankitupPost Number: 1 Registered: Nov-04 | Ok, I'm sure this has been beat to death. But I recently rewired my amp so it's bridged and now my lights dim. I installed a .5 cap but that didn't help. I'm planning on installing a 120 amp alternator because that is the largest I can find. I currently have a 90 amp alternator. Do you think this extra 30 amps will help? My amp when bridged is getting 460 RMS. Thanks in advance. |
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Silver Member Username: CarguyPost Number: 414 Registered: Nov-04 | Hey Casey, what is the fuse sizes on your amp? That should tell you how much power it's going to demand. If you do a simple math, 460W rms will suck up almost 40A. 90A alternator should be plenty enough to power your amp. However, if you have other power hungry devices besides the amp, then it'll eat away at the reserve power. FYI, your .5 cap is undersized. It should be 1000W peak per 1F. Try getting a 1F - 1.5F cap first. It just might end your light flickering problem. If you can get HO alternators greater than 120A. Try 4alterstart.com. They have 170 - 200A. And if you need more, they can custom make it. |
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New member Username: KrankitupPost Number: 2 Registered: Nov-04 | The amp peaks at 800 watts so I figure my lights dim is when it's sucking it's peak power. 800 watts is almost about 65 amps. I'm using more than 35 amps on other stuff I'm sure. A/C, power steering, heated seats, blah blah blah. I picked up the 120 tonight, so I hope that does the trick. I'd prefer not to have a custom one so I don't have to use any special brackets or anything. Thanks for the help. |
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Silver Member Username: CarguyPost Number: 432 Registered: Nov-04 | 120A will certainly help. Don't forget to get a bigger capacitor. |
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Azzhole Unregistered guest | Skip the cap, and do a big 3 if youre still dimming. Caps are for stiffening voltage rails, not curing electrical shortages. Isaac needs to read. |
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Silver Member Username: CarguyPost Number: 440 Registered: Nov-04 | Guy, I read it many times. I was suggesting that he should get a capacitor for tight smooth bass. It will never replace the HO alternator, that everyone agrees, however capacitors serve a different purpose. |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 5935 Registered: Dec-03 | the alternator will help. you'll want to run the same size power cable from alt to batt, and batt to ground, and batt to amps to insure good current flow. A capacitor will smooth spikes in demand, but it won't stiffen voltage rails. Not for more than a few seconds anyway, and if your lights are dimming, your cap won't recharge anyway due to the already severe lack of current. Just leave the half farad cap you have now in the car. Don't worry about increasing it for a 460W amp. |
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New member Username: KrankitupPost Number: 3 Registered: Nov-04 | Well, my lights still dim even with the bigger alternator. Which pisses me off because now I've wasted $300. What else could it be? All my wires appear to be the same size. I'm not sure what gauge, but they're not tiny. So now I have a 120A alternator, .5 cap (which I guess is too small) and an amp that's only taking 460 watts RMS. I know there are people running larger systems than that without trouble. |
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Silver Member Username: CarguyPost Number: 478 Registered: Nov-04 | Hey Casey, just when does your lights dim? Is it whenever you hit a deep bass note or just in general? If it occurs all the time regardless of the bass, then you're not getting enough power. If however it dims during bass notes, you should try a larger capacitor. I have 2.5F and it helped. Since you're gone this deep, you might want to get the cap. Having a larger alternator is never a waste. I forgot to ask, have you had the alternator tested before installing? |
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Bronze Member Username: TerminatermuleAustralia Post Number: 12 Registered: Nov-04 | Hi Casey, I'm with Glass and isaac on this one - the trouble you are having can only be helped by a HO alternator, not that 120 is really HO but it is better than standard. You need to sus out Isaacs questions as it holds the key to your electrical probs, if it only dims when you hit deep bass hard then a cap and good battery with high CCA rating will help you, but having said that - all this is useless unless you can charge it again, faster than you are using it. So don't be pissed off, you have taken the your first step in the right direction. i agree with Glass - the cap should be ok with what you have - again a good battery (like a yellow top optima) will aid this prob along with the cap - if you battery can't give the short term burst of current that a deep bass note needs the cap won't be able to help you much either. Especially one that small. (no offence there but it is not a massive cap) Cheers Glenn |
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Bronze Member Username: OhiopilotPost Number: 31 Registered: Nov-04 | I also concurr. Battery would be the next logical step. 120A may well be too small. Hell, that's STOCK on my little BMW Z4, and other 2-seaters I work on have close to that as well. I cringe when I hear of 70-amp alternators and such. But, back to this problem. I'd say sit down and really think about all your power draw, consider going up to 200Amp HO Alt (remember, www.mralternator.com is another choice), then look at the cap and battery. |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 5947 Registered: Dec-03 | for a 120A alt, you'll need bwtween 4ga or 2ga cable for alt to batt, batt to gnd, and batt to amps. be sure it's at least that size for all 3 areas. also make sure your amp gain is set properly and not just maxed out to compensate for power. |
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Silver Member Username: CarguyPost Number: 483 Registered: Nov-04 | Hey Mooooooorey (I like oooos), Glass, and Ray, it's nice to see people helping out without cussing or calling people "dickhead". I give your guys thumbs up. |
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New member Username: KrankitupPost Number: 4 Registered: Nov-04 | Yeah, 120A was the largest I could find without getting a custom one. The lights only dim when the bass hits. I un-bridged my amp until I have enough money to buy more. It doesn't sound as good but the lights don't dim. What would you guys suggest, a larger cap or battery first? The cap is a lot cheaper. I've found a 1-farad that I can hook in line with my .5 for $65. |
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New member Username: KrankitupPost Number: 5 Registered: Nov-04 | BTW I really appreciate everyone's help. |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 5957 Registered: Dec-03 | http://www.wickedcases.com/caraudio/capacitors.html http://www.wickedcases.com/caraudio/charging.html those two articles should tell you everything you need. If not, let me know what I can clarify. |