I have a ‘19 EX-L w/ 55k mi (DoM 06/19) recently bought CPO. Near as I can tell, original battery. I routinely see voltages 12.2 shortly after a drive and it takes a while to charge on my 6Ahr max charger. No issues starting.

I figured it’s a function of the lights staying on after engine off and seat motor and it’s a 70 Ah (FLA) battery so it has good capacity even at 12.2V.

Charge it full and let it rest overnight w/o activating any electronics ( keep key away too ), then measure battV. Should be 12.6-12.7, then it’s probably an ok battery.


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I have a ‘19 EX-L w/ 55k mi (DoM 06/19) recently bought CPO. Near as I can tell, original battery. I routinely see voltages 12.2 shortly after a drive and it takes a while to charge on my 6Ahr max charger. No issues starting.

I figured it’s a function of the lights staying on after engine off and seat motor and it’s a 70 Ah (FLA) battery so it has good capacity even at 12.2V.

Charge it full and let it rest overnight w/o activating any electronics ( keep key away too ), then measure battV. Should be 12.6-12.7, then it’s probably an ok battery.


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Let me test more... the day before, I had it charged up with automatic agm charger at night. So it shut off after it's done. But by the time I check it in the morning, the voltage drop back to 12.3v. it was cold that night (in the teens).

Btw, I think 12.2v is not a reliable voltage to always start the car in the cold. I am especially concerned to drive to ski trip with that kind of battery voltage. Being literally high and dry.

 

I bought the car back in 2018. A month back, I couldn't start my car with the battery came w/ the SUV on a cold day. voltage read between 12.1-12.3v. Then I got the battery replaced via in-warranty service. Today I check the battery voltage without starting the car (today is cold, 22F) before heading out (I dont want to be stucked outside at sub-freezing temp), its reading 12.3v.

Those voltages are way too low to reliably start your vehicle. Get the battery load tested as well as the charging system.

 

I agree, the voltage is below reliable range. thus the concern. The battery is just replaced a month back by dealer,and I have agm battery charger. I charge it when I see it low. But it's a hassle.

 

I'll link to my post in a different thread. My '19 EX-L with regular flooded battery is at dealer now trying to get diagnosed. Brand new battery with 12.7V after 20 minutes and 2-3 starts was low again at 12.3V.

I don't know how much the happy electronics of load sensing and variable output alternators thrills me to save fuel. Checking a running vehicle and finding 12.?V tells me alternator not working. Then you turn headlights or defroster on and it goes to 14.2V. So if you want to charge battery while driving you need something to draw more power unlike old days.

 

Yeah Honda's charging algorithm is stupid. It causes a lot of premature battery death. No idea why Honda doesn't change it. My wife works at a car auction and they constantly have to jump the Hondas and Acuras. A firend who worked at O'rielys told me the newest batteries they replaced were almost always in Hondas. GM batteries will be 8 years old fine Honda 2 year old battery dead form under charging.

 

Undercharging with an AGM battery is often a driver issue not an algorithm problem. AGM batteries charge faster than flood acid batteries, however they have a narrower charging range. If you don't keep an AGM battery's charge up high enough then the battery can easily degrade.

A vehicles alternator is not designed to charge the battery, it is designed to maintain a full charged battery at a peak charge. Driving habits have much to do with battery drain. Short little trips with lots of stops and starts can easily drain any battery.

One easy way to help minimize the issue to not buy a vehicle with all of the electronic bells and whistles, if you do not drive it enough, far enough to keep the battery in a peak condition. Without all of the electronic bells and whistles, you don't need an AGM battery in the vehicle.

My preferred method to keep my 2020 Touring's battery charged is to once a month go for a nice long, 1 hour minimum, drive at highway speeds. It still registers 12.8 volts after it has set overnight and is getting topped off with a 14.3/14.4 volt charge.

I use this simple device to monitor the batteries State of Charge. Under $20, and doubles as a USBc and a USBA port. The SoC is especially important when it comes to AGM batteries.

A fully charged AGM battery – 100% SoC – should read somewhere from 12.7V to 13.0V without load. A half-full unit, 50% SoC, should be around 12.1V to 12.3V, i.e. slightly above nominal voltage. A practically flat AGM battery at 10% SoC reads 11.7V to 11.9V without load.

 

Undercharging with an AGM battery is often a driver issue not an algorithm problem. AGM batteries charge faster than flood acid batteries, however they have a narrower charging range. If you don't keep an AGM battery's charge up high enough then the battery can easily degrade.

A vehicles alternator is not designed to charge the battery, it is designed to maintain a full charged battery at a peak charge. Driving habits have much to do with battery drain. Short little trips with lots of stops and starts can easily drain any battery.

