[DannyV]

So I have been going crazy ever since I had a no start and a little negative terminal corrosion. I jumped it, bought it to mutiple places that said it was Alternator, Battery, Etc!

Since then, I replaced the battery, and battery sensor. I’ve been busy checking voltage and all that, bought a voltmeter, still thinking my car is messed up, but so far it has not died out. I’m wondering if this sounds normal? Is this all in my mind now???? Since then, this is what happens:

Battery is at 12.6v when off. After start, it jumps to 14.3v and then drops slowly back to 12.7v.

Once I turn on headlights, it stays at 14.3v. Please note alternator is same voltage on everything I just mentioned.

So is it normal for battery to stick around 12.7v with car started but nothing on? Car has not died yet and has a strong start Up. Battery never goes below 12.6v after being shut off.

I was about to bring it to an expensive electrician mechanic to see if there’s wiring issues.

Why you ask? Because when I pull battery sensor cable off, car stays at even 14.5v. But with it connected, the above voltages fluctuate between 12.7. - 14.3 depending on what I turn on in car. Is everything normal? Should I just drive and hope for the best. Thx

 

[Cincy19]

Yes that is normal for Hondas. The battery sensor switches between high voltage charge and lower voltage charge depending on load.

 

[ActnJksn]

Mine tends to stay around 14.2 to 14.4 volts while driving. My dashcam backup battery draws 0.2 to 0.4 volts on top of this.

 

[DannyV]

Yes that is normal for Hondas. The battery sensor switches between high voltage charge and lower voltage charge depending on load.

Ok Thank you for that info. Hope it works out.

 

[DannyV]

Mine tends to stay around 14.2 to 14.4 volts while driving. My dashcam backup battery draws 0.2 to 0.4 volts on top of this.

How do you know your voltage while driving? Do you stop, and measure it somewhere? I would like to find this out. It will tell me a lot.

 

[WiiMaster]

How do you know your voltage while driving? Do you stop, and measure it somewhere? I would like to find this out. It will tell me a lot.

There are many options to do this. A common option is something that plugs into the 12V outlet and gives you a voltage readng.

 

[Rygrego]

So I have been going crazy ever since I had a no start and a little negative terminal corrosion. I jumped it, bought it to mutiple places that said it was Alternator, Battery, Etc!

Since then, I replaced the battery, and battery sensor. I’ve been busy checking voltage and all that, bought a voltmeter, still thinking my car is messed up, but so far it has not died out. I’m wondering if this sounds normal? Is this all in my mind now???? Since then, this is what happens:

Battery is at 12.6v when off. After start, it jumps to 14.3v and then drops slowly back to 12.7v.

Once I turn on headlights, it stays at 14.3v. Please note alternator is same voltage on everything I just mentioned.

So is it normal for battery to stick around 12.7v with car started but nothing on? Car has not died yet and has a strong start Up. Battery never goes below 12.6v after being shut off.

I was about to bring it to an expensive electrician mechanic to see if there’s wiring issues.

Why you ask? Because when I pull battery sensor cable off, car stays at even 14.5v. But with it connected, the above voltages fluctuate between 12.7. - 14.3 depending on what I turn on in car. Is everything normal? Should I just drive and hope for the best. Thx

Totally normal. 12.6-12.7 is a perfectly charged battery. Hondas add voltage as load increases.

 

[DannyV]

Totally normal. 12.6-12.7 is a perfectly charged battery. Hondas add voltage as load increases.

Yes, I just read a chart for accords that says when idle, sensor will do a low voltage charge (12.5+) and when lights go on, it does a max charge (14.3+). I can’t believe I spent a whole week going crazy, when it was probably the battery which was down to 240 cca, tested by Napa. I probably didn’t even need the sensor, but it did look really bad! Thx everyone for the taking the nerves away. I was about to drop it off to an electrical specialist!

 

[WiiMaster]

I wouldn't feel too bad about replacing the sensor considering they were recalled anyway.

 

[DannyV]

There are many options to do this. A common option is something that plugs into the 12V outlet and gives you a voltage readng.

Ok, perfect. Didn’t know they make something like that. Thx.

 

[DannyV]

I wouldn't feel too bad about replacing the sensor considering they were recalled anyway.

Yea, plus I figure the new one still has the lead plating in terminal, the other one might cause corrosion with that copper exposed.

 

[ActnJksn]

How do you know your voltage while driving? Do you stop, and measure it somewhere? I would like to find this out. It will tell me a lot.

