If you are running your audio system with a slightly higher load than you alternator can provide, will/can your alternator go bad as a result?
I'm driving a 2001 Saturn SC2 with two amps, PPI 5440 (440 watts) and an Alpine MRP-F600 (600 watts). Not sure what the actual power draw is on those amps. When I run my sytem hard, there is very little (if any) dimming of lights.
I'm paying $$$ to get my alternator replaced right now, wondering if there is a correlation.
If there is a correlation, would running the Big 3 help the problem, or make it worse?
I'm driving a 2001 Saturn SC2 with two amps, PPI 5440 (440 watts) and an Alpine MRP-F600 (600 watts). Not sure what the actual power draw is on those amps. When I run my sytem hard, there is very little (if any) dimming of lights.
I'm paying $$$ to get my alternator replaced right now, wondering if there is a correlation.
If there is a correlation, would running the Big 3 help the problem, or make it worse?
Yes, the alternator will die if you are drawing more than its rated current, continuously. The battery will lessen the load at first but eventually the alternator will carry the full load and give out. I've got an excellent + and ground system on mine and can toast my alternator in a heartbeat with the amps I have. I'll eventually get an upgraded alternator, but for now I just keep the volume at a respectable level.
well, how many amps is the alt. rated for and how many amps do your amplifiers draw? That's what you need to know to answer your question. What are the amplifiers individually fused at? It could just be a coincidence that your alt. died because they are items that wear out. Of course, if you're amplifiers are too much of a load on the alt. it will stress the alt. components and it can fail.
If you're not flattening your battery over time then the alternator is OK. There's no real problem with drawing down the charge on the battery a bit if it gets recharged, it really depends on the usage. If the total average power draw is more than the alternator produces and the system runs all the time the engine is running then you've got trouble.
It's a judgement call... time was you could have checked the battery condition with a hygrometer, but these days batteries are sealed, so it's probably a question of running a couple weeks with the new alternator and watching for a weak start in the morning.
w
It's a judgement call... time was you could have checked the battery condition with a hygrometer, but these days batteries are sealed, so it's probably a question of running a couple weeks with the new alternator and watching for a weak start in the morning.
w
ppia600 said:
hmmm. I have three amps with a main wafer fuse at 150A. my alt is around 65A and I turn up the volume once in a while at night (engine running at traffic stops, voltage sags to 12.2V) but my alt is still working. not sure for how long though.
BTW, I replaced the stock batt with a bigger size used for trucks. 
Those car usually use Delco's cs 130 or 130D Line. Both are junk. Delco's CS144 line where much better alternators. Most of the time if you can find a 144 series that fits on your car you will have a serious upgrade in power. The 130's are rated at 105 amps and do about 60 when hot. The 144's are rated for 140 amps and do about 100-110 when hot.
djQUAN said:
Yeah, this sounds a bit alarming if the battery is good, but it's not a hard-and-fast indicator of problems.
Obviously the alternator has less power available when the engine is idling, but this is why the usage is critical. If you're spending a lot of time boulevard cruising in hot weather, and the car has an electric fan then you are more likely to run into trouble than if you frequently travel hundreds of miles at high average speed in cool air.
Power rating of audio equipment does not necessesarily relate to the average power drawn. A 65A alternator will probably run ~65A, but amplifier power outputs are ill defined, and amplifier efficiencies vary widely.
65A at 14.8V is still nearly 1000 Watts. Depending on the automobile, alternator, ancillary equipment fit and how the charging regime operates this may be enough.
This said, if I had installed a load of power-hungry kit in my car and my alternator failed for whatever reason, I would take the opportunity to upgrade now rather than later 'cos in the absence of hard-and-fast information it sounds like a good bet and you might need the power in the future anyway.
w
wakibaki said:
fortunately that is worst case. which is engine idling at ~700rpm, all lights on (headlights and foglamps) A/C and stereo. drops to 12.1V at times when the compressor is on. (for the semi truck horns, you need those the way people are driving around here.... ) when the engine RPM goes to around 1500 and above, it jumps to about 13.2 volts. thinking of getting a smaller pulley...
There is no way to stress a properly designed alternator with any car sound system.
The output of an alternator is in form of current, not voltage. Only the regulator cares about voltage and tries to adjust current.
The magnitude of output current is controlled by the current allowed to flow through the field coil by the regulator. Thus, output current is under control and can't go above design limits.
Alternators fail because of aging and sometimes because of their low quality (they are not really intended to operate at their rated load during long periods at high temperartures).
The output of an alternator is in form of current, not voltage. Only the regulator cares about voltage and tries to adjust current.
The magnitude of output current is controlled by the current allowed to flow through the field coil by the regulator. Thus, output current is under control and can't go above design limits.
Alternators fail because of aging and sometimes because of their low quality (they are not really intended to operate at their rated load during long periods at high temperartures).
My wife owned a 98 SL1 for a while and while troubleshooting an intermittent start problem I noticed the wire going from the alternator to the battery terminal is very thin compared to the main battery cables. The cables coming off the battery are pretty big, maybe 4 awg. The wire coming off the alternator couldn't have been bigger than 12 awg. Not sure if your '01 is built in a similar way or not but its something to check. My problem turned out to be a very corroded wire going to the starter. Just for laughs I stripped off the insulation and the copper was turning blue a good 18 inches away!
The best thing that you can do is to not have the stereo come on automatically after you start your vehicle.
The alternater is engineered to be able to handle charging the battery immediately after starting.
If you ask it to give a whole bunch more extra amperes to power your stereo at the same time -then you will have to replace it often.
2 solutions are:
-Buy a bigger alternater or,
-Wait 3-5 min before turning on the stereo.
I run 4 pretty large amps on my truck and after prematurely paying $600 for a new alternater, (was unable to upgrade at the time) I decided to do the waiting thing and haven't killed any alternaters since. -If it does happen again, I will upgrade to a 200A one (now available).
The alternater is engineered to be able to handle charging the battery immediately after starting.
If you ask it to give a whole bunch more extra amperes to power your stereo at the same time -then you will have to replace it often.
2 solutions are:
-Buy a bigger alternater or,
-Wait 3-5 min before turning on the stereo.
I run 4 pretty large amps on my truck and after prematurely paying $600 for a new alternater, (was unable to upgrade at the time) I decided to do the waiting thing and haven't killed any alternaters since. -If it does happen again, I will upgrade to a 200A one (now available).
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