2017 Honda Charging, stays at 14.4V

[researcher]

I have 3 Honda's, various years with the Honda charging algorithm.

My 2017 Accord, 2.4L 6MT seems to be staying at 14.4V, I think. I need to watch more on my daytime drives. All my Honda's go to 14+V when headlights are on. I do recall my plug in phone charger showing varying voltage in the past. It's not exact but close. I think it used to drop even at clutch in shift. I work nights so going to work obviously lights on, full voltage.

Battery is a 2 year old Honda 51R. Last tests 2 weeks ago showed it at full CCA if not higher, I'll check again tomorrow after it sits overnight. I'm wondering if my negative load sensor is bad? How do I test that? I got home from work, put my Fluke DMM on it showed the 14.4V. I turned every electrical on I could and it held the 14.4V, quick drops to 13.0 when AC compressor and fan kicked on but right back to full.

Old school we always wanted full voltage like that. Many hate the Honda and I think would "like" this issue with stereos etc. I just want to make sure it's working correct and not trashing other stuff.

I'll keep monitoring but it doesn't get really short drives. 25-30 minutes to work and then back, mix highway and local but no real traffic.

I was going to say check the ELD, electronic load detector, it's built into the fuse box area. Not sure how they assembled it for your 17 Accord, but when I looked it was around a $5-8 part from Honda. Probably not the entire fuse box but a part connected to it.

Honda's have always had (for others who may not know) an electrical load sensor to tell the alternator to ramp up voltage, from what I remember it's for fuel economy.

So @Sequoiasoon that load sensor you mentioned, yep it could be bad. I found a link over at the Accord forums, might be helpful for you. That voltage SHOULD be changing based on the load you're asking of it, it should not be steady at 14.4V at all.

https://www.driveaccord.net/threads/eld-electrical-load-detector-known-good-output.466425/

Another link is this pdf file explaining how the ELD system works, they've had them in their cars since the 90s

https://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=1011&context=auto_pres

And with the research I've seen at honda-tech, if the ELD is disabled it will result in the high voltage output you're seeing on the Accord

https://honda-tech.com/forums/tech-...as-eld-electric-load-detector-system-3345042/

 

[Sequoiasoon]

I was going to say check the ELD, electronic load detector, it's built into the fuse box area. Not sure how they assembled it for your 17 Accord, but when I looked it was around a $5-8 part from Honda. Probably not the entire fuse box but a part connected to it.

Honda's have always had (for others who may not know) an electrical load sensor to tell the alternator to ramp up voltage, from what I remember it's for fuel economy.

So @Sequoiasoon that load sensor you mentioned, yep it could be bad. I found a link over at the Accord forums, might be helpful for you. That voltage SHOULD be changing based on the load you're asking of it, it should not be steady at 14.4V at all.

https://www.driveaccord.net/threads/eld-electrical-load-detector-known-good-output.466425/

Another link is this pdf file explaining how the ELD system works, they've had them in their cars since the 90s

https://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=1011&context=auto_pres

And with the research I've seen at honda-tech, if the ELD is disabled it will result in the high voltage output you're seeing on the Accord

https://honda-tech.com/forums/tech-...as-eld-electric-load-detector-system-3345042/

Mine on the '17 Accord is like my '19 Pilot and mounts on the negative battery terminal for $87 for OEM https://www.hondapartsconnection.com/oem-parts/honda-2013-2017-honda-accord-sensor-assembly-battery-38920t2aa04

I'll monitor the Accord closer the next couple weeks and maybe use my OBD Fusion display for easier heads up visual. I'm torn on whether I want to try changing it. We always discuss the EPA guidelines and extra MPG from thinner oils, cylinder management, alternator load, AC load (econ) etc. and how many of us say F that I want full power, full voltage, better protection.

