severe voltage drop, bad alternator?

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. sparky

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.

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

Huh.Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

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.

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~

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?

Generally I don't like to recommend ebay but i like Iraggi alts

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