andysinnh

A little less than 2 years ago the wife's 18 RLX (at 15.5k miles) had its 12v battery die - couldn't start the car, and had been giving AcuraLink "low power" warnings after sitting for several days. Dealer replaced the battery under warranty, and all was good. Fast forward to the past week, when I got another "AcuraLink low power" warning after the car sat for about 4 days. Took the car out, ran it quite a bit, and things were back to normal (and AcuraLink was happy).

Today I got the warning today from AcuraLink again, and the car had been sitting for about 5 days this time. Before I started it back up, I hooked it up to my battery charger/analyzer, and found the voltage to be 12.2 volts, and a 40 percent charge rating. I put the charger in "trickle" mode and the battery took the charge and slowly started to charge back up. I didn't start it yet to get a full charge, but I'm pretty sure it'll behave again.

But my question is this - am I seeing signs I just need to drive the car more - or is it a sign the battery is on its way out? I'd rather not get to the point where it dies fully again. I realize we don't use it a lot, and maybe our driving behavior is making the battery lose its ability to hold a charge. She's only put about 4k miles on the car in the past 2 years (still hasn't hit 20k on the odometer), so it doesn't get used a lot - but it does get used.

thoughts?

thx - andy

hondamore

Unfortunately, the parasitic loss to the 12V battery when parked is great enough that if you don't drive every day or every second day, you should probably routinely use a trickle charger to maintain your battery. Regular partial discharging of the lead acid battery will eventually cause weakness and eventual failure meaning that a battery that should last 5-8 years might be toast after 2 or 3 years.

I've had similar issues with my 2014 RLX Sport Hybrid (currently sitting at around 28000 KM or 17500 miles) which sits parked in our garage much of the time. After my second 12V battery replacement during the pandemic, I finally smartened up and began to routinely connect to a battery charger every time I park the car in our garage. Alas, 5 years later and I haven't had an issue (knock wood). It is a pain in the ass and you have to be very diligent in connecting AND disconnecting the charger, but my own experience suggests that it is worth the trouble for cars that are driven infrequently. FYI, the battery charger that I chose is the NOCO Genius 10.

You could also look into deep cycle batteries that are designed to be discharged to a lower lever routinely without negatively affecting the lifespan of the battery. I've read good and bad reviews on these, so due diligence is required before forking out the big bucks for a deep cycle 12V.

Good luck with whatever route you choose for your wife's car.

kareshi

4-5 days should be okay. but given your low mileage, does the car go more on short distance driving? are you able to see if it gets better if there're some highway driving?

DanL07RL

I have to gently disagree. So, you're telling me I can't expect to drive my car to an airport parking lot and leave it for a week or more for it to start!!??

mrgold35

I had my 12v battery fail in 2021 and replaced under warranty on my 18 RLX Sport Hybrid. Same issue of being stuck at home during the pandemic, less than 5000 miles per year, the RLX (and my MDX SH) giving Acuralink low power warnings, and I was getting warnings messages on the RLX navi screen (U0104-00 ACC not working & U1100 Gauge control module lost of commo). Both vehicles gave the Acuralink low power warnings with same sitting time; but, the OEM battery failed with the RLX. I used my battery charger more and drove more frequently/longer during the lockdown to help prevent this issue for both hybrids. I've been fine with the RLX since with the replacement OEM battery and back to +/- 10,0000 miles per year schedule.

Ended up swapping out my 19 MDX SH +5 year old OEM battery with an AGM from Costco as a preventive strike. I might do the same for the RLX sometime in 2025 for piece of mind.

hondamore

The issue is not leaving your car at the airport for a week but routinely not driving for several days EVERY WEEK. With long-term, repeated periods of slow battery drain, the lead acid battery will deteriorate and after a few years weaken enough to cause issues. As other have mentioned, the damage to the battery from infrequent driving can be exacerbated by frequent short trips that don't give the alternator an opportunity to fully charge the battery.

I'm sorry if my earlier post was not clear on this point. My comment were related to those who only drive their car maybe once a week and frequently don't drive for a couple of weeks or those who maybe drive 10-20 miles a week. In these situations, I recommend a battery charger be used routinely to maintain a "healthy" charge in the battery.

andysinnh

Thanks for everyone's input. I'm pretty sure that her driving habits are the ultimate cause of this issue. So far, driving it every 2-3 days is seeming to keep the battery happy, so for now that's what we'll do. I'm just wondering whether the hybrid has a different 12v requirement and/or charging method than a typical non-hybrid? I ask because if I let my 19 MDX sit for the same number of days, I never get a low-power notification and the battery seems happier? Anyway, we move forward. Wife loves the car. With only 19.5k miles on the odometer, and it nearly paid off, you can't find anything to even closely replace it. :-)

andy

mrgold35

I'm out of town in my 19 MDX SH since July 13th and just got a Acuralink email notification of "Loss Communications" with the 18 RLX SH yesterday (7/18/24). That is usually my first warning in Acuralink of 12v low voltage I would get during the lockdown. We won't be back home until Aug 4th at the earliest and hopefully the RLX will start.

kareshi

Please keep us posted

jdpdata

Whenever we're out of town for extended amount of time (7 days+), I put the MDX on trickle charger. Never any issues with Christmas lights on dash anymore after I do that. You just have to accept if you don't drive it much, 12V battery will die prematurely if you don't keep on charger. Maybe it has parasitic drain somewhere in the electrical system. My RLX never have any battery issues even when not driven for weeks at a time.

mrgold35

The RLX started no problem after sitting for a little under a month. I double-checked the 12v battery charge and it was at 51% (12v battery replaced under warranty in 2021). I placed on the charger and Acuralink starting working again.