Before these current Honda's in my fleet no other vehicles I ever owned had alternators that reduced output. That's 34 years of me legally driving and at least 10 more helping dad with his. I have had alternators rebuilt as well as upgraded for higher amperage output to cover extra halogen lights and multiple amp stereos. All of those the batteries also lasted a lot longer then the current "3 year recommendation" all the newer ones have whether that's from battery manufacturing or vehicle loads.

14V+ at idle normally meant the alternator was working correct, short of a bad diode whine and reduce amperage. Anything under that and alternator was going bad. Granted I keep most of my cars for over 10 years and as many miles as possible so my sample size is not has high as others that change vehicles and brands more frequently.

It's 52F outside, I just checked my Accord and my Pilot. Both sitting for over 15 hours. Accord is a Honda dealer FLA battery 51R, 500cca rated, 12/23 manufacture sticker. Base on battery result I see no need for putting on CTEK charger to "top off".

Pilot has a Walmart EverStart Maxx, FLA group 48, 730cca that was installed 1/21/26 with a 12/25 manufacture date. I drove it about 4 miles yesterday but that included stops at Advance Auto Parts to recycle oil and Exxon to fill up. That stayed at 14.2V the whole time. The dealer did replace the load sensor on that February of 2022 due it saying low battery (with a new battery just installed). Pilot also just had a 1000 mile round trip to VA and back for Easter that included day and night travel times.

 

[Sequoiasoon]

I just ordered some rear pads from Rock Auto for the Accord. I figured I'd look at the options. I don't recall ever using WELLS and Standard Motor used to be OK a couple decades ago but I think often referred as to as an "emergency, only available version" after that and it's more $$ than OEM.

 

[Mainia]

This "CAFE Standard" induced charging algorithm has frustrated me too, on my 2018 Hyundai Kona.
I use this tester to keep track of my batteries.

https://www.amazon.com/TOPDON-BT200-100-2000CCA-Automotive-Alternator/dp/B08CMPY86M?ref_=ast_sto_dp

With 3 different AGM's in it's life of owning the car they ALWAYS live a life of extreme under charging and me doing charging with a AGM charger multiple times a month. If I leave my headlights on or rear window defroster on I am charged at 95 to 100%. Otherwise I am at 40 to 50%, and killing my battery in my normal use, that is the same as my 95% to 100% charge use with the headlights/rear defrost on. This post has made me look on how to cheat the CAFE charging algorithm. One option is to disconnect the the ELD sensor on the negative battery cable and have the battery to fall back on the ECU/Hyundai fall back algorithm and monitor for over charging. The other option is add a second negative cable directly from the battery to the chassis. Here the thought is the pixies have a bypass and the ECU would keep the charging up while still monitoring the total voltage and the ECU would still be in semi control wile being obfuscated. I am thinking of going this last route since I already have dual negative chassis cable mounting points with a Big 3 charging system re cabling with high $ oxygen free copper cables.Both leading to the battery sensor in an OEM style hookup. One longer custom cable away from separating them and then do some monitoring. Any comments from electrical wizards welcome, if this semi-bypass idea is sound, allowing pixies to subvert some of the monitoring of a one feed cable? I suppose that might not work if brake and throttle position are very high on the list. Well, there a 2 options here to test.

 

[JHZR2]

I don't think that is technically correct. A battery does not really "pull" current like a load - its actually a supply by definition.

In order to push against the supply enough for it to receive a charge you need an "overvoltage" of at minimum 1V over nominal. So with a 12V, 6 cell battery being around 12.6V at full charge, a float usually technically requires an additional 1.0V absolute minimum.

Both my Toyota and Nissan's seem to float around 13.8V, they charge at around 14.2V. Constant 14.4V seems high to me but possibly OK. Its definitely not a float voltage for a lead acid battery.

Vt = Voc +/- I*R

Impedance (which varies with state of charge and some chemical phenomena that affect charge transfer) affects over voltage requirement to provide a certain amount of charge current. If voltage is fixed, the amount of charge current the battery will accept is set accordingly.

 

[iCurious]

I don't see what is the problem here with a charging voltage of 14.4. It's not over charging.

