scotty13

Worst case senario:

Headlights and brights along with brakes, signals,and gauges
aftermarket fog lights
A/C
3 Electric fans (no mechanical, 2 small fans on front of condenser)
Wipers
power windows
after market stereo and amps (2 500W)


on a warm, rainy night at a stop light idling arround 900rpm...the voltage will drop below 12v to somewhere near 10v. The stereo drops out and the lights go very dim and i must put the car in neutral just to bring the voltage up to near 12V.
i currently have a 120A alternator. Is anybody using a very high output alternator on a C3? near 200A+?

big_G

120 watts should be enough. Check with an alternator rebuilding shop and they can modify the turn-on point in the regulator, like the alternators cop-cars use....maybe you can put a smaller diameter pulley on it.

ratflinger

Well you could underdrive the alt & get it to output more juice at lower engine speed, but I don't know how long it would last before burnout. Of course you could always turn the darn stereo down! 2x 500w amps?? Either you are deaf or soon will be. No offense intended, but don't pull up beside me that thing cranked. On the serious side, I am inclined to think that with that big of an amp increase (120a to 200a which is apx a 65% power increase) you would be in danger of seriously overloading the wiring. A short could be quite catastrophic.

scotty13

ratflinger: The extra amperage would not be pulled through the existing stock wiring because there are no added components to create the draw. All aftermarket stereo components (amps) are wired direct to the batery. A correct heavy gauge wire would be dropped back to the starter in place of the stock gauge wire as the charging lead.


btw...400A+ alternators have been put in SUV's to power stereo systems. 1000W is on the low side of aftermarket car stereo systems.

Are there any cars that use a higher output alternator that i could use? Brackets and pulleys could be fabricated/ swapped.

fej

I would do the basics first ... clean the terminals on the battery, all of your grounds etc etc. Then I would add a capacitor ( I see no reason to go above 1.5 farads but if you want 10 go for it) to help lessen the stereo drain pull on the alternater and battery. With the cap it basically takes your electrical system pull back to near stock levels. I am not sure what battery you are running but I would look into an Optima Red or Yellow top (have a yellow coming myself) which is better suited to high discharge/charge use than conventional batteries.

If all of these measures fail I would look into getting a police issue alternator or have yours rebuilt and upgraded. Not sure I would go to the smaller pulley or not .. might be worth while but its more wear on the unit itself.

G'luck
Fej

scotty13

The alternator that i have now is fried (tested by parts store). Does anybody know where I can get at least a 150A alternator? Where would I get a Police built alternator?

pentavolvo

Look into doing the big 3 as well man especially with the new alternator

scotty13

"the big 3" ???

ICULUKN-C5

He is refering to the "Big 3" wires to upgrade:

1) Battery negative to chassis
2) Alternator to battery positive
3) Chassis to engine


I grabbed this off sounddomain.com

Now, I suppose it would help if I explained what each of these wires does, and to do that I would like to paraphrase an explanation by IMTfox from a while ago: Think of your vehicle's charging system as two different circuits, one consisting of your amplifier and your battery, and the other consisting of your alternator and your battery. The current in your electrical system flows from your positive battery terminal to your amp, from your amp's ground to the chassis, and then from the chassis back to the negative battery terminal. But how does it get to the positive terminal in the first place? That's where the alternator comes in. Current in the second circuit flows from your alternator's positive post to the battery's positive terminal, then from the battery's negative terminal to the chassis, and from the chassis back to the block, which happens to be the grounding point for your alternator.

So, from your battery, you have the power wire going to the power terminal on your amplifier and then your amplifier is grounded to the chassis of the vehicle. From here the current needs a way to get back to the negative battery terminal, and that way is through the first of the "Big 3," the battery negative to chassis wire. Upgrading this wire will "upgrade" the circuit between your battery and your amp by giving the current a larger path to flow through to get back to the battery.

Now, think of your alternator as the battery and your battery as the amp. From the positive post on your alternator, you have the second of the "Big 3," the alternator to battery positive wire supplying "power" to your battery. From there the battery, just like your amp, is grounded to the chassis through the wire mentioned in the previous paragraph. Again, the current needs a way to get from the chassis back to the alternator's "negative terminal" and that way is through the last of the "Big 3," the chassis to engine wire. Since your alternator is most likely mounted to your engine block using a metal or conductive mounting bracket, you can simply add your new wire from the chassis to one of the mounting posts for the alternator. Upgrading these two wires will "upgrade" the circuit between your alternator and your battery, again giving the current a larger path to flow through.

----------------------------------------------

Now that you understand exactly what the "Big 3" do, it's time to upgrade them to a larger gauge wire. You can use regular power wire from installing your car audio equipment, ring terminals, and crimping equipment just the same as you would for any other install. Let's start with the first of the "Big 3," the battery negative to chassis wire:

1) Disconnect your battery's negative terminal and get the stock wiring out of the way. You might have to cut it and crimp a new ring terminal onto it. I found it helpful to use aftermarket battery terminals with multiple ports on them also.

