maybe the alternator is slowly dying

Ms5490renegade · **Posted:** Fri May 29, 2009 12:15 am

im getting a whine sound from my alternator that is directly related to rpms. is it dying? i dont seem to be having any power issues. if cost is no option, whats the best aftermarket alternator available. i think in the future i want to run 15-20 lights total

tumanator · **Posted:** Fri May 29, 2009 12:20 am

Well if your gonna wanna run a lot of power I think the best alternator you can get as far as i know is the "Mean Green." I'll post a link below, they cost a penny, but they look cool, and from my experience, last and function well.

http://www.autopartswarehouse.com/details/QQJeepQQLibertyQQMean_GreenQQAlternatorQQ20032005QQMG1387.html

Ms5490renegade · **Posted:** Fri May 29, 2009 12:24 am

this would be my first issue since i stopped letting my wallet get abused by the dealership. 4 hundred isnt bad. how long do alternatiors typically last?

Guest · **Posted:** Fri May 29, 2009 12:30 am

Forever!

In all seriousness, they're hit-and-miss.
ThunderbirdJunkie has 130k on his

tumanator · **Posted:** Fri May 29, 2009 12:41 am

Yea honestly I personally wouldn't spend the money on that alternator, you can buy one of the $160 ones that'll do as much for just as long. As ThunderbirdJunkie said, it's electrical, so it's hit and miss, it depends on the quality of manufacturing for products that make up the alternator, and they can literally vary from one to another coming off the line. Also remember just upgrading the alternator doesn't mean more power, the power pull is set by several bottlenecks, the battery being the first, most batteries have a maximum amp output. Others being cabling, fuses, age and quality of components. So just buying a $400 amp won't necessarily do you much good, but if your running a tun of electrical components all the time it may not be a bad idea.

Though i'm not saying don't get the Mean Green, it is an awesome alternator, just add up your needs vs/ what you have and see what you really need.

Ms5490renegade · **Posted:** Fri May 29, 2009 12:42 am

if i got the stock renegade alt and ran dual batteries would that possibly extend the life? i think mine got demolished by the massive amounts of power i draw on a daily basis. 2 batteries and i have a 2 farad cap on my subs should keep the life time up right? would a video with sound help determine if its dying or if im just hearing dirty water noise?

tumanator · **Posted:** Fri May 29, 2009 12:54 am

Unlike what some people think, the alternator does not run the vehicle after the initial startup, the battery always run the vehicle, the alternator just recharges it. In the electrical circuit, the battery is acting as flow controller and buffer, because the alternator doesn't provide a constant consistent stream of regulated power. Such as when people connect power components directly off any power tap (grid AC, solar panel, alternator, ect) they need a regulator and typically a battery to provide consistent current. In your jeep if your running a hot sound system (which it sound's like you are) your just running your amp harder and more often (the computer just uses the amp to charge the battery when it detects drains) so by common law the more you use it, the quicker it will wear out.

You should add up the total amp draw, from you radio / speakers, all your lights, and whatever the stock draw is of the jeep components ( I asked someone about that before on here but I don't remember what the answer was.) Compare the total amp draw of your components to the capable output of your battery(s) and your alternator. If your draw is substantially more than the stock alternator(136 i belive) look at the renegade's (160 i believe) if your drawing a lot more than that look at something better. Also just check to make sure your not overdrawing a battery (I seriously doubt it) but it wouldn't hurt to do the math anyway.

Now to clarify when you add up all your draw, remember that your probably not going to be drawing all this power ALL the time, and most likely for short bursts, you can go past your capable output very easy and the alternator can keep up, it'll draw of the batter and the amp will charge during down times. So think of what your Full Time use is.

tjkj2002 · **Posted:** Fri May 29, 2009 9:07 am

tumanator wrote:

Unlike what some people think, the alternator does not run the vehicle after the initial startup, the battery always run the vehicle, the alternator just recharges it. In the electrical circuit, the battery is acting as flow controller and buffer, because the alternator doesn't provide a constant consistent stream of regulated power. Such as when people connect power components directly off any power tap (grid AC, solar panel, alternator, ect) they need a regulator and typically a battery to provide consistent current. In your jeep if your running a hot sound system (which it sound's like you are) your just running your amp harder and more often (the computer just uses the amp to charge the battery when it detects drains) so by common law the more you use it, the quicker it will wear out.

