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depends on how much load you are putting on the electrical system. it is normal for the rpms to dip at idle with an electrical load such as the windows...
 

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Theres nothing odd about that. The battery that is stock in out cars sucks... have you ever tried to jump start anyone with it. doesnt have shit for cranking amps. of the 3 times ive tried to jump start someone im yet to have it work.
 

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Theres nothing odd about that. The battery that is stock in out cars sucks... have you ever tried to jump start anyone with it. doesnt have shit for cranking amps. of the 3 times ive tried to jump start someone im yet to have it work.
Just a friendly word of advice... DO NOT JUMP START with the RSX. There is potential for serious electrical failures if something goes wrong... electrical spikes, battery being boosted is shorted, etc...
 

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Sorry to hijack a little bit, but my voltage problems might help relate to your problems.

I think I may be having a problem with my alternator. I have a radar detector that displays the car’s voltage, this is what I’m getting my voltage numbers from (I have verified with a multimeter as well.) The car is an 2006 RSX Type-S with 9k miles.

Here is what it doing. After starting the car and idling I see 14.2-14.4v (with or without accessories on). Then after driving a bit I can see the voltage drop to 12.8-12.9. After the voltage goes low like that it stays low at idle and under light engine load, but if I rev to above 3.4-3.5k rmps I see the voltage rise to 14.2-14.4. When the car is off the battery reads 13-13.1v

I just took it to the dealership, and they say everything tested fine. Is it normal to see voltages around 12.8-12.9 while the car is started? I seem to think it is not ok.

Cliffs:
1. Idle voltage 14.2-14.4v.
2. After driving a bit it goes to 12.8-12.9.
3. Dealership says everything tests fine.

Thanks for any help!
 

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snawdjj: Fluctuation is typical of all cars. Since you alternator never spins at the exact same rate, nor does it ever have the same draw. To put it simply - the alternator adjusts it's field on the fly to supply the correct amount of current (voltage and amperage). This is not instantaneous either. (Which subs/amps/capacitors go hand in hand). As long as your voltage is not dropping below 12.1v you should be perfectly fine. It will spike to 14v for the first few minutes of driving as it recharges your battery from the last crank (batteries need 14v to charge).

speeddemon619:
Your battery is dying. The battery acts as a bit of an electrical buffer (like a slow capacitor) while the alternator catches up. A sign of this is your headlights dimmer a LOT when you roll you windows down. A small flicker in their intensity is typical, but not a major difference. Take your car for a drive - normal drive, come back and check the voltage across your battery with the car off. If it's around 11 or lower, replace it.
 

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Oh yeah, one more thing - from my experience - most alternators either work entirely as they should, or don't work at all. Once one little diode blows or coil shorts - the whole thing stops working. I do believe you'll get a battery warning light on your dash when the alternator blows.
 

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skreak: Thanks for the reply. After picking my car up from the dealership and watching them run the tests, I’m thinking it normal to see voltage drop like that. It’s weird though, I’ve never seen any other car voltage swing like I see on mine. What you are saying makes sense, and I’ve not seen it get below 12.8v. I’m going to do some data logging with an OBDII carchip just in case I need to have some evidence of what it is doing. But in all I think it is fine.

Hope my episode can help someone else in the future. I’ll post any updates if something messes up.
 
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