2017 is approx 3.5 years old now with around 55000miles.

I haven't been driving it much and on occasion it has a slow start and one day was completely dead until I boosted it.

Now thing is I do have a power sucking power magic pro to enable my dashcam parking mode.

Anyways I took a multimeter reading today after the rdx sat for around 16hrs. I had disconnected the power magic pro the night before as well.

So 12.33V reading at cold...is it time to replace it? Started up fine today. It was 14.37V when running.

 

Looks good from what you are showing us. However, a volt meter does not always tell the who story when it comes to the battery. A lot of battery testers will perform some type of load testing to help provide a more accurate assessment of your battery. The battery should read in the 12v range when the engine is off, and around 14v when the engine is running. That is the poor mans test to make sure the alternator is running. Also if you don't run the car a lot, put a trickle charger on it once a week to help keep it charged. Best of luck.

 

Even an almost dead battery will read in the 12 volt range when it is not under load. A mechanic will usually have a "load tester" which is connected across the battery terminals, in order to draw current from the battery (i.e. put it under load). The load tester will have a meter which shows if the battery is good or bad. Many shops that sell car parts will load test your battery for free.

To do this in your own driveway, you can uses the starter to place a load on the battery. Monitor the battery voltage when you attempt to start the car. As a rule of thumb, the voltage should not drop below 9.5 volts. The actual voltage varies slightly as the battery temperature changes.

If the engine starts too quickly to get a reading, you can also "load" the battery by turning on as many accessories as you can, For example the headlights, HVAC blower, rear window defogger, seat heaters, etc.

As you already know, you should obtain a voltage of 13.8 volts or higher (depending on temperature) when the engine is running, if your alternator is working properly.

 

Actually, the Acura' have Dual Mode charging systems, so a 12.5V reading with engine running can occur. See the following:

For many years Honda and Acura have utilized a dual mode charging system to increase fuel efficiency and to
decrease the drag on the engine when starting. The two modes can accomplish as much as 10% load reduction on the
engine by allowing the Electric Control Module (ECM) to determine charging rates based on information gathered
from an Electric Load Detector (ELD) and various other sensors.
During heavy electrical or mechanical loads (i.e., if the AC clutch
is engaged), the ECM will set the charging voltage to 14.4-14.9V
(high output mode); during startup and light electrical load
conditions, the ECM will set the charging voltage to 12.4-12.9V
(low output mode). In the latter case this anomaly might cause a
technician to try to diagnose a low charge problem, although it is
normal to have 12.5-12.7 charging voltage when the parameters
are met.

This might confuse most technicians because it takes more than
12.6 volts to charge a battery. However, while in the low output
mode, the alternator is not actually “charging” the battery but it is
just holding the battery voltage at 12.5-12.7 volts. The main draw
on the battery occurs during startup and after the battery has been
charged there is no need to keep the voltage higher than what the
vehicle needs. After the battery has been charged most of the
current is drawn from the alternator as illustrated in figure 1.

Thus, this system increases efficiency by charging the battery
only when needed.

 

Under those circumstances, depending on the temperature/ season, it would ensure that you don't freeze yer nuts off waiting for AAA. Battery tender would be good if suitable. Otherwise gamble it for the next couple years? Load test should shed some light...

Hitting the 4-5 year mark on mine, gave me some tough starts last winter Sub zero temps, head lights would dim until revved up, so replacing before this winter to not be stranded after numerous short shopping trips

Considering $150cdn for an average wet cell, 200 for a Costco Energizer agm, 300+ for a questionable red/ yellow top optima and 400+ for a pure lead Odyssey or Northstar, anyone have experience with the agms? Worth the hoopla for longer life, phantom draws, quick charging and cold starts? Or better off skimming 98 dollar Wal-Mart specials?

 

I am new to Acura-I came from Mercedes. My Mercs used AGM batteries. I replaced them simply for peace of mind after 8 years on one and 10 on the other, although they were starting the cars and charging up just fine.

 

The battery in my 2016 lasted 3 years and 4 months which is quite good considering most of that time was spent in Phoenix. Had it replaced last year. I don't know about Canada, but in the US the battery is covered under the 4 year bumper-to-bumper warranty so the replacement was free from the dealer.

 

And that is what this sensor does on the Acura battery...


Real load testers are cheap and can be had at Harbor Freight for about $50. Run the load to 1/2 of the battery's CCA and it should maintain 10.5V for at least 15 seconds (the Harbor Freight unit is not cooled, so that is the limitation for the time). MidTronics testers for example do battery tests but they are a conductance tester and do not provide accurate numbers having tested them.

I got 16 and 15 years out of the last two batteries, so they last if the charging system is up to snuff and you do not let them sulfate.

 

I've heard the Phoenix heat melts traffic signs, def killer on the batts otherwise. Up here rarely hits 95f few months of the year, but can plunge below -30 five months of the year. Extremes to be had.

Good to know your Merc experience, just picked up the Energizer agm from Costco today, 5 year warranty and good value price, so we'll see. Will post review in 5 + years or if things blow up before then y'all be the first to know 🕺