I have a digital voltage gauge hooked up. Transferred over from my crappy Fit charging system and upgraded audio system, I wanted to monitor my voltage.

 

[blue9732]

The Accord is notorious for crank no starts if battery voltage drops too low while cranking. It'll just keep cranking but the engine won't start. I've experienced this a few times if car has been used for short in town trips, especially in the cold Canadian winter... I think the fluctuating voltages while running is Honda's way of squeezing 0.2 more MPGs out of the engine at the cost of batteries.

 

[0dyfamily]

@DannyV , is your Accord a 4-cylinder?

OF

 

[blue9732]

@DannyV , is your Accord a 4-cylinder?

OF

yep 2.4. I remember researching the problem a while ago and found a post that explained the problem. The ECM needs a certain voltage during cranking to fire up the engine and if it doesn't see that voltage it won't start but it will crank.

 

[bamm]

Yes, I just read a chart for accords that says when idle, sensor will do a low voltage charge (12.5+) and when lights go on, it does a max charge (14.3+). I can’t believe I spent a whole week going crazy, when it was probably the battery which was down to 240 cca, tested by Napa. I probably didn’t even need the sensor, but it did look really bad! Thx everyone for the taking the nerves away. I was about to drop it off to an electrical specialist! View attachment 564791

It can make having the alternator tested wrong by a lot of auto parts places, more fun for sure when you need a concrete answer.

 

[0dyfamily]

@blue9732 (and @DannyV ) , along with removing the parts store starter and installing an OEM starter, I installed a Group 24F battery into my daughter's 2011 LX sedan, and never looked back. That, coupled with a genuine OEM starter, made all the difference.

OF

 

[DannyV]

@0dyfamily @blue9732 Hey guys, Sry just seen messages. Been messing with car all day.

But Yes, I did put a bigger battery, Diehard 700cca! Why not lol. Also as you’ve probably read earlier, A new Battery Sensor, and new battery Hold down. This is where I’m at and what I’ve gathered:

Car sits at 12.6 off. Jumps to 14.4 after start, then creeps back to rest at 12.7, unless loaded with lights, A/C, etc. Then it goes to 14.4 again. So supposedly that’s normal.

I also bought a 12v voltage reader that I can plug in to cigarette lighter, so tomorrow will be my first test drive, voltage read, and all that.

My only concern, and this may sound confusing. There’s a connector that goes to the sensor. It has three wires. The voltage at the red and green wire are 12.3.

The voltage at the blue wire fluctuates between 7-8.5, but I also had the connector at the alternator unplugged when checking this voltage, it’s a yellow wire. From my understanding of the pics and link below, that yellow wire at the alternator is the same as the blue wire at the Battery connector. The only thing I have not done, which I forgot, is to check the voltage of the blue wire while the yellow one at the alternator is plugged in. The guy in the link/pics below mentions “waves”, maybe that’s what the fluctuation is, 🤷‍♂️

To be honest, I have no idea what’s going on, if anything at all. Lol, Im testing everything now, probably for no reason. I’m going to leave a pic of the wire test tutorial.

Anyway, thanks for the replies and help. I mean my battery is always at 12.68V when off, so that kinda says it’s charging, right? Wouldn’t it be at 12v or 11v if not? But like I said, i’ll know a lot more tomorrow after my first test drive with the voltage meter plugged into my cigarette lighter.

pics and link below of wire test. It’s another guys results on exact sensor and wire. Thx again.

Honda Accord CR2 2013-2019 battey sensor operation and testing | P & G Motors - Seven Hills

 

[0dyfamily]

Car sits at 12.6 off. Jumps to 14.4 after start, then creeps back to rest at 12.7, unless loaded with lights, A/C, etc. Then it goes to 14.4 again. So supposedly that’s normal.

Totally normal.

I have a ScanGauge ii on my Acura TL and Honda Odyssey. They both do the same thing on that voltage display.

OF

 

[blue9732]

I agree with Odyfamily. The charging on the Accord is two stage.... High when it needs it and low when it doesn't..... It's its way of saving MPGs. As long as the car has a needed voltage it'll start and run and run... I can double check your specs on my accord if needed. I worry a little about your blue line voltage of 8 volts as the LIN should be about 0-12v. The LIN should really be check with an oscilloscope but a voltmeter might give an indication.... If your car starts after being driven for 10 minutes, it's charging or else you'd end up with a dead battery and the car wouldn't even crank over.... LIke I said, I can measure voltage on my accord if needed..... I also found a TSB for the battery sensor ....