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Your battery is not fully charged and perhaps not returning to fully charged when driving.
Yep. I pointed this out way, way, way back (a couple years now) in Posts #32/#33. You commented regarding the ground side, I didn't say anything, but I also stated the positive side could have built-up oxidation/corrosion. "If" that's the case and there was a plethora of green/blue gunk in that positive wire (lurking under the protective rubber sheath insulation), the resistance can increase substantially and the alternator may never be able to overcome the resistance of green/blue gunk to supply voltage back to the battery to gain a full 12.6V.
Trailblazer - You need some $$ to purchase a multimeter which measures amperage? You should have been done w/ this two weeks ago.
Here's the one absolute unequivocal fact you still do not know about this situation: You do not know what amperage you are drawing when the car is sitting on its **** going nowhere. That is your starting point. What's the magic number again? <50mA
Nope...I'm already suspecting the door jamb switches, so Ill start with that. If they're not the culprit, then it's onto the clock. Also, since I have two spare working clocks, I'm going to check the resistance on those and then check the one in the car. This is to see if maybe the windings are shorted. I'll compare the results to see if there's a difference.
You're going to drive out to Colorado (Estes Park), up to the Grand Tetons (Wyoming), North to Mount Robson (British Columbia), take a ferry across Lake Michigan, and hike down the Appalachian Trail to resolve this issue? The reason they have an "Amp" scale on a multimeter is to measure amperage.
Dave, I think you should think of this in comparison to electrical system in your home. You will always have 120 volts at the circuit whether you have a load on it or not. What varies on your circuit is the amperage. No load = 0 amps at 120 volts. As you add load to the circuit your amps goes up to say the breaker capacity of 20 amps, but all this time the voltage is still at 120 volts. (I realize there is voltage drop across the length of a wire etc, in your home circuit, but it is small in comparison to load) If you think of water in pipes, volts are the pressure, while amps are the volume of water moving through the pipe.
That was why Norm was wanting you to measure amps (in your case milliamps).
Dave, I think you should think of this in comparison to electrical system in your home. You will always have 120 volts at the circuit whether you have a load on it or not. What varies on your circuit is the amperage. No load = 0 amps at 120 volts. As you add load to the circuit your amps goes up to say the breaker capacity of 20 amps, but all this time the voltage is still at 120 volts. (I realize there is voltage drop across the length of a wire etc, in your home circuit, but it is small in comparison to load) If you think of water in pipes, volts are the pressure, while amps are the volume of water moving through the pipe.
That was why Norm was wanting you to measure amps (in your case milliamps).
Thanks Pat. Good portrayal. So, Dave - you got this, as Pat suggested. The vehicle (key term) "draws" amps, for this discussion it does not draw voltage - the devices draw amps from the battery. Just like the main service panel in your home (except in AC) you have 100V, 200V, 400V at the service panel - the power company continually delivers that voltage to your main service panel. Next, you have circuit breakers - each rated 5A, 10A, 20A, 30A, etc. - each circuit "draws" amperage from the service panel, but you still have 100V, 200V, 400V at the service panel.
Guys, I get what you're saying, but if the courtesy light fuse is plugged in and causing the drop in voltage, and then I pull that fuse and my voltage stays steady, then the voltage drop has to be in one of the circuits protected by that fuse, correct?
Oh and BTW Norm, my battery does take a full charge up to 12.6 volts. My starting point yesterday was actually at 12.6, but when I connected the negative terminal, it would only seem logical that I would incur a slight drop, right?
Also, I dunno if this has any bearing on the issue, but as I said, I was going to check the resistance on all three of my clocks. All were tested with no wires connected and the light harness removed.
To do the test, I put my meter on ohms and the positive lead on the clock terminal and the negative lead on the clock case.
Dave - Truly, I have been trying to assist you & I will continue to do so. I’m not going to bend to further discussions outside troubleshooting I’ve already discussed in attempts to help you understand. You have not answered any questions I have asked. You are unwilling to use a MM to establish your cars nominal amperage which has been discussed. If you’re unwilling to measure your amperage I cannot assist you further.
Dave - Truly, I have been trying to assist you & I will continue to do so. I’m not going to bend to further discussions outside troubleshooting I’ve already discussed in attempts to help you understand. You have not answered any questions I have asked. You are unwilling to use a MM to establish your cars nominal amperage which has been discussed. If you’re unwilling to measure your amperage I cannot assist you further.
All I'm trying to do Norm is understand why voltage drop would not be an indicator of a parasitic drain.
Let’s begin with the basics. Devices on your car draw “amps” from your battery to run devices in your car. If you have a 50Ah (AmpHr) battery in your car, you can supply 50 Amps for one hour if you are drawing 50 Amps. At this point your battery is 100% dead. If you’re drawing 25 Amps your battery is dead in 2 hrs. If you are drawing 5 Amps you can supply 5 Amps for 10 hrs before your battery is dead. If you are drawing 1 amp from this fully charged 12.6V (50Ah) battery, how many hours can you draw 1 Amp (before the battery is completely dead)? Don’t interject any what if this and that, just answer the question.
