Wash MDX yesterday and went to start it, got this crazy mess of lights flashing. I guess my battery is toasted. Battery is only 26 months old! Thank goodness I was parked at home and not got stranded somewhere in the woods. Very disappointing that this battery doesn't last very long. Finally got it to start and went straight to dealer to replace battery, all under warranty.

I use battery Tender to trickle charge my other cars. Does anyone know if I can trickle charge the MDX Sport Hybrid AGM battery?

 

since it's an AGM battery, your trickle charger MUST be able to trickle charge AGM's.

it's NO different than ANY other AGM battery.

 

What is AGM?

 

Absorbed Glass Mat

AGM is maintenance free, provides good electrical reliability and is lighter than the flooded lead-acid type. It stands up well to low temperatures and has a low self-discharge. The leading advantages are a charge that is up to five times faster than the flooded version, and the ability to deep cycle.

 

Thanks for the explanation.
Is the 12 V battery that feeds all the electronics AGM, or the battery that drives the rear wheels in the Hybrid AGM?

 

What trickle charger do you have?

 

The main 12V batttery to feeds all electronics

This one, it say it works with all type of batteries including AGM. Been using on my other cars for 2 years now without any issues. I'm afraid to use it on the Sport Hybrid since the main AGM battery is connected to other electronics. Don't want to mess with the on-board computer. Service advisor said not to use trickle charger on Sport Hybrid AGM battery.

 

Got MDX back, all good they replaced AGM battery under warranty. But damn they put on 500+ miles on my car. Isn't that excessive? Did the mechanic took it for a statewide joyride. I'm pissed🤬. Why the hell do they need to put on so many miles just to replace a battery? They did keep my car over the weekend. Looks like the mechanic took it home with him and went on a road trip or something.

 

sounds like a gripe to bring up with the service manager

 

that is unacceptable bordering on criminal act. it's the same as stealing something like $300 out of your pocket considering the IRS expense reimbursement rate per each mile is something like 60 cents....

 

which dealer is this? You should report this to https://dcba.lacounty.gov/ they actually do a pretty job of settling complaints with local businesses.
Please do post the name of the dealer and the service dept. manager's name.

 

I did call the Service Advisor. He told me he may have mistakenly took down the mileage wrong when checking in my car. In mileage show 26261, out was approx 26700. I didn't take a picture of mileage when I dropped it off, so I can't prove anything. Pretty sure I had a full tank of gas when dropped off, now it's 1/2 empty. And Trip computer show last trip in the low 10s MPG. So they must have drove the MDX very aggressively to get that low of MPG. He said they needed to disconnect battery to replace it so Trip Computer may not be accurate, seems reasonable. He also said they have reading from when they hook up my car to computer to read the code, he said it shows In mileage was aprox 26700. Again, it's his words. I don't know if I believe him. But I still have a feeling the mechanic took it home all weekend long for a road trip to Vegas or something.

I was very happy with the service given in all previous visits. Now not sure if I will come back to this dealer. Thomas Acura in Covina, CA.

 

EDIT: I believe the service adivsor is telling the truth. Based on my video above which I took before I dropped off the MDX, it shows 1/2 tank of gas and Trip A was 216.6 miles. Trip A now shows 230 miles and still 1/2 tank of gas. Seems accurate to me.
Sorry folks false alarm. Thomas Acura is all good with me.

 

put away the pitchforks folks

 

OK.

going back to the 12 volt battery issue, something doesn't sound right to me. You hybrid battery, when dumping off its energy (say, you went down a long hill), charges your 12 volt battery. In fact, the 12 volt battery doesn't work off of an alternator - there isn't one. In other words, it's like having a trickle charger hooked up to your 12 volt battery all the time. For example, my 12 volt battery is original and I have 100K miles on my car.

 

This is true, hence why they don't advise to use a trickle charger for the 12V AGM battery. I believe in my case, one of the cell in the 12V AGM battery failed. Thus leading to low voltage hence I could not start the car and it threw a bunch of error codes. Hope this 2nd battery will last a very long time. Nonetheless, I'm going to buy a portable charger to leave it in the MDX just in case this happens again while on a road-trip so we don't get stranded. So many systems depend on that 12V battery. I wonder why I didn't get any warnings the battery was bad before it catastrophically failed. Dealer load tested battery on last oil change visit too, it was all good back then. Not having a good feeling about all this.

 

Batteries can fail without warning. Nothing new there. In modern cars with all the battery-dependent systems, good idea to have both a set of jumper cables (Low Tech, no maintenance) and a jumper pack (Does require regular recharging), IMO.

Not sure how the Hybrid system works on your X, but if it has idle stop and uses only the AGM battery for restart, that may cause excessive wear on the battery due to greatly excessive starting cycles.

 

Yes, Idle Start/Stop does rely on the 12V AGM battery. Service Advisor mentioned same thing. On-board computer should be able to determine low voltage situation and send a warning. I got zero warning, just die out of the blue. Very fortunate I was home at the time.

 

Acura batteries (re-branded Interstate batteries which are made by Johnson Controls) are trash! We non-stop replace batteries. But as long as you have a warranty on the battery keep using it and keep getting it replaced for free lol. The inconvenience just sucks... When that leisure runs out, get yourself a good AGM battery made by East Penn Manufacturing like the Deka Intimidator or the Duralast Platinum. There's many others too, but those are more pricey.