2) Scrape away the paint and drill the hole for your connection of the larger wire, or connect it to the stock grounding point. Either way you do it, make sure it is bare chassis metal, not covered by paint, and that the connection is as tight and secure as possible:

3) Secure the new wire to the chassis and reconnect the vehicle's stock chassis ground, but DON'T reconnect the vehicle's negative battery terminal yet! You may find it helpful to cover the negative battery terminal with a cloth or other non-conductive material and just lay the terminal on it until you're ready to reconnect it later.

Moving on to the next of the "Big 3," let's upgrade the alternator to battery positive wire:

4) Locate the vehicle's alternator and look for a terminal post connected to it. The post shouldn't be hard to find. It should have only one wire connected to it, and it should lead to the positive terminal on the battery, possibly through the fuse box.

5) Disconnect the stock alternator to battery positive wire from the positive post and connect it to the post again with the new wire added.

6) Run the wire either through your fuse box if applicable or through a fuse. The fuse should be sized to match the max ampacity of your wire, not the output capability of your alternator. As you can see I just went through the fuse box, so my upgrade is probably not making as much of a difference as it could if it were fused externally, but my alternator is capable of withstanding the draws anyway so I'm not particularly worried about it. If I ever begin to see a problem w/ current draws, I will probably fuse the wire externally with a 300A or so fuse...

7) From the fuse, connect the wire to the positive terminal on your battery, again, leaving the stock wiring connected when you're done. The picture below shows the alternator to battery positive wire run from the alternator through my fuse box to the positive battery terminal.

Last, let's move to the chassis to engine wire: (Again, because your alternator is grounded to the block, all you need to do is find a bolt somewhere on the block and connect it to the chassis. The alternator's mounting bracket is usually a good place to find these bolts).

8) Again, either drill a new hole or connect this wire to the stock chassis ground. From the chassis ground, run the wire back to one of the mounting posts for the alternator (or to a bolt on the engine block).

9) That's it! You're done. Reconnect the vehicle's negative battery terminal and check out the difference! Below is a shot of the "Big 3" upgraded in my car. The other wire you see coming out of the battery's positive terminal is obviously my amp's power wire.

Helpful hints:

1) Leave the stock wiring attached after you're done. Don't replace the stock wiring, add onto it. Current will take the path of least resistance anyway, so replacing the stock wire will only make more work for yourself.

2) When fusing your alternator to battery positive wire, fuse it toward the battery end of the wire. As IMTfox points out later in this thread, the battery will explode if it's overloaded, while the alternator will only burn out its regulator which won't cause much damage except to the alternator itself. Exploding batteries are no fun!

3) When crimping large gauge terminals for 1/0awg and sometimes even 4awg, a vice works well. Crimp one side of the terminal at a time, creating an overlapping edge. Put the boot around this and then wrap it in electrical tape if you want. the most secure connections will occur in this way.

4) Lastly, prepare all your materials and tools BEFORE you are ready to upgrade. Know what you are doing before you start so you can be done as quick as possible. The majority of vehicles have computers that will reset after the battery is disconnected for a long time and they can cause older vehicles to do strange things if they reset.

Hopefully this clears up most of the questions you had about why we upgrade the "Big 3" and how it helps to stop dimming and other electrical problems

onaqwst

i'm in the same boat...

ppi 2600 and ppi 6600
i have 2 1fared caps and doesn't seem to really do the trick.... battery upgrade with another alternator might work for me..... i was thinking about the 5 fared units...any good recommendations for a 5fared setup?



b

scotty13

Is anybody using an alternator that is not the stock style regardless of amps? Maybe a newer style?

comp

scotty13

anybody?

leolufse

if the stocker is 120 watts thats plenty. don't add a cap it will only add to the draw on the electrical system. each of your amps needs to be wired with at least 4 gauge wiring. if you have not done the big 3, that will also help. lastly, check your grounds with an ohm meter. Older fiberglass cars are not exactly ideal for good grounds. good luck

scotty13

The 120A alternator that I have on there now is a three wire. It is not stock. The stock alternator is only 63A.

knewblewkorvette

Some good advice on this post and some misleading.
Everyone who mentioned the big 3 like ICULUKN-C5 and leolufse (except he meant 120 amps ) is on the right track. A 120 amp altenator (while working ) is plenty for 1000 watts. Many companies such as Stinger makes aftermarket altenators for cars, do some research on the net and I'm sure you'll find one.

onaqwst
I have the G.A.P. capicators in my C5 and white Talon TsiAWD. Both have a the 15 Farad model in them though they make smaller models. They are not cheap but you get what you pay for

onaqwst

i'll spend some cash to make sure my electrical is right...... this is one area that you can't screw with...... when i was 16, i almost torched my 91 caliver cause my wiring wasn't right....... last time i tried to half azz a car audio setup.........

15 fared..... crazy.... i'll look into that...thanks

scotty13

Got it fixed. I replaced the stock type SI10 (rebuilt to put out more amps) with a CS130 140A. It pushes 14V to the car even when under full load at idle. No bracket modification needed, just a new pigtail for the 2 sensor wires (picked up from autoparts place along with alternator). Also upgraded the main pos lead from the alt with a 4 gauge wire.