Let’s begin with the basics. Devices on your car draw “amps” from your battery to run devices in your car. If you have a 50Ah (AmpHr) battery in your car, you can supply 50 Amps for one hour if you are drawing 50 Amps. At this point your battery is 100% dead. If you’re drawing 25 Amps your battery is dead in 2 hrs. If you are drawing 5 Amps you can supply 5 Amps for 10 hrs before your battery is dead. If you are drawing 1 amp from this fully charged 12.6V (50Ah) battery, how many hours can you draw 1 Amp (before the battery is completely dead)? Don’t interject any what if this and that, just answer the question.
The voltage which remains in a fully depleted battery contains how many volts? See Eric’s posted image. What is the voltage when the state of charge reaches zero (0)?
We won’t get into minuscule nit-picky minutia because the relationship is not exactly 1:1 but instead logarithmic. But, you get the notion you’ve depleted the battery of amperage. So, what’s important is the amperage you’re drawing not the voltage you are attempting to measure using your method of logic.
The voltage which remains in a fully depleted battery contains how many volts? See Eric’s posted image. What is the voltage when the state of charge reaches zero (0)?
There are 1,000 milliamperes per 1 ampere. Your car should draw <50mA everything off just sitting there. Greater than >50 mA is a serious parasitic draw. At the very start you want to assess “if” you have a parasitic draw - which is demonstrated if you have >50mA draw in a car with everything turned off. If you read you have 200mA draw in a non-running vehicle at rest with everything off, start pulling fuses. When you pull a fuse and the reading goes below 50mA, that is the circuit drawing excessive amperage producing parasitic draw.
We could, but we won’t, get into a discussion regarding electrical “potential” where can relate amperage to voltage in a 1:1 relationship but that far exceeds the realm of this discussion. But, hopefully you see the futility in measuring voltage to determine parasitic draw - it’s an endless loop. Amperage is what you need to be measuring firsthand. So, again I can’t overstate the importance of measuring amperage - that’s where you begin, then identify the circuit causing excessive amperage draw.
If you can identify you have excessive amperage draw (>50mA), and pull a fuse and the amperage falls below <50mA, you’ve identified the circuit. At that specific point in the assessment/diagnosis you may wish to identify the device &/or wire using the wiring diagram as well as continuity and resistance of those wires in “that” circuit.
We could, but we won’t, get into a discussion regarding electrical “potential” where can relate amperage to voltage in a 1:1 relationship but that far exceeds the realm of this discussion. But, hopefully you see the futility in measuring voltage to determine parasitic draw - it’s an endless loop. Amperage is what you need to be measuring firsthand. So, again I can’t overstate the importance of measuring amperage - that’s where you begin, then identify the circuit causing excessive amperage draw.
That makes sense Norm, but how do you explain the fact that when I began my troubleshooting, I removed the radio fuse and had a voltage drop of almost 1 volt over a 15 hour time frame, I then installed the radio fuse and removed the fuse for the courtesy light circuit. Over a 12 hour time frame, I had a drop of just .21 volts, which tells me that the affected component is in that fuse circuit. At this very moment, the courtesy light fuse is installed and I have removed the door jamb switches. I took my initial reading 3 hours ago (and mind you, I didn't charge the battery) and it was 12.17 volts across the battery. Now, 3 hours later, it's 12.13. I'm not an electrical genius by any stretch of the imagination, but if it's holding steady with the door jamb switches removed, then therein lies the issue.
Voltage drop of a fully charged 12.6V DC battery “can” be an indication of parasitic drain. Note I said can be because a brand new fully charged DC battery would not yield to sulfation and reduce battery voltage while an old battery which has already yielded 2,000 cycles and continuous sulfation over 10 years could be expected to discharge voltage readily without even being hooked up.
Dave, I’m pretty much “done” with it. If you aren’t going to assess the amperage draw on your vehicle I’m not involving myself with your illusions of malinformed diagnoses.
Dave, I’m pretty much “done” with it. If you aren’t going to assess the amperage draw on your vehicle I’m not involving myself with your illusions of malinformed diagnoses.
I gotta agree with this. I do electronics failure analysis for a living, as in every day I troubleshoot electrical failures, and we always use an ammeter to measure current drain on a circuit node. That is the #1 analysis method that we use.
Ok..this has gone way too deep. Here's what my plan is....I'm already pretty sure that the problem is the door jamb switches. I will replace them today and see what happens.