 

[researcher]

Mine on the '17 Accord is like my '19 Pilot and mounts on the negative battery terminal for $87 for OEM https://www.hondapartsconnection.com/oem-parts/honda-2013-2017-honda-accord-sensor-assembly-battery-38920t2aa04

I'll monitor the Accord closer the next couple weeks and maybe use my OBD Fusion display for easier heads up visual. I'm torn on whether I want to try changing it. We always discuss the EPA guidelines and extra MPG from thinner oils, cylinder management, alternator load, AC load (econ) etc. and how many of us say F that I want full power, full voltage, better protection.

Before these current Honda's in my fleet no other vehicles I ever owned had alternators that reduced output. That's 34 years of me legally driving and at least 10 more helping dad with his. I have had alternators rebuilt as well as upgraded for higher amperage output to cover extra halogen lights and multiple amp stereos. All of those the batteries also lasted a lot longer then the current "3 year recommendation" all the newer ones have whether that's from battery manufacturing or vehicle loads.

14V+ at idle normally meant the alternator was working correct, short of a bad diode whine and reduce amperage. Anything under that and alternator was going bad. Granted I keep most of my cars for over 10 years and as many miles as possible so my sample size is not has high as others that change vehicles and brands more frequently.

It's 52F outside, I just checked my Accord and my Pilot. Both sitting for over 15 hours. Accord is a Honda dealer FLA battery 51R, 500cca rated, 12/23 manufacture sticker. Base on battery result I see no need for putting on CTEK charger to "top off".

View attachment 332468

Pilot has a Walmart EverStart Maxx, FLA group 48, 730cca that was installed 1/21/26 with a 12/25 manufacture date. I drove it about 4 miles yesterday but that included stops at Advance Auto Parts to recycle oil and Exxon to fill up. That stayed at 14.2V the whole time. The dealer did replace the load sensor on that February of 2022 due it saying low battery (with a new battery just installed). Pilot also just had a 1000 mile round trip to VA and back for Easter that included day and night travel times.

View attachment 332469

Thanks for showing how your ELD is designed, I must've looked up the wrong one, no problem.

But thinking about your post, it does remind me of how on my 96 Civic, the stock alternator would undercharge the battery to save fuel economy. I kept replacing batteries every 3 or so years. When that stock alternator died, got an aftermarket (TYC brand, new not refurb) and that did not have the fuel economy mode. What happened? Well that's when the batteries began to last a lot longer about 5.5 years! It was outputting more, keeping the battery charged!

Remembering that, my advice is to say forget trying to return to the original design and fixing this, since it's at the max voltage of the ELD, and it's keeping the batteries lasting longer, looks like for once when something became defective it was a GOOD thing!

 

[Sequoiasoon]

This "CAFE Standard" induced charging algorithm has frustrated me too, on my 2018 Hyundai Kona.
I use this tester to keep track of my batteries.

https://www.amazon.com/TOPDON-BT200-100-2000CCA-Automotive-Alternator/dp/B08CMPY86M?ref_=ast_sto_dp

With 3 different AGM's in it's life of owning the car they ALWAYS live a life of extreme under charging and me doing charging with a AGM charger multiple times a month. If I leave my headlights on or rear window defroster on I am charged at 95 to 100%. Otherwise I am at 40 to 50%, and killing my battery in my normal use, that is the same as my 95% to 100% charge use with the headlights/rear defrost on. This post has made me look on how to cheat the CAFE charging algorithm. One option is to disconnect the the ELD sensor on the negative battery cable and have the battery to fall back on the ECU/Hyundai fall back algorithm and monitor for over charging. The other option is add a second negative cable directly from the battery to the chassis. Here the thought is the pixies have a bypass and the ECU would keep the charging up while still monitoring the total voltage and the ECU would still be in semi control wile being obfuscated. I am thinking of going this last route since I already have dual negative chassis cable mounting points with a Big 3 charging system re cabling with high $ oxygen free copper cables.Both leading to the battery sensor in an OEM style hookup. One longer custom cable away from separating them and then do some monitoring. Any comments from electrical wizards welcome, if this semi-bypass idea is sound, allowing pixies to subvert some of the monitoring of a one feed cable? I suppose that might not work if brake and throttle position are very high on the list. Well, there a 2 options here to test.