You should add up the total amp draw, from you radio / speakers, all your lights, and whatever the stock draw is of the jeep components ( I asked someone about that before on here but I don't remember what the answer was.) Compare the total amp draw of your components to the capable output of your battery(s) and your alternator. If your draw is substantially more than the stock alternator(136 i belive) look at the renegade's (160 i believe) if your drawing a lot more than that look at something better. Also just check to make sure your not overdrawing a battery (I seriously doubt it) but it wouldn't hurt to do the math anyway.

Now to clarify when you add up all your draw, remember that your probably not going to be drawing all this power ALL the time, and most likely for short bursts, you can go past your capable output very easy and the alternator can keep up, it'll draw of the batter and the amp will charge during down times. So think of what your Full Time use is.

Actually you are 99% false,the alternator does recharge the battery but after the starter stops turning and the engine is running the battery does not power anything it is all on the alternator.The alternator supplies all the power to the vehicle when the engine is running and is regulated all the time by the voltage regulator that is built into the PCM,plus the battery must be installed to complete the charging system circuit sinc ethe KJ's alternator needs 12 volts to make power.When the amp draw is greater then what the alternator can handle the battery supplies the extra amps.Since the PCM totally controls what the alternator puts out adding a higher amp alternator on a KJ is useless unless you get the PCM reprogrammed.Adding dual batteries can shorten a alternators life due to the added stress of charging 2 batteries.

Just get a new Renny 160amp alternator,stay away from any one bought from Advance Auto,Autozone,and Checkers,basically get a OEM one.All your offroading in mud and water is the cause of the early demise as is the constant high load drain from your stereo.

Ms5490renegade · **Posted:** Fri May 29, 2009 9:37 am

tjkj2002 wrote:

tumanator wrote:

Unlike what some people think, the alternator does not run the vehicle after the initial startup, the battery always run the vehicle, the alternator just recharges it. In the electrical circuit, the battery is acting as flow controller and buffer, because the alternator doesn't provide a constant consistent stream of regulated power. Such as when people connect power components directly off any power tap (grid AC, solar panel, alternator, ect) they need a regulator and typically a battery to provide consistent current. In your jeep if your running a hot sound system (which it sound's like you are) your just running your amp harder and more often (the computer just uses the amp to charge the battery when it detects drains) so by common law the more you use it, the quicker it will wear out.

You should add up the total amp draw, from you radio / speakers, all your lights, and whatever the stock draw is of the jeep components ( I asked someone about that before on here but I don't remember what the answer was.) Compare the total amp draw of your components to the capable output of your battery(s) and your alternator. If your draw is substantially more than the stock alternator(136 i belive) look at the renegade's (160 i believe) if your drawing a lot more than that look at something better. Also just check to make sure your not overdrawing a battery (I seriously doubt it) but it wouldn't hurt to do the math anyway.

Now to clarify when you add up all your draw, remember that your probably not going to be drawing all this power ALL the time, and most likely for short bursts, you can go past your capable output very easy and the alternator can keep up, it'll draw of the batter and the amp will charge during down times. So think of what your Full Time use is.

Actually you are 99% false,the alternator does recharge the battery but after the starter stops turning and the engine is running the battery does not power anything it is all on the alternator.The alternator supplies all the power to the vehicle when the engine is running and is regulated all the time by the voltage regulator that is built into the PCM,plus the battery must be installed to complete the charging system circuit sinc ethe KJ's alternator needs 12 volts to make power.When the amp draw is greater then what the alternator can handle the battery supplies the extra amps.Since the PCM totally controls what the alternator puts out adding a higher amp alternator on a KJ is useless unless you get the PCM reprogrammed.Adding dual batteries can shorten a alternators life due to the added stress of charging 2 batteries.

