Curious how this is done. I would be willing to pull out my A/C and pulley to make room for a second alternator.

I have had dimming problems, and low voltage at idle while running my old small Kenwood amp. (300 RMS).

I scrapped it, and picked up a 400 watt RMS Orion amp, and a 1200 watt RMS Kicker amp.

Installed in my beater for now, but I want to get it in my camaro sometime. I have seen a few car audio shows, where some people run 2-4 alternators, so I know this can be done, I'm just not sure how to go about doing it.

Right now, I have a 140 amp stock replacement. It is about 3 years old now. I was thinking of picking up a 180 HO amp (65 amp at idle) and installing it too. I figure with the extra juice from both alternators, it will solve and future power requirements.

 

There are two alternator brackets for our cars. There is one for the left side 1985-1987. And the right is the 1988-1992. I don't know how to maintain belt operations though.

 

Just get a cap dude. My buddy's got 2 12" Fosgates with an 800 watt Fosgate amp and two caps. The system is so loud it beat a grand am with 2 JL's and 1200 watts. Since he has one cap with an electrical readout you can watch to see how much voltage you have and you wont have dimming problems. We listened to the system with the car off and the system up relativly loud for 45 minutes and the readout on the cap hardly changed, the battery was never used. Just get a cap dude, it's where it's at.

 

A cap will help the power output to the amp, but the load on the alternator will be the same(the power has to come from somewhere). You might also consider overdriving the alternator to get some extra power at idle--it's done with a different pully. Dual alternator is custom, so it will take some fabrication.

 

For 2 alts, they need to be matched in outputs, otherwise one will be hogging the load and the other will hardly be working at all, one will fail faster than the other.

 

Why not just run one high output 250AMP Alternator:

http://www.alternatorparts.com/Doubl...fier_cs144.htm

 

Expensive there. I will e-mail them and see what they all put out at idle (750 rpm)

Thanks.

 

Ive been toying with this idea as well...ive got my fans wired so they r always on and with the msd and the stereo and the headlights and all runnin its quite a load. My idea is to find an old-style 1 wire alternator with the correct direction of rotation to replace my a/c pump. Then to avoid load problems between the two, the stock one will run the car and accesories and the custom one will run to a separate battery in the trunk and power the system. Also if you plan on using two alternators hooked up together im pretty sure you need to buy a special adapter to keep from causing major problems....I cant remember what they are called but stinger used to make them for sure and other wiring companys probably do as well. I believe it balances out the loads between the two and keeps them from shorting eachother out. anyhoo anyone think twin setup idea will work o/k? Peace...Matt. Oh p.s. i have already upgraded to the 140amp iceberg and its not doing the trick.

 

Thanks for the post.

That is an interesting idea actually. Problem with another alternator is extra noise in the system. Heard it happens pretty often with HO alternators.

I too have my fans running all the time, and I know that doesn't help much either. I have the stock 50 amp alternator in my beater-prelude, and a new yellow top optima battery (running my system in there so far for now) no dimming at all.

I don't get it. I'm running a Kicker 1200.1, and a Orion 500 XTR and it can handle it fine. My camaro has seen a tiny Kenwood '600 watt' amp and it kills the lights, and the voltage drops down at idle.

Been waiting so far, but I will see what I can find in alternators which have a high output at idle, and also look into overdrive pullies, if anyone makes them.

 

hey heres a thought, buy serpentine brackets for like a 88-92 f-body and take all the accesories out and replace them with 4 alternators

 

Just get 1 or 2 caps, that'll take care of all your dimming problems and save yourself the trouble of setting up a custom 2 alternator job. Or even put a 2nd deep cycle battery in the trunk.

 

Have you considered replacing/upgrading the ground strap to get a better ground connection to the chassis?

 

For increased idle voltage output from the alternator get a smaller pulley from www.alternatorparts.com
If you want to run 2 alternators anyways get an isolating circuit (through the formentioned company) and install the 2nd alternator where the air pump is. I have my alternator down there right now and have the stock location free for anything right now. This is of course for the later serp. pulley setup, not the older v-belt.
Or to be cheap you could run 2 batteries with the above mentioned alternator placements. That way you could run the engine and OEM off of one pattery and a deep cycle for the stereo.

 

There is alot of misinformation about what capacitors do. On a basic level, they are essentially a very fast-acting battery (in a dc circuit anyway). By putting a big cap right near your amplifiers what you do is give the amps someplace to draw alot of power from for a very short ammount of time when a hard note hits. This will help problems with lights dimming. If all of the power and ground wiring in your system is big enough, you do not need a cap at all (this point could be argued).

A cap will not however let you get by with too small of an alternator. Before adding a second alternator I would reccomend a smaller pulley on the alt or a larger one on the crank to get your alternator speed up, this will help charging alot, espicially if you idle while playing music.

 

right on about the wire sizing. notice most factory alternators come with small teeny wiring from the alt to the batt...

i had some serious battery drain probs with a teeny 800W and 2 12's...

yes I added a CAP 1 farat but my battery was still draining over time.

the fix? 4 guage wire off the alt hot to the battery. no more problems.

 

If you put a 1farad with only a 800watt amp going then your battery shouldn't drain, unless you got a pos cap or you wired something wrong. 1 farads are good for 1000watts I'm pretty sure... Instead of adding a second alternator and making things difficult why not just get a 200amp alternator, then a cap if the problem still persists. I would think a second alternator would be a pain to setup on the belt, and a pain to wire right so your not killing things else where.