One easy way to help minimize the issue to not buy a vehicle with all of the electronic bells and whistles, if you do not drive it enough, far enough to keep the battery in a peak condition. Without all of the electronic bells and whistles, you don't need an AGM battery in the vehicle.

My preferred method to keep my 2020 Touring's battery charged is to once a month go for a nice long, 1 hour minimum, drive at highway speeds. It still registers 12.8 volts after it has set overnight and is getting topped off with a 14.3/14.4 volt charge.

I use this simple device to monitor the batteries State of Charge. Under $20, and doubles as a USBc and a USBA port. The SoC is especially important when it comes to AGM batteries.

A fully charged AGM battery – 100% SoC – should read somewhere from 12.7V to 13.0V without load. A half-full unit, 50% SoC, should be around 12.1V to 12.3V, i.e. slightly above nominal voltage.
A practically flat AGM battery at 10% SoC reads 11.7V to 11.9V without load.

Thanks for pointing out, the "monitoring device" would help, so i dont need to pop my hood everyday to check...

 

In my experience Honda's batteries are garbage anyway. After going through 4 OEM batteries in 2 years with our '17 Elite we've been using the Interstate AGM battery from Costco with absolutely no issues.

 

I'll put same reply in a couple battery threads for other searches in futures by others.

So the dealer said Pilot was all fixed and the software update solved the problem and they charged by 5 day old battery to make sure no issues. Me- in my head "OK, Yeah right but I'll give the benefit of doubt" "kind of glad I bought that Honda Care from Hyannis".

While it's sitting in the service lane for pick up running I shut it off, foot off brake, turn ignition on, low battery warning. I walk back to advisor nicely smiling and say it's not fixed. They come out, confirm and take it back to the shop. They then came back after 15 minutes and say that they reset the battery sensor (not sure how they do that) AND that they ordered a new battery sensor, come back Saturday for quick replacement but the message should be gone and stay off but keep them updated. I don't know if better to let wife drive for the short trip and monitor or my longer work trip and monitor. It will wind up with her so that is probably best way.

I got home 10 minutes later and tried same scenario and no warning lights. Do capacitance test and I'm 12.8V and 750 CCA and 14.2V when running so good at this point. I guess the software update wasn't the answer maybe ? Stay tuned....

In the meantime just making sure the GooLoo portable jump pack is topped off and ordered some of Daltongang's USB charger with voltmeter to keep an easier eye on it. I need some of the rocker switch mount ones for the other cars where my phones are plugged in.

 

So latest updates- I let the truck sit after wife used it for work on Friday (start, 2 miles to work, sat all day, start, 2 miles home, sat all night) I checked battery with my my capacitance tester and my DVM. I'm at 12.18V and 769 CCA I was about 25 degrees over night. I plugged in Daltongang's recommended monitor and it shows 12.2V. Started car and all went to 14.2V and was 14.2V for the 10 minute ride to dealer. Keep in mind that the battery was 12.7V when new one week ago. Honda charged it and gave it back at 12.8V on Thursday after they charged it.

I went back to dealer and they replaced the battery sensor with the new one. It was covered but I think ONLY because I have the HondaCare 5/120 (adds 5 years to original warranty but still only 120k).

No low battery warning lights are on currently. I'm not used to seeing voltage that low. ESPCIALLY on 1 week old battery that was 12.7V.

Watching the car charger is interesting. I'll need to drive the truck more to work to see if it charges on it's own before putting back on the charger or bringing it back. If you drive under normal around town conditions, volts show battery voltage (12.2V) if you turn on the headlights or rear defroster it jumps up to charging (14.2V). if you take your foot off throttle so coast for upcoming lights/stop signs it slowly ramps up to full charge from 12.2V to 14.2V. If you step on brake lightly it jumps to 14.2V. I did not try it yet with a higher fan speed or A/C.

Side note on Daltongang's USB charger with voltmeter in my Accord. Driving to work at night, headlights on, 14.2V. Battery at 12.6v after sitting all night. Driving home in the morning 25 degrees, no fan on for climate, no headlights, just radio. 14.2V for the entire drive, light throttle 65mph highway and 40mph around town.

 

And more for monitor. Sitting at idle charging at 14.2V. Sitting at stop light or anywhere in drive 12.2V. Driving still 12.2V. Turn on climate control to high fan and both seat heaters to high still just 12.2V? Turn steering wheel at light it drops to 11.8V. Turn headlights or rear defroster on and you get 14.2V.

I have a 1.5hr drive each way to my family later. I'll monitor.

If anyone else gets a plug in or other voltage monitoring, report back what you find.