Dave,
you are correct in thinking a voltage drop also indicates a current draw. That is why battery voltage drops when you turn the key on, engage the starter, and yes, plug in the fuse that powers your courtesy lights. Replacing the door switches is a good low-cost move, but may not be the cause of the problem. The door switches are a very simple and for the most part effective device but they can grow corrosion and/or rust on them that could cause a small enough electrical connection that it will draw the battery down without turning on the lights. You are also correct that knowing the precise amount of current drain is irrelevant if you have isolated the circuit causing the problem.
Keyboard Commandos that reply to themselves and say their way is the ONLY way to solve a problem are just a distraction. Voltage and current are inseparably related in a battery powered system so you took the long road and you got there! You may have to troubleshoot further into that circuit if there are more systems on the fuze than the lights. Does your car have a key buzzer that could be bad?
Dave,
you are correct in thinking a voltage drop also indicates a current draw. That is why battery voltage drops when you turn the key on, engage the starter, and yes, plug in the fuse that powers your courtesy lights.
Yes, with the condition that the current drain must be high enough to effect a measurable decrease in voltage in a given time frame.
Monitoring current will provide an immediate result that is independent of the current amplitude. Monitoring voltage will take time, and the smaller the current drain, the longer the time it takes for a measurable voltage change on a 12 Volt, 850 CCA battery.
Last edited by Fun71; April 23rd, 2022 at 10:01 AM.
Yes, with the condition that the current drain must be high enough to effect a measurable decrease in voltage in a given time frame.
Monitoring current will provide an immediate result that is independent of the current amplitude. Monitoring voltage will take time, and the smaller the current drain, the longer the time it takes for a measurable voltage change on a 12 Volt, 850 CCA battery.
Are you recharging the battery in between each fuse pull/install?
Yup...actually between the 1st and 2nd test, but between the 2nd and 3rd test the drop was so negligible, I didn't bother. Now I'm on the 4th test, and yes, I started with my battery charged to 12.6
Last edited by 72455; April 23rd, 2022 at 04:50 PM.
Yup...actually between the 1st and 2nd test, but between the 2nd and 3rd test the drop was so negligible, I didn't bother. Now I'm on the 4th test, and yes, I started with my battery charged to 12.6
getting in your car could be enough to wiggle the door switch and or wires.
Those wites/connections have been wiggling/hanging/vibrating for 50 years.
Might be a good time to clean all your grounds , check all your connections , clean and apply dialectic grease where needed.
Oh and the head light/dimmer switch can get moody.
i know its easy to pull the ground or put in a old school throw switch but I was thinking of a keyless remote disconnect something like this.
Although if the customer likes the idea I would have to research which ones are quality.
Ok, so after coming to the conclusion that the cause was a ground issue under the dash, and not feeling like messing with it, at the end of my troubleshooting, I decided to call it a day and just use a battery tender. I'd been doing this since I started this adventure.
Fast forward to this past Tuesday, when, after driving it to work, I decided (on a whim), to leave the tender off and see what happens. So over the past week, I would check the voltage to see if there was still an issue. Here are the results:
As you can see, there was no drop. If you were to ask me why, all I can tell you is the only things I've done electrically was change a broken circuit breaker a couple months ago for my power seat..
... and clean the terminals for my voltage gage a couple weeks ago.
All I know is I'm calling it good and putting the tender away.
Last edited by 72455; August 6th, 2023 at 08:49 AM.
UPDATE:
Ok, so after coming to the conclusion that the cause was a ground issue under the dash, and not feeling like messing with it, at the end of my troubleshooting, I decided to call it a day and just use a battery tender. I'd been doing this since I started this adventure.
Fast forward to this past Tuesday, when, after driving it to work, I decided (on a whim), to leave the tender off and see what happens. So over the past week, I would check the voltage to see if there was still an issue. Here are the results:
As you can see, there was no drop. If you were to ask me why, all I can tell you is the only things I've done electrically was change a broken circuit breaker a couple months ago for my power seat..
... and clean the terminals for my voltage gage a couple weeks ago.
All I know is I'm calling it good and putting the tender away.
I don't know how you reached the conclusion the cause was a ground issue under the dash w/o data to substantiate the existence of the parasitic draw on that circuit; and, since you replaced a broken/defective power seat circuit breaker w/o having measured (in both cases) the amperage of each circuit, I have about zero confidence of one versus the other. None-the-less, you serendipitously arrived at finding the issue & correcting the issue. Make it so Number One.
I don't know how you reached the conclusion the cause was a ground issue under the dash w/o data to substantiate the existence of the parasitic draw on that circuit; and, since you replaced a broken/defective power seat circuit breaker w/o having measured (in both cases) the amperage of each circuit, I have about zero confidence of one versus the other. None-the-less, you serendipitously arrived at finding the issue & correcting the issue. Make it so Number One.
Yup...it was either totally by accident or a coincidence...either way, I got it...lol
I keep a tender on all my vehicles to extend the life of the batteries. The Optima Red Top in the Cutlass has a tag with 4/06 so it appears to be worth the effort.
April 22nd, 2022, 02:56 PM
