Stock 105amp alt not cutting it? Charging system fault

jmX · 06-21-2002, 09:18 PM

So, I've got a medium sized stereo setup in my C5, and when I have it cranked up reallly loud and am playing songs with lots of continuous bass, the alternator simply can't keep up. At mild volumes everything is fine. This only happens at night with the lights on, and the engine RPMS have nothing to do with the problem. I can get it to happen with the engine at 4000rpms constantly, or 1500...

At this point, I'm assuming I'm just hitting the limit of the alternator. What are my options for a new higher output one? I dont need much...maybe a 160amp one would be sufficient. Links/prices?

Kale · 06-21-2002, 09:19 PM

What's the total RMS power of amps? current draw if you know it?

thode · 06-21-2002, 09:58 PM

What is your voltage at ???

You may need to use a farad cap to get the sudden voltage your amps require. Cheaper made amp don't have very much onboard storage of power for sudden bass hits. Ther fore cause your headlight to pulse in brightness.

If your voltage stay's above 13.3 you are ok with your alt.
So just get a 1 or 1/2 farad cap and install it close to your amps.
Cost about 100.00 but it is worth every penny.

The constant pulsing of power will cause premature computer and ground problems if not corrected.

:cool:

AP · 06-22-2002, 12:55 AM

Quote:

If your voltage stay's above 13.3 you are ok with your alt.

:yesnod: ... if you have high enough voltage you should try a capacitor first ...

jmX · 06-22-2002, 03:00 AM

The RMS I beleive of my 2 amps is around 520 watts right now. I have a 4x200 PPI amp bridged to a 2ch to power the front speakers, and a 2x320 PPI bridged to power the 1 12" JL sub.

During loud songs, the voltage slowly drops from 14.2 down to around 12.5-13.0 range. I can watch the guage drop slowly over time when a loud song comes on, and if a break in the music happens, the guage crawls back up. Which I'd guess to mean the alt just cant keep up with the demand.

Before I had the amps bridged everything was fine...it was using a lot less power then (but obviously sounded a lot worse).

_Nomad_ · 06-22-2002, 04:20 AM

First off you have a 110-amp stock alt in your C5. It does sound like alt strain. Before purchasing a high output alt or a cap upgrade your stock electrical wiring first. You will need to do this anyway if you get a HO alt and since the cost is minimal and might solve your problem it is well worth doing.

Run no less than 4-gauge power wire (the larger the gauge the better the results) from positive battery terminal to alt. Fuse it with an ANL fuse at what the alt is rated at. Then run no less than 4-guage ground wire from the negative battery terminal to the chassis and from the engine block to the chassis. Leave the stock wiring alone just run this new wire in addition to it. I would suggest you purchase top mount battery terminal connecters for all of your stereo, and electrical upgrade wiring and leave the side post mounts for your stock wiring.

You will notice a significant increase in voltage from your alt. If you still have trouble with excessive voltage dropping then upgrade the alternator, you will already have the wiring upgraded. In the case of severe voltage loss a cap will only harm you by making things worse. If you drop below 12v then you have a serious problem and will require a higher output alt.

Good luck. :seeya

AP · 06-23-2002, 01:52 AM

The^Nomad is right ... it could be that ... and it shouldnt cost more that 20 to find out ... I know someone a while back did that on the forum and it helped ... I think he went with 4 ga ... or was it 2? ... but either way ... try it ...

[Modified by NewVetteLover, 11:24 PM 6/23/2002]

gcrouse · 06-23-2002, 06:16 AM

Quote:

upgrade your stock electrical wiring first. Run no less than 4-gauge power wire (the larger the gauge the better the results) from positive battery terminal to alt

Yes, there ain't no way that skinny little factory installed wire is going to carry even the 110A of your stock alternator. I bet the wire's getting warm.

If rewiring does help, then it sounds like the alt can't keep up. And a capacitor won't help- it only supply instantaneous power (keeps the lights from dimming on bass thumps) then must recharge. It will not correct your problem: you're drawing more current than the alternator provides so it's pulling from the battery. Find out the max current draw of those amps and add to the rest of the electrical system that's operating at that same time.

AP · 06-24-2002, 01:27 AM

How much would it cost to get a new Alt? I think that my friend may need one ... we did the wire upgrade ... and the math behind the Amps ... and they draw 100 alone ... another alt is probably required ...

gcrouse · 06-24-2002, 04:37 AM

For you C4 folks- check out Quick Start. They make a CS-130/130D up to 170 amps ($189) by using cooler housings, larger bearings, high current regulators:

http://www.alternatorparts.com/cs130_&_cs130d_alt.htm

They also sell a kit to upgrade yours to 140 amp for $79:

http://www.alternatorparts.com/7130_7140%20.htm

AP · 06-24-2002, 01:44 PM

Quote:

For you C4 folks- check out Quick Start. They make a CS-130/130D up to 170 amps ($189) by using cooler housings, larger bearings, high current regulators:

http://www.alternatorparts.com/cs130_&_cs130d_alt.htm

They also sell a kit to upgrade yours to 140 amp for $79:

http://www.alternatorparts.com/7130_7140%20.htm

Got any for the C5?

gcrouse · 06-24-2002, 03:27 PM

Quote:

Got any for the C5?