 

Sounds like the readings are normal. I would estimate that when you started the vehicle before the trip the charging rate was higher for a short period, until the battery had been topped back up. Once that state is reached then the charging rate would be reduced to just maintain the battery. If you turn on other accessories, especially high draw accessories then the ECM is going to adjust the alternator output to keep the battery topped off at the new, higher draw level.

The vehicle doesn't run on the alternator, the vehicle runs on the battery, the alternator keeps replacing the energy that is lost from the battery. You could in theory/and actual practice, run a vehicle without a battery once it is started, but the alternator does not put out a clean, steady source of electricity. These spiked could damage electrical components in the vehicle. The battery can handle these spikes that the alternator provides while maintaining a steady supply of electricity to the vehicle.

 

No higher charging rate showing from start up at 3pm except when slowing/coasting for the trip up and that was minimal. Maybe I'm too old school but 12.2V to me isn't fully charged or topped off. The capacitance battery testers on that show good/OK for CCA'a but also say "recharge".

I would consider both front seat heaters on high and climate control fan high (front and rear) to be a pretty high draw but the 12.2V never changed when I tested that for a short time. Alternator and ECU are probably happy there and it adjusted to just maintain that. I think it needs a reflash to 12.7V at least "normal".

Old school days when I had higher output halogen headlights, fog lights, driving lights and some amps for stereo I had to get high output alternators to maintain. First sign after longer mountain drives at night was "hey, what happened to the BASS?" but that was also cold winter, snowing so wipers, fan, A/C (defrost) and rear defrost on at the same time. Nothing was LED, low power.

 

Wanted to add in my recent experience:

I have a 2019 Touring with 30k miles, 28 months since purchased new. 3 weeks ago I took it to the dealer for the regular oil change. Ironically on the multi point inspection sheet everything was checked as good except battery, with was not checked as good or bad. The service advisor and I joked that this must be a simple error given young age and type of use (driven frequently 20 - 40 min trips mixed with longer 1 hr+ trips several times/ mo).
Fast forward 2 weeks and after a 20 min trip I turned the car off but left the radio on for about 15 min. When I opened the door to exit I saw what I thought was a brief battery warning. I immediately started the car with no problem and no return of a warning light. Turned the car off again after 30 sec and left the radio on sitting there for another 2-3 min with no issues. Car started fine an hour later when I returned from store to go home.
No additional signs of low battery or warning lights during normal driving next couple of days until one afternoon after a 20 min drive at highway speeds I reached stop and go city traffic. Car was performing auto on-off ignition as designed for about 3-4 minutes, (approx 3 red lights) and then all of the sudden the low battery warning flashed for a second or 2, the auto ignition tried to start the car and instead it just completely died. I tried to start it again manually, but nothing. Radio and Nav were on, and I was able to engage flashers. But it would not start.
I sat there with the car completely off for about 2 minutes and waited for all of the people honking to go around me while I started thinking about who to call for a tow (I was in a middle lane of a 4 lane downtown one way street with traffic rushing by except when the light turned red). After the 2 minutes I tried again and it started right up. I immediately turned off the auto start/ stop and continued to my appointment with no issues. I did park the vehicle in a position ready for it to be towed when I finished my appointment 2 hours later. Luckily it started right up again no issues, no warning lights, and no problems for the 30 min drive home (with the auto start/ stop disabled).
Next morning it started fine and I took it to back the dealer. After diagnosis they replaced the battery at no cost (other than my 2 hours at the dealer). When I inquired if this was normal and why there was no true warning light the response was "2 - 3 years is about right and who knows about the warnings with these crazy new computers"

 

ok, looks like quite a bit of people are aware of the low voltage AGM battery. I started using cigarette lighter battery voltage monitoring after suggestion from previous comments, this is my observation:

Observation 1: Usually, immediately after starting Pilot, it would read 14.2v (charging voltage). Then after some driving, it fluctuates between ~12.2-13.6v (this is actually normal, because the battery is not being charged, and its under load. I think the reason it fluctuates is that alternator would put out more voltage if it finds the battery cannot put out enough juice for the electronics).

Observation 2: I also found that if I have charged up the battery with charger (~12.6-12.8v). I will likely not see the 14.2v for very long, and this is actually good (overcharge battery would kill it).

