This is definitely an alternator, right?

2006 Acura TSX. 

Driving today the "Check Charging System" light came on. Monitored the voltage while driving, continued to go down and down from over 11.5 on idle and 12.5 on acceleration; by the end of my trip (15 miles or so of mixed highway/city), it was struggling to get to 10 under acceleration--I was losing my dash and shifts were getting very rough at that point as well. Battery is new enough that I'm 90% sure it isn't the battery. 

It isn't currently throwing any codes, but that is because it lost almost all power while pulling it into the driveway and likely wiped them. I think that the "BRAKE" light, air bag light, and a couple others were on at some point too. 

Money is really tight right now, so I'd really like to not be chasing problems. This is something that I'd normally handle by picking up some more work and dropping it off at the mechanic, but that isn't an option right now--I'll have to do this myself.

meant to put this in GRM. Oops.

Definitive test:  Put voltmeter across battery.  Measure voltage with car off.  Start car.  Measure voltage with car running.  Should be greater than with off.  If not, your alternator or voltage regulator (could be one unit) is dead.

Moved. Sounds like classic alternator issues to me. 

Alternator and regulator are all in one (I'm 99% certain) so pull it off and take it in to a parts store to have them throw it in their tester. 

Alternator for a TSX is cheap. Maybe 90-100$ new.

Guys are right, check voltage at battery with the engine on and off to see if it is charging. Make sure you give it a bit of a rev when you start it in case the alternator is coming on slower then normal or does not change at IDLE.

Is the belt really loose?  If the alternator is truly dead, the voltage shouldn't be going higher under acceleration.  Might have burned a diode and gotten weak, but it should be howling if thats the case.

Does sound like an alternator. Have had the alternator in SWMBO's car go out a couple months ago. While driving cross country, not fun. Daughter had one go out a month or so ago. All had same symptoms as you have. Will run the car until battery power runs out, losing systems one by one. Never got any howling.

remember  this is 6 cells with 2.2 volts ea. A Fully Charged Battery is 13.2 V not 12 so if the meter reads 11 v or less after charging the Batt. has at least 1 bad cell. as said once you are off idle if the voltage rises and falls you could have just a loose belt. but when charging, an alt. will put out 14 V and the meter should see this.

GTXVette said:

remember  this is 6 cells with 2.2 volts ea. A Fully Charged Battery is 13.2 V not 12 so if the meter reads 11 v or less after charging the Batt. has at least 1 bad cell. as said once you are off idle if the voltage rises and falls you could have just a loose belt. but when charging, an alt. will put out 14 V and the meter should see this.

I knew some of this, but not why. Thank you.

Who else was reading the title of this post and thinking of these most unfortunate tattoos?

Wow those tattoos make zero sense. 

Luckily the problem does and it sure sounds like the problem is the same thing that apparently makes a great tattoo 

I just replaced the alternator in the Vibe which experienced exactly those symptoms. It's almost definitely the alternator. RockAuto has the remanned Remy's for 82 dollars (107.79 without core) for the TSX.

My vote is alternator.

Those tattoos are the "current" style.

They certainly are shocking, aren't they?

how amped up do you have to be to get a tattoo like that?

In reply to mad_machine :

Ohm my, watt a collection of tats.

Cells are 2.1, a fully charged car battery is 12.6. 

Regulators don't really exist as a 'part' anymore, the ECM usually PWMs the field coil circuit. If this was broke you wouldn't have voltage changing with rpm so that's likely not an issue.

It's almost certainly an alternator. 

A common failure point on high mileage units is the brushes.   The get worn to the point they lose contact with the slip rings.

It's possible that this car has a smart alternator.  Which is really why you should do Dr Hess's stuff.  

A smart alternator will only charge when it thinks it needs to.

There is a whole lot of things that can be wrong with a charging system besides an alternator, but most people don't like to hear about it because it just muddies the waters of their self-certainty.  Voltage drop in the charge  wire? Voltage drop in the ground circuit (i.e. through the case, mounting points, bracket to engine block, where does the main ground wire bolt, etc)? Continuity in the field winding (includes those brushes mentioned)? Fused power to field? Continuity from ground side of field circuit back to PCM? PCM voltage sense operating correctly? blah blah blah. I think it's an alternator in this case. If not, you will have to get familiar with a multimeter. 

Ram just went mild hybrid on all their 1500 trucks if i remember correctly. One of the nice things about replacing the starter and alternator with brushless motor/generators is that they pretty much never fail. Put them inside the transmission (like Prius et al) and you also get rid of EVERY belt-drive related problem. No belt noise, no compressor pulley bearing (or clutch), no idler pulleys, no alternators with their litany of failure points, no tensioner pulleys, certainly less harmonic damper failures, etc etc. Steering is electric.. The whole belt drive is basically obsolete. 

Alternator tattoo...is that a way of saying you swing both ways ("alternate")?

GameboyRMH said:

Alternator tattoo...is that a way of saying you swing both ways ("alternate")?

Apparently it for tattoo artists and tattoo receivers who don't know what a turbo looks like.  Strange.

In reply to alfadriver :

Which is always.