Try it and see what shows. You can do an OBD2 plug in dongle and phone app or the cell phone charger with voltage display to get a good reference.

 

[Sequoiasoon]

Thanks for showing how your ELD is designed, I must've looked up the wrong one, no problem.

But thinking about your post, it does remind me of how on my 96 Civic, the stock alternator would undercharge the battery to save fuel economy. I kept replacing batteries every 3 or so years. When that stock alternator died, got an aftermarket (TYC brand, new not refurb) and that did not have the fuel economy mode. What happened? Well that's when the batteries began to last a lot longer about 5.5 years! It was outputting more, keeping the battery charged!

Remembering that, my advice is to say forget trying to return to the original design and fixing this, since it's at the max voltage of the ELD, and it's keeping the batteries lasting longer, looks like for once when something became defective it was a GOOD thing!

I wonder if just disconnecting off the battery terminal for a couple minutes it has any "reset" function? The higher charge state doesn't bother me too much as my old school mentality kicks in as well as knowing it would be that if I only drove at night or headlights on during the day.

I believe all of the newer versions are controlled via ECU/PCM. I know the stereo upgrade group like I used to do hate it because even getting a high output alternator the volts get cut down so the amps don't rock as hard as a result. Big wire upgrades etc don't help them either.

Just that it's not working as designed so me questioning how to test that.

 

[researcher]

I wonder if just disconnecting off the battery terminal for a couple minutes it has any "reset" function? The higher charge state doesn't bother me too much as my old school mentality kicks in as well as knowing it would be that if I only drove at night or headlights on during the day.

I believe all of the newer versions are controlled via ECU/PCM. I know the stereo upgrade group like I used to do hate it because even getting a high output alternator the volts get cut down so the amps don't rock as hard as a result. Big wire upgrades etc don't help them either.

Just that it's not working as designed so me questioning how to test that.

Yup I do remember the higher output rating at 14.4v for amps in car audio. And I wouldn't worry either about the higher charge level, most likely it's going to prolong the life of the battery.

But I hear you about getting to be able to diagnose/test your existing ELD, I think one of my links was showing that. Be interested to find a service manual level type diagnostic.

 

[willbur]

I don't see what is the problem here with a charging voltage of 14.4. It's not over charging.

true. Typically base voltage + 2 (12.6+2) with all accessories on at idle is a healthy charging system

 

[Sequoiasoon]

ELD / ECU is working at least at times. I'm not sure what it's looking for on time after start etc. I drove from Long Island to Dover, DE last Saturday. Somewhere on the NJ turnpike I looked at it and the gauge showed 13.1V, not long after it started to rain so headlights and wipers on and back to 14V+.

I swapped cars with my son and his 2010 Forte is old school, no variable alternator. 14.4V when engine is running.

 

[D1dad]

I used to use a solar charger on the back shelf when I flew 3 weeks out of the year. Kept the battery up while in the Airport parking lot. I just had to park in the outside lots or top level of the parking garage.

That’s what my son does with his truck. Lives in an apartment complex and it’s his only option. Plus, it’s a Titan so it has Nissans infamous charging system.

 

[researcher]

ELD / ECU is working at least at times. I'm not sure what it's looking for on time after start etc. I drove from Long Island to Dover, DE last Saturday. Somewhere on the NJ turnpike I looked at it and the gauge showed 13.1V, not long after it started to rain so headlights and wipers on and back to 14V+.

I swapped cars with my son and his 2010 Forte is old school, no variable alternator. 14.4V when engine is running.

Thanks for the update, yep it sounds like it works when it wants to. But the good news is, most of the time it's at max charge which is good for your battery!