Observation 3: I found that the "wonderful" idle engine stop feature that Honda Pilot comes with (and marketed as fuel saving feature) would actually make sure battery not charged much in stop-and-go traffic. Observation is that, when idle stop is happening, the voltage is going to12.2v, and obviously battery not being charged while engine is off. And as soon as idle stop turns off (when moving again), it goes back to 14.2v. But obviously charging just for a few minutes will not charge up the AGM battery...restarting each time actually drain more battery i would think (some might argue this is driving pattern issue). Thus resulting in constantly not charged up battery (thats why when i check in my garage, I always find the battery has 12.3-12.4v). I think the solution to this is to turn off the idle stop feature, battery voltage should improved. I am currently experimenting w/ this theory (after charging up the battery first to full 12.6v). But even if this is not the case, turning off the charging frequently definitely not helping either.
Bonus: There is something called an idlestopper, if pressing the disable idlestop button everytime i drive bothers me, i might considering DIY that in (search youtube for instruction). For now, i will start w/ proving above theory in observation 3.

Sidepoint: I dont think anyone should be driving the car for 1hr on highway just for the purpose of charging the AGM battery....its a waste of gas (gas is not cheap) and time (which i am sure none of us has too much of), not to mention the wear/tear on the car, and it contribute to unnecessary traffics and pollution... Please go get a charger to do that, so battery gets charged up while you sleep instead...w/ the higher and higher gas price, sure the return on investment would be pretty fast if driving for 1hr just for charging is a regular thing...

 

I have a gen2 Pilot, 2012 Touring, so different from your gen3 Pilots. However, I have much experience in the past 10 months using a bluetooth battery monitor + Android app, troubleshooting my unintended RPM issue as described at https://www.piloteers.org/threads/sudden-high-rpm-while-braking-shrpmwb.184327/#post-1843399 .

The battery monitor is a BM6(don't recommend the BM2 since it doesn't record data) and directly connects to the battery, and uses a phone app + bluetooth comms to show per second voltage/SoC/temp results in real time (up to 5 most current minutes) + record this data every 2 minutes long term. Its model is called BM6, is available on Amazon, and is relatively inexpensive. The real time per second data is seen in the app(and regularly scrolled off) if the engine is running or not running.

I definitely would be interested if other Pilot owners have/can get this BM6 monitor and we can share numeric results in various conditions to hopefully determine "normal"? My results confirm the expected Honda dual mode alternator in play, in general described at Honda's Dual-Mode Charging System (siu.edu) . The computer is dictating when the high voltage charging occurs vs. low voltage charging.

As varied charging behavior already mentioned in this AGM battery thread, this BM6 battery monitor will actually show you near real time when the alternator is actually charging vs. not. The cigarette lighter voltage monitors are not as precise in my experience, as well as don't long term record the numbers. I would love to compare voltage and SoC numbers seen on other Pilots using this BM6 monitor to my own. It's currently unclear to me what "normal" voltage/SoC #s should be, hence would like to compare vs. others.

As an example, in general, I am typically seeing our Pilot resting/garage voltage in the ~12.2V - 12.6V range, correlating to SoC of ~40%-80% per the BM6 app. Another example, it took 55 minutes driving time yesterday evening to go from 52%(12.35V) SoC to 100%. 30 minutes later in garage, SoC was 77%(12.64V). This morning at 8 AM in garage, SoC is 61%(12.47V). Temperature influences these results too. Maybe this is all normal, maybe not? I don't think the on board voltage monitoring/alerting via dummy lights provides sufficient detail on my gen2 Pilot, sounds like maybe similar on the gen3.

 

Honda uses a Duel-Mode Charging System. They do this to help with gas mileage by cutting the current that the alternator puts out thus less drag on the engine, better fuel mileage.
Maybe this will help.
My 2020 EX-L AWD doesn't get driver that much, we use it for travel mostly. I keep it hooked up to a Deltran Battery Tender when we don't drive it much and wouldn't over charge (just maintain) the battery.

Any expertise here on the Honda Dual-Mode Charging System? - Page 1

Any expertise here on the Honda Dual-Mode Charging System? - Page 1

www.eevblog.com

Google Honda Duel-Mode Charging System for more information.

 

Info on alternate negative ground for jump starting Pilots

Thanks Camping Randy

 

I know it's 6 months later but I just had to jump my 2019 Touring for the first time and what a PITA! Not only is this a great tip, but I found some even better ones in the comments below this video, even Camping Randy thought they were good.

1. Use the oblong steel hood latch that goes into frame to hold hood down for a ground, it's connected to the same cross member the battery ground is.
2. Just get a M6 battery post and screw that into the hole. It is said Honda did that in the '23 Trailsport.

