Correct battery voltage levels?

[discojunkie76]

I've been having trouble with a rough Idle, and been told it could be electrical. The voltage level on the battery is roughly 13.7 volts at idle, however In gear it seems to drop slowly to about 12.7 volts, and the idle is really rough, and has been getting worse in the last few weeks or so, I use the 115v outlet in the car a lot, could this be an issue. This basically appears to be an alternator problem. However I'm new to the whole foreign car thing, And wondering if it might be my rice bearings or something. Also if I need to replace the alternator what's a good reasonable brand.

[Petrucci914]

Rice bearings? Give us the specs of your car. It could be a dirty throttle body and IACV valve. Just using the outlet in the car shouldn't make it idle that bad. If you had a large stereo system you could be draining the battery more than the alternator can charge.

[joatmon]

In August 04 you said you just picked up an 05 vibe, is it still under warranty?I would expect to see a battery voltage of about 12 - 12.5 V when not running, and somewhere up around 14 - 14.5 when it is running. THe AC inverter only puts out 100W, so the electrical system should be able to handle it no problem. I don't know what rice bearings are, but if the bearings in the alternator are going bad, then I would expect it to make noise, not lose ability to generate.

[keithvibe]

Don't quote me on this but I think what they ment was race... not rice bearings.

[jimincalif]

I seriously doubt it is the alternator. The voltage regulator controls the alternator output to hold about 13.8 volts, so your 13.7 measured is right in line.When you put the car in gear (assuming automatic) the RPMs probably drop. The alternator puts out less power at lower RPMs, not unusual for voltage to drop a bit when RPMs are under 800 or 900 (generally, I've never measured my Vibes battery voltage.) Since a fully charged 12v battery at rest would read about 12.5, your 12.7 shows the alternator is still putting out a few amps, enough to run the car electrics.

[discojunkie76]

The rice bearing thing was a joke.... asian import car made of rice, rice burner, rice bearings, rice pads etc.etc

[discojunkie76]

all stock (base model) except drop in k&n and its just been cleaned. What is the best way to clean the TB? since its all electric.

[Sublimewind]

Best thing you can do for your car electrically is A. Clean up ALL of the motor grounds, remove them, clean off the paint, apply dielectric grease and re-install. (cleaning up any ground you find isn't a bad idea)B. Doing a "Big 3" or adding to the ground from the alt to the batt, batt to the car and from the motor to the car. The improvement "can" be dramatic. Factory cars electrical system are "just enough" to get the car by, using their standards and the standards AREN'T in terms of performance.... PRICE is the standard auto manufactures use to make decisions on things like this.... One strand of wire in a electrical system can be worth MILLIONS over the course of that wiring harness being used in a model line.... Many buy grounding kits... that's great, a few pieces of wire with terminals, but a little time and work and they can easily be made and installed for half the price... Something to consider