What is the best replacement for the 12V battery for a 2019 MDX sports hybrid?

 

hybrid uses a conventional FLA (flooded lead acid) battery rather than requiring a AGM. Interesting that you need a new battery after only 3 years. Don't have a brand recomendation.

 

I would go with OEM and find the best deal.

 

I never seem to get more than 3-4 years from Acura OEM batteries living in the southwest. My 06 TSX, 08 RDX, and 11 MDX batteries all crapped out just after the 3 year mark. I replace the OEM batteries with Interstate and always got the full 5-7 year warranty period/life advertised for that battery model. I put in the AGM battery in my 11 MDX because I also installed a dash cam. I've never had slow crank, warning lights, check charging system message, or issues starting if the car sat for weeks with interstate batteries. After +15 years on this and other Acura forums, the right choice for a battery replacement is anything other than OEM.

I took my 18 RLX hybrid in for an oil change this week and to double check an "U0104-00 ACC may not operate properly with brake system" message. The tech determined it was a bad OEM battery and replaced with the same under warranty. I'm still on my OEM battery for my 19 MDX hybrid with +26,000 miles. I will be looking to do a pre-emptive strike and replace my OEM battery late next year sometime (probably after the summer heat). Interstate only offers AGM batteries for the MDX hybrid on their website (which is my top choice anyways).

 

12V batteries are covered by the 4yr/50K mile warranty if they test bad. But if you don't want to put another questionable OEM battery in there, I have had luck with the batteries sold at Costco.

 

For the time being the battery is ok but I wanted to start researching the subject in case this winter takes a toll on the battery

 

I'm going to replace with an AGM battery when the time comes for my 19 MDX hybrid. I'm still not 100% sure how the 12v battery and EV battery works together or separately to power the accessories when parked, A/C and water pump in EV mode, restarts the motor when coming out of EV mode, powering the all the lights, remote start/keyless entry/push button start, etc... I've just noticed I only got a little over 30 mins of lunchtime radio time in my 11 MDX before I needed a jump with an OEM battery and +1 hr with an AGM battery without a drop in power.

AGM would be also good for extreme heat/cold, vibration, if have to take a lot of short trips because AGM charge faster, less terminal corrosion because of glass mat construction, or extended electrical demands like with a dashcam in park lot mode.

 

I've had 2 RLXs and now MDX. Have never gotten over 3 years on a battery

 

The charging profile for AGM batteries is different from that for conventional lead-acid batteries. Since the charging circuit for the hybrid MDX is designed to work with lead-acid batteries, there is a possibility that it may cause damage to the AGM battery if such is used instead.

 

Thanks for the heads up. I have to check into this and see how folks with the RLX hybrid are doing with battery replacements since 2014.

 

I have the scanguage for my 19MDX. I have one setting showing the EV battery pack charge/discharge rate and one showing the 12V battery voltage. From what I've observed the EV battery pack keeps the 12V battery charged and likely provides most/all the current needed to run all the 12V accessories whenever the car is in the "run" mode, even when the gas engine isn't running.

 

The unfortunate part is the EV battery doesn't trickle charge the 12v battery when the car is off. We ran into this with the wife's 18 RLX SH last winter during Covid when the car sat unused for over a week and AcuraLink "informed" us that it would no longer send status updates due to reduced battery charge.......... That would be an interesting feature to have added!

 

I had the same issue with both my hybrids from letting them sit too long between drives the first months into the shutdown. All kinds of error messages in Acura link. The solution for me was to drive both vehicles more often and run my errands/shopping further out instead of my local area. No error messages since after +15 months.

 

Make sure your key fob is far away from the car. It will constantly communicate with the car leading the battery drain. Dealer already replace 12V twice in last 2 years. My wife's desk is on opposite wall of the garage. She likes to put her key fob in her purse which sits on the desk. We were wondering why the battery keeps dying even though we drive her MDX quiet often, at least once or twice per week. I've asked her to move key fob to shelf in living room. So far battery seems fine. Cranks nice and strong every time.

 

the big difference is charging profiles between a FLA and AGM battery is that one must NEVER use an equalization cycle (applying close to15V) to the battery to equalize cells, while that is common practice on deep cycle FLA to extend life. However in a car there is NOT an equalization cycle from the charging system, and the starting FLA or AGM batteries are pretty interchangeable from a charging standpoint. The AGM can be cycled deeper than a typical FLA starting battery for more cycles before damage, so that's why they are often required for cars with start/stop technology.
For cars if AGM is specified IMHO don't go with a FLA replacement. If FLA is specified, it's fine to go with an AGM replacement. It will cost more and depending on your climate and use may or may not provide a longer life.

 

FWIW, dealer replaced 12V battery on our 2017 MDX Sport Hybrid with part# 31500-TZ7-AGM100M which I assume is a AGM battery. I've been using Mroinge MBC010 trickle charger which states it's good for all 12V lead-acid batteries, including flooded, GEL, AGM, VRLA, Deep-cycle and maintenance-free batteries. I've asked Service Advisor if it's okay to use trickle charger on the MDX-SH. He said do not use trickle charger due to all the fancy electronics in the car. Not sure if he's correct or just talking nonsense. To be on safe side, I've stopped using the trickle charger.

 

Just chiming in to say that after 6 years, my 2017 Acura MDX Sport Hybrid Advance finally needs a new battery. It has not died on me yet but a test says that it is due (had it tested because my 2014 RLX did just die). Dealer quoted me $350 which was ~$120 more than the RLX battery. Had no idea the MDX had such expensive battery tastes.

 

The OEM battery in my 2017 MDX Sport Hybrid was getting a bit weak, so I replaced it a couple of months ago with an Interstate H6(48) AGM battery from Costco. I paid $170 for it, so not too unreasonable.

 

Just wanted to show tha my 2018 sport hybrid also has agm battery. I was looking for a date sticker but didn’t find it. I wonder if it is OEM still considering this car only has 31k miles at the moment.

interestingly, I noticed a bunch of modules attached to the side of the battery. I don’t remember seeing that in my 14 MDX. I wonder if it is specific to sport hybrid or agm batteries.

anyone know how to tell if a battery is Acura supplied?

side note: I checked the 10mm nuts to the terminals and I was able to make a several revolutions before it became tight! I wonder if that was what’s causing all the random electrical gremlins.

examples include emissions system light/electric parking brake light that threw a p0420 code and disappeared after a longer drive; car automatically locks car within 5 seconds after unlocking car at random, in the mornings; blind spot monitoring in driver side was flashing one time instead of full solid and passenger side works sporadically unable to trust it; I’m still new to the car but noted engine still running when was expecting EV mode while in certain normal IDS mode presumably to charge the battery?)

 

So my sport hybrid been showing interesting symptoms first thing in the morning while the car gets parked outside overnight in the cold. I know these AGM batteries can be expensive so I decided to trickle charge it and I have not had the symptoms thus far. So I decided to wire in the trickle charger quick connect to keep it in tip top shape and also monitor the battery status through Bluetooth tracker app.

 

Not sure why Acura changed from AGM for the 17-18 MDX SH to Lead-Acid 12v for the 19-20 MDX SH? I figured it was A-OK to upgrade my 19 MDX SH to AGM because the 17-18 MDX SH came with that type of battery. I changed out my OEM lead-acid 12v on my 19 MDX SH at +53,000 miles with the Costco AGM H6 (48) back in Apr/24. No issues with the OEM 12v and I just wanted to do a preemptive strike after +5 years original battery.