Just get a new Renny 160amp alternator,stay away from any one bought from Advance Auto,Autozone,and Checkers,basically get a OEM one.All your offroading in mud and water is the cause of the early demise as is the constant high load drain from your stereo.

how can i prevent an early death in the future? is there a water proofing method?

tumanator · **Posted:** Fri May 29, 2009 9:56 am

actually that's not true either, any extra lights, amplifiers for speakers, are ran straight off the battery terminal. If you bypass the battery and connect them to the alternator your going to blow them because you loose the regulated voltage, and regulated amp flow. Yes the alternator does "run" the vehicle when the engine is operating, but the flow of current passes over the battery and fuse boxes for regulation.

Lets go EE for a sec here, the battery and alternator are a parallel circut that connect to a serial power backbone circuit. If the serial pull is 20a and time A then there is going to be no drain on the battery all the power needed can come from the amp. At time B you kick in all power systems in the vehicle and pull 200a, the alternator can't keep up the parallel part of the circuit (the battery) covers the extra amps with a drain, at time C the power falls back down, the alternator will still provide power to the sytem and supply the charge back to the battery for it's drain. I can see how what I said is wrong, i was just trying to make it understandable. You can run your vehicle completely with just the alternator if the battery it dead, it's just a bypass in the parallel circuit. And it's the same thing if the alternator is not operational all the power will come from the battery, see that is the beauty of a parallel circuit.

The power output is connected to a serial circuit (if you cut the power cable off the battery terminal everything dies.) But the power being provided does not come off the alternator, it comes off the parallel circuit with the alternator and battery. This allows you to run amplifiers and extra lights, because in between the pulses of power the alternator provides from the parallel circuit to the serial circuit, the battery picks up the extra amps to make it a continuing and regulated flow. If the alternator is providing more power to the circuit than is needed, the battery will then absorb the extra power still providing the regulated flow.

This being said if your peak pull is say 200a, you can still run it off the renegade 160a alternator because the peak beats are caught by the parallel circuit and a drain / charge cycle happens. This is how they were engineered and designed. But if your running a wal-mart or something with it then you need to go bigger.

FreedomKJ · **Posted:** Fri May 29, 2009 9:59 am

You can waterproof the connectors, but it's really the mud and the silt in the water that's killing it, and there's nothing you can do to prevent that other than stay out of it.

The other option is to get one of those Autozone/Advanced/O'Reilly's/etc. alternators with the lifetime warranty, and when it starts going out just clean it up really good and take it back.

tumanator · **Posted:** Fri May 29, 2009 10:35 am

Actually a good idea, disconnect the battery and coat the battery posts, and the wire terminals with regular petroleum Vaseline, this actually does waterproof the terminal and the copper wire from water and rust. Though the downside if you coat it to thick it will tend to catch more dust. I've always done it, because it prevents oxygen from reaching the metals and stops corrosion on the terminal and rust on the wire. Just don't gob it on, you only a thin coat.

tjkj2002 · **Posted:** Fri May 29, 2009 9:19 pm

tumanator wrote:

actually that's not true either, any extra lights, amplifiers for speakers, are ran straight off the battery terminal. If you bypass the battery and connect them to the alternator your going to blow them because you loose the regulated voltage, and regulated amp flow. Yes the alternator does "run" the vehicle when the engine is operating, but the flow of current passes over the battery and fuse boxes for regulation.

Lets go EE for a sec here, the battery and alternator are a parallel circut that connect to a serial power backbone circuit. If the serial pull is 20a and time A then there is going to be no drain on the battery all the power needed can come from the amp. At time B you kick in all power systems in the vehicle and pull 200a, the alternator can't keep up the parallel part of the circuit (the battery) covers the extra amps with a drain, at time C the power falls back down, the alternator will still provide power to the sytem and supply the charge back to the battery for it's drain. I can see how what I said is wrong, i was just trying to make it understandable. You can run your vehicle completely with just the alternator if the battery it dead, it's just a bypass in the parallel circuit. And it's the same thing if the alternator is not operational all the power will come from the battery, see that is the beauty of a parallel circuit.