I bet those same folks have them. Do you know what the model# / case style is?

RDRH8R · 06-24-2002, 03:39 PM

An additional battery would also cure the problem. Try the Streetwires gel cell battery. It is small (7"x7"x5") so easily installed. Then get a Pac200 to install between the batteries. Your stock alternator will have no problem keeping them both charged (with the Pac200 installed). This also gives you the ability to leave the stereo playing with the car off without the threat of your car not starting.

_Nomad_ · 06-24-2002, 04:50 PM

Quote:

An additional battery would also cure the problem. Try the Streetwires gel cell battery. It is small (7"x7"x5") so easily installed. Then get a Pac200 to install between the batteries. Your stock alternator will have no problem keeping them both charged (with the Pac200 installed). This also gives you the ability to leave the stereo playing with the car off without the threat of your car not starting.

:nonod:

Unless the charging system is capable of charging everything in the car sufficiently an additional battery will only be the death of his system, not to mention expensive. In cases of insufficient voltage you must fix the root of the problem. The heart of a cars charging system is the alternator and the wires that deliver its voltage. He is not running the kind of power to justify a second battery in the first place. That would be overkill.

Any electrical component in a car, in this case the stereo system, looks to the battery first as its source of potential. Once the battery is depleted it looks for the next closest source of potential, which could be a cap, another battery, then the alternator. If you don’t have a cap or second battery it goes straight for the alternator. Now that the battery(s) and/or cap has been discharged the alternator then has to recharge them all as well as feed voltage to the cars electrical system (and keep up with the stereo). As you can imagine that would certainly put a strain on an insufficient alternator to keep up. If the alternator falls short of supplying power then you have a voltage drop, which in minor cases causes the headlights to dim, and in more severe cases causes electrical system damage to your car and stereo components. Not to mention leaving you stranded somewhere. Keep in mind he said his voltage got as low as 12.5v. His amps are starving for power and his music and components are suffering for it. Adding anything more to his electrical system that draws power will be counterproductive in this situation.

Like I said before I suggest you upgrade your electrical system wiring as your first step. It is the least expensive and does yield results, especially if you are only dropping as low 12.5v, and again, it will have to be done anyway if you get a HO alt. If that isn’t enough then upgrade the alternator. Once you have completed your electrical system upgrades then I would recommend you invest in a gel cell battery like the Optima Yellow Top when your current battery eventually dies, no need in spending the money till you need it. For the size of your system you will not need two batteries.

Here is a link to find a good High Output alternator for your Vette.
http://www.alternatorparts.com/

Here is a link for Optima Battery information.
http://www.optimabatteries.com/products/index.asp

Hope this helps, good luck. :seeya

RDRH8R · 06-28-2002, 02:43 PM

Quote:

:nonod:

Unless the charging system is capable of charging everything in the car sufficiently an additional battery will only be the death of his system, not to mention expensive. In cases of insufficient voltage you must fix the root of the problem. The heart of a cars charging system is the alternator and the wires that deliver its voltage. He is not running the kind of power to justify a second battery in the first place. That would be overkill.

Any electrical component in a car, in this case the stereo system, looks to the battery first as its source of potential. Once the battery is depleted it looks for the next closest source of potential, which could be a cap, another battery, then the alternator. If you don’t have a cap or second battery it goes straight for the alternator. Now that the battery(s) and/or cap has been discharged the alternator then has to recharge them all as well as feed voltage to the cars electrical system (and keep up with the stereo). As you can imagine that would certainly put a strain on an insufficient alternator to keep up. If the alternator falls short of supplying power then you have a voltage drop, which in minor cases causes the headlights to dim, and in more severe cases causes electrical system damage to your car and stereo components. Not to mention leaving you stranded somewhere. Keep in mind he said his voltage got as low as 12.5v. His amps are starving for power and his music and components are suffering for it. Adding anything more to his electrical system that draws power will be counterproductive in this situation.

Like I said before I suggest you upgrade your electrical system wiring as your first step. It is the least expensive and does yield results, especially if you are only dropping as low 12.5v, and again, it will have to be done anyway if you get a HO alt. If that isn’t enough then upgrade the alternator. Once you have completed your electrical system upgrades then I would recommend you invest in a gel cell battery like the Optima Yellow Top when your current battery eventually dies, no need in spending the money till you need it. For the size of your system you will not need two batteries.

Your suggestion will work. I was just giving him other options. And adding the battey will work just fine. The "secret" is the PAC200. It allows the stereo to run off the extra battery while the cars electronics run off the main battery. The stock alternator will have not A problem keeping them both charged. I have done the install many times and have had no problems. And it is not that expensive to do. When we install an extra battery the total price usually is around $250 parts and labor. And it adds the added feature of playing the stereo while the car is not running without being concerned about it not starting.