New to me 2008 RDX.

I am liking the little SUV (gave the 2009 MDX to my daughter for now), but I am slowly working out quirks.

One of those being the "Check Charging System" when I first start it in the morning. It only last 1-3 minutes and then clicks off. No codes and the battery test good. When the chime is on, it shows around 11.2 volts and when it kicks off it's back up to 14ish volts. Never struggles to start. Battery is only a couple months old. I have cleaned battery cables and used terminal grease. Also disconnected the HFL (this was an issue on the MDX so was well versed it in being a possible culprit).

The belt and tensioner seem to be within spec too.

I am guessing it's an alternator/voltage regulator, but don't really want to throwing $120 bucks and an hour or two of my time to replace it if it's not the issue.

Anyone else battle something similar?

 

I'm not a fan of replacing parts too soon but in this case where you've some good checking on other possible causes it does appear your alternator is on its way out and it is a part that can leave you stranded when it does fail. It will fail at night on a long drive while it's raining or snowing and you're in the middle of nowhere.
Alternators don't last forever, they do contain parts that wear out (brushes) so it might not be a bad idea to replace it now before it completely fails. Your original alternator probably has high miles on it and has lasted a long time already. I'd recommend a Denso remanufactured alternator, I purchased a lower price remanufactured one and it worked but made a whining noise so returned it and went with the Denso.

 

What is the voltage during cranking. is 11.2V the lowest it goes or is that immediately after the car fire and starts up. What are the battery specifications.

When my GF's alternator packed up it just dropped out all at once and died.

When my alternator in my old car had a regulator issue, the voltage output was 12.8 during running and it was not enough to charge the battery.

The alternator has a sensing wire, maybe that has corrosion?

Does it make any odd sounds?

 

Doesn't make any odd sounds that I can hear (new to me car though, maybe it is and I just don't notice it).

I took the sensing wire off but didn't see any corrosion and could not for the life of me find my terminal grease, guess I'll have make a stop today.

The battery was in the car when I bought it and looks to be about as budget as you can get. CCA is not listed on the top and I haven't pulled it out yet. Shows 600plus CCA when load tested though, so I don't think that's the issue.

 

I cleaned the terminal and larger wire at the alternator with no luck. Same issue

I also noticed it pops up at startup in the middle of the day when it's been raining heavily too. That's interesting as it doesn't do it in the middle of the day when it's dry out.

 

Might be an issue with the belt tensioner or the belt itself

 

I like to reply to my own threads when I figure out the fix so anyone in the future can see it:

It was the alternator. Not sure why it wouldn't charge for the first few mins of driving and then "click on" - but it got progressively worse. It started to last 10 mins or so of not charging and when driving short trips at night (with lights on) the volt meter would start dropping close to 10v.

Just so everyone knows, these cars damn near become inoperable when voltage is that low. Check engine, check VSC, check SHAWD all pop up. The transmission starts to act like the torque converter is toasted. It was not a good experience to limp it home. Replaced the alternator out of desperation (ordered from rockauto, cheaper than Amazon and locally), and it works as it should now. The alternator was a piece of cake, the belt SUCKED though. My fat hands can't reach in there well and it popped off the crank pulley. The only way to get it back on was to remove the passenger tire and reset the belt that way.