Originally Posted By: Trav
Originally Posted By: gathermewool
After reading about the ELD, I think the indications I'm seeing may be a normal, albeit unintended side effect. Over the past few days, my observations have been very consistent. It's still annoying that the low voltage causes the increased vibration, but a simple flip of the switch to turn the running lights on solves it.
That's what i am thinking after reading more about it, i just don't know enough about it to say 100%.
I'm interested in learning more about it, please share whatever you find.
From your description it sounds like everything is working.
I agree, that everything may be normal. My plug-in volt-meter just came in, so I'll be able to monitor bus voltage and ECU voltage at the same time.
Originally Posted By: Merkava_4
Originally Posted By: gathermewool
Today, while idling at a light with vibration and 12.1VDC indicated, I turned the parking lights on and the voltage almost immediately shot back up to 13.7VDC indicated.
When the voltage shot up, did the idle smooth out?
Originally Posted By: The_Eric
Originally Posted By: gathermewool
It may be that something isn't operating properly, but the indications say otherwise. I wonder if it's solely for fuel economy, or whether there's some other reason to have the voltage shift like this. I can't imagine that a constant 13.7-14VDC would cause a battery to over-charge. What do you guys think?
It's not unheard of for manufacturers to turn off charging in certain conditions- and yes it's for mileage purposes.
Like Trav, I don't know enough to say for sure if your particular case is 100% normal.
Yes, it did. Turn the lights off, voltage drops, vibration returns.
Originally Posted By: HangFire
Originally Posted By: gathermewool
That's not how it works. The use of dielectric grease between the terminal and post will cause zero issues
The way it's supposed to work, if the metal to metal contact pressure exceeds a certain PSI, conductivity is assured.
The way it worked for me is I had ever-worsening charging and high demand issues until I cleaned out all dielectric grease between the post and the cable terminal. Now I use non-flowing corrosion inhibitor spray (like NoCo NCP-2) on exterior surfaces after mating degreased, clean bare metal to metal.
You might have another problem entirely, or more than one problem...
Dielectric grease is easily penetrated and displaced by connector contact pressure, IME. It's used pretty widely, and in many applications where water exclusion is a must, or where corrosion is likely, such as copper connections and contacts. If you're not adding dielectric grease to your marine connectors, you're making a mistake - it's a must. But that's neither here nor there...As much as a weirdo maintains his cars, dielectric grease may not be all that important, but it's for sure not causing any issues.
Originally Posted By: SHOZ
Most OBDII voltage monitoring is from the ECU regulated value I think. Not the battery voltage.
Right, and that's my concern, more so than low actual voltage; because, that would be indicative of a possible ECU issue, such as a short. Based on what others have said and my continued observations, it's looking like the former is true, and that's it's normal.
Originally Posted By: zzyzzx
I don't see any problem here. It's not charging much at idle when it's warmed up because alternators don't always charge much at idle, and when it's just off a cold start, it does need to charge the battery more.
This isn't just at idle, it occurs at highway speed, and while accelerating lightly. It seems to shift back to full voltage while accelerating at higher RPM, but shifts back down to lower voltage when I let off and the AT upshifts.