 

I wanted to mention that we just completed a 964 mile trip from Md. to Florida. At speeds of 60, 70 and 80 mph highway driving, I figure the battery should be fairly well charged. On the last day of two days driving we traveled a little over 400 miles and pulled into the driveway. After unloading the car and later putting it into the garage, I went to start the Pilot and low and behold the warning of a low battery came up on screen. How is this possible I ask. We took the car into Honda for oil change and spoke of the battery warning. Even showed the dealer the picture I took and they said they would check it out. When the car was finished we got a list of all the things checked out including a perfect battery. No problem was found, but how is that possible I ask? Then I read on the forum about the Battery Sensor and now when we go back in a month to get a recall done, I will have them check out the battery sensor. Hope that fixes this issue.

 

Using a 24x7 bluetooth battery monitor + app and showing your mechanics/Honda the graphs over time may be helpful in your case (as well as seeing if/how this changes after they potentially make some change(s) to fix it). However, also check with your Honda dealer if you are concerned about warranty, etc... with such use. For me on my gen2 Pilot (2012), this has been non problematic thus far and just directly connects to the battery under the hood, and the small monitor sits on top of the battery, using a small amount of power from battery itself to power it. I have found the data extremely helpful and intriguing, trying to better understand the underlying logic Honda is using to determine when alternator is high power charging vs. not, when I potentially may have problems (eg, is voltage really too low and am I noticing problems when the voltage seems to be too low?), as well as the overall battery voltage and SoC at any time X for historical comparison. IMHO, I think a detailed battery monitor like this should be installed in every vehicle out there, especially useful when there are suspected electrical/charging problems. I have no doubt that both the gen3 and gen4 Pilots have different programming/physical components/etc... for its charging design, so my data shouldn't be used for these models. Nonetheless, I think it is reasonable to assume there will be similarities seen due to similar Honda design.

Regarding overall AGM battery life experience for us, for our 2012 Pilot Touring, I had replaced our original lead acid non AGM 24F battery in 10/2016 with a Die Hard AGM 34R battery(775 CCA) at ~74K miles. In the 2012 Pilot model, the 34R battery is compatible vs. the 24F, having slightly larger CCA vs. the 24F. This AGM battery lasted nearly 6.5 years and ~77K miles, replaced in 3/2023, so average of about 12K miles/year. The new 3/2023 battery replacement is a Die Hard AGM 24F(710 CCA) since I couldn't find a reasonably priced 34R AGM battery at that time. For our driving pattern, my wife drives short distance to work most days, but we also make avg of at least 1/month 3 hour long highway trip, so most miles put on with these highway trips. There is no doubt charging behaves differently at different times, but I have determined via interpretation of the data (by knowing conditions/where/how I am driving at time X and comparing to the real-time voltage/SoC/cranking voltage graphs seen with the BM6 app at the same time while I am driving, as well as the collective data over months) the variables are more complex than just short vs. long trips. Other variables include outside temperature, what accessories are on, etc... There are even times when full 14.1V-14.3V charging continuously happens at low speeds/short trips, as well as times when the low charging 12.4V-12.9V is occurring at highway speeds.

Regardless of all of this and how much the vehicle is driven(and I think a key take away point), by the time each morning comes, even when driven for an hour+ at 100% SoC the evening before parking the vehicle, SoC will typically be below 80%(summer) and below 60%(winter) due to the constant draw that the on board computer, etc... consumes while the vehicle is not running, natural decrease of voltage values as outside temperatures decline, etc.... Lately, as it has gotten colder out(in non-heated garage; outside temp ~25-40 F to date), but certainly not(yet) the extreme cold it can get in MN, morning SoC is often in the 40% - 50% range, or ~ 12.2V - 12.3V. I am eager to see if/how this changes over the next 3 months of deep winter.

As another data collection example, in the fall we went on a long vacation and the Pilot sat idle for a total of 20 days. I charged the battery fully with an external charger prior to leaving. Outside temperature was in the 40 - 70 F range during these 20 days. Battery voltage went from 12.90V - 11.88V during this time frame, SoC from 100% to 22% (both a steady continuous decline over the 20 days). Upon seeing this in return from our trip, I expected I would have problems starting the Pilot, but didn't. However, the BM6 battery monitor mentioned previously also collects "low voltage starts"(< 9.6V) and did collect the following, but ONLY for the first start on return. The Pilot then ran for 18 minutes, getting up to 37% SoC, I re-started again 35 minutes later with an acceptable 10.58V cranking volts:

Cranking voltage

Cranking time

Status

9.37V

610ms

Low

10.58V

470ms

OK

We have not had any known or perceived issues since getting the new battery in March. However, I still don't know if what I am seeing here is "normal", thus wanting comparison with other Pilots, ideally gen2, but think gen3 and gen4 should be included as well. I have plans to show some of these voltage/SoC graphs from the app soon, but plan to do so either on my sudden RPM.... post or creating a new one.