The power output is connected to a serial circuit (if you cut the power cable off the battery terminal everything dies.) But the power being provided does not come off the alternator, it comes off the parallel circuit with the alternator and battery. This allows you to run amplifiers and extra lights, because in between the pulses of power the alternator provides from the parallel circuit to the serial circuit, the battery picks up the extra amps to make it a continuing and regulated flow. If the alternator is providing more power to the circuit than is needed, the battery will then absorb the extra power still providing the regulated flow.

This being said if your peak pull is say 200a, you can still run it off the renegade 160a alternator because the peak beats are caught by the parallel circuit and a drain / charge cycle happens. This is how they were engineered and designed. But if your running a wal-mart or something with it then you need to go bigger.

Just to correct you the alternator voltage is always regulated coming off the big positive alternator lead that is directly attached to the positive battery terminal.The only reason everyone attaches AUX electrical stuff directly to the battery is it is almost always easier to attach to then the alternator.The battery in our system does not add to the system total amp output until the alternator is overrun.

Right from the FSM.................

Battery system

Quote:

The battery system is designed to provide a safe,
efficient, reliable and mobile means of delivering and
storing electrical energy. This electrical energy is
required to operate the engine starting system, as
well as to operate many of the other vehicle accessory
systems for limited durations while the engine
and/or the charging system are not operating. The
battery system is also designed to provide a reserve
of electrical energy to supplement the charging system
for short durations while the engine is running
and the electrical current demands of the vehicle
exceed the output of the charging system. In addition
to delivering, and storing electrical energy for the
vehicle, the battery system serves as a capacitor and
voltage stabilizer for the vehicle electrical system. It
absorbs most abnormal or transient voltages caused
by the switching of any of the electrical components
or circuits in the vehicle.

Charging system.....

Quote:

The charging system is turned on and off with the
ignition switch. The system is on when the engine is
running and the ASD relay is energized. When the
ASD relay is on, voltage is supplied to the ASD relay
sense circuit at the PCM. This voltage is connected
through the PCM and supplied to one of the generator
field terminals (Gen. Source +) at the back of the
generator.
The amount of DC current produced by the generator
is controlled by the EVR (field control) circuitry
contained within the PCM. This circuitry is connected
in series with the second rotor field terminal
and ground.
A battery temperature sensor, located in the battery
tray housing, is used to sense battery temperature.
This temperature data, along with data from
monitored line voltage, is used by the PCM to vary
the battery charging rate. This is done by cycling the
ground path to control the strength of the rotor magnetic
field. The PCM then compensates and regulates
generator current output accordingly.
All vehicles are equipped with On-Board Diagnostics
(OBD). All OBD-sensed systems, including EVR
(field control) circuitry, are monitored by the PCM.
Each monitored circuit is assigned a Diagnostic Trouble
Code (DTC). The PCM will store a DTC in electronic
memory for certain failures it detects. Refer to
Diagnostic Trouble Codes in; Powertrain Control
Module; Electronic Control Modules for more DTC
information.
The Check Gauges Lamp (if equipped) monitors:
charging system voltage, engine coolant temperature
and engine oil pressure. If an extreme condition
is indicated, the lamp will be illuminated. This is
done as reminder to check the three gauges. The signal
to activate the lamp is sent via the CCD bus circuits.
The lamp is located on the instrument panel.
Refer to 8, Instrument Cluster for additional information.

Alternator......

Quote:

As the energized rotor begins to rotate within the
generator, the spinning magnetic field induces a current
into the windings of the stator coil. Once the
generator begins producing sufficient current, it also
provides the current needed to energize the rotor.
The stator winding connections deliver the induced
AC current to 3 positive and 3 negative diodes for
rectification. From the diodes, rectified DC current is
delivered to the vehicle electrical system through the
generator battery terminal.
Although the generators appear the same externally,
different generators with different output ratings
are used on this vehicle. Be certain that the
replacement generator has the same output rating
and part number as the original unit. Refer to Specifications
and see Generator Ratings for amperage
ratings and part numbers.
Noise emitting from the generator may be caused
by: worn, loose or defective bearings; a loose or defective
drive pulley; incorrect, worn, damaged or misadjusted
fan drive belt; loose mounting bolts; a
misaligned drive pulley or a defective stator or diode.

maybe the alternator is slowly dying

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