Parasitic Battery Drain

[andyofcolumbusmerkur]

I actually agree with you that using that old school method is a great way to find even a small parasitic drain on an 80's car. Ed saw someone use a different method at some point and mentioned measuring off the back of a fuse. You wanted to prove him wrong I guess. Or didn't know that type of fuse had a little test tab on the back, or were confused about that for some reason. He had to literally draw a picture for you. A lot of times you guys are butting heads for no real reason. Sort of like this dumb thread. Sure it is hard to measure a very small amount of current through a large fuse. I would imagine the drop voltage test and also the infrared gun test would struggle at that. That guy fordtechmakuloco talks about the limits of various tests and his approach. I never thought of using that IR gun to diagnose a parasitic drain but look how fast he found it. So I am learning new things all the time. Which is why I read stuff on forums. But whatever you are doing is a detracting element for Merkur ownership in general.

[andyofcolumbusmerkur]

You can measure mmAmps at the fuses by touching the pos and neg probe to the metal top sides of each fuse.

YMMV

Yes, but
I think this is confusing, since you are measuring voltage drop then looking at a chart to see how much current (amps) is flowing. That amp hound the car wizard is using is doing the same thing, measuring voltage without removing fuses. So like most cases, 100's perhaps, you are not really incorrrect in your statement. But sure to get called a complete doofus for not using the correct term or a multimeter that only measures to .01 and not .001

[brokencase]

But whatever you are doing is a detracting element for Merkur ownership in general.

Whatever I'm doing?
Andy - I do not do projects like these on a whim...
viewtopic.php?f=29&t=39625&hilit=DIY+Borla
viewtopic.php?f=29&t=34066
viewtopic.php?f=29&t=36128
viewtopic.php?f=29&t=32548&start=15

I just took a gander at your posts for the past few years and I can't find a post where you have done any kind of step by step project on a Merkur.

Andy, Please dish up some original content so we can critique it.

[Ed Lijewski]

You can measure mmAmps at the fuses by touching the pos and neg probe to the metal top sides of each fuse.

YMMV

Yes, but
I think this is confusing, since you are measuring voltage drop then looking at a chart to see how much current (amps) is flowing. That amp hound the car wizard is using is doing the same thing, measuring voltage without removing fuses. So like most cases, 100's perhaps, you are not really incorrrect in your statement. But sure to get called a complete doofus for not using the correct term or a multimeter that only measures to .01 and not .001

When I wrote that I wasn't speaking from knowledge or experience re milliamps, but I felt certain using a multimeter on those tips was a valid first step. I was open to learning how to proceed next as did occur in this thread.

Thanks very much for your support!

YMMV

[milehighXR]

I assume this demonstrated the wisdom that, in cold weather especially, putting a load on the battery revives its potential to some degree. Commonly the suggested load is turning on the headlights for 30-45-60 seconds before trying to start the engine in zero or lower F temps. The multimeter load is really minuscule but it clearly stimulated a chemical reaction that produced a voltage increase.
YMMV

I have never heard that nugget ed, thanks for that, ill try it next really cold day.

[brokencase]

That amp hound the car wizard is using is doing the same thing, measuring voltage without removing fuses.

..and it looks the Amp Hound is able to measure sub millivolt voltages, i.e., better than most multimeters.

https://www.mactools.com/products/et74
"Can detect currents as low as 5mA, easily find any parasitic drain"

Notice that it is still only good to around 5 ma. Even your Harbor Freight meter, when set to milliamps, and you pull fuses can measure accurately
down to a single milliamp and even less.

So, I think I'll forgo the $125 and just use my regular DMM set to milliamps and pull fuses. It isn't that time consuming.
It's hard to justify a $125 tool for a circumstance that is seldom encountered...even in a professional setting.

You are probably better off pulling the fuses in the Scorpio anyway. You really need to inspect the copper fuse contacts.
They oxidize. When I acquired my Scorpio I once ran into a no start situation. I troubleshooted with the EVTM and knew what fuse was involved.
I pulled the fuse out and it was fine. I plugged it back in and the car started.

After that I pulled every fuse and relay and cleaned the contacts with emery paper.
Any contact that wasn't biting well into the fuse blade I gave a small squeeze with some fine needle nose pliers.

But Andy, in all fairness, If I ever come across a case where my battery is going dead in hours instead of days I will attempt the voltage drop method.

[Ed Lijewski]

Dean:

I asked above, does the ABS computer have KAM? I wouldn't be surprised if it does re remembering each wheel sensor "good" signal during a cold start-up (battery disconnect) system check.

YMMV

[brokencase]

Ed, I do not believe the ABS has a keep alive memory. In fact, as I look at the EVTM it appears that the ABS module only gets power when the key is turned on. Unless I have missed something. Please verify this.

This is a surprise actually. You would think that the ABS computer might need some long term memory.

I think this is because the ABS algorithm is probably very simplistic...no, let me correct that...it is elegant. It is only looking at relative differences in the rotation speed of the wheels during braking. It does not matter if you change overall diameters of the tires or anything like that.

There is nothing the ABS algorithm needs to "learn" and therefore store in long term memory. It means the engineers fully understood the nature of the problem they were challenged with. As a former embedded software engineer, all I can say is this is the type of code that I admire.

As soon as you start storing calibration information, you run into the problem of verifying that calibration information.

[andyofcolumbusmerkur]

I am always willing to confront any incorrectness in my posts. Are you?
Maybe you were wrong. Maybe you saw that youtube video and mistakenly thought that it was the final word on the subject.
Would you be humble enough to admit to that?

I am trying to understand how your mind works. You have a very rigid way of thinking. You have some good automotive knowledge and skills like how you mentioned to check the alternator for a parasitic drain. Not to many people would think to check that. When someone reads a general statement written in a single post on a single web forum thread it doesn't have much context surrounding it. So if I put myself in your shoes, and I imagine I am speaking to Ed directly and not the entire web community. And he is standing there next to his Scorpio which has a very small parasitic drain with his Harbor Freight multimeter in hand. I can see a statement like "you won't measure anything with the probes like that" making more sense. OR say "Placing the probes across it won't measure anything. Unless it is a blown fuse" again you mean in Ed's case trying to find a parasitic drain. OR say "The only way to do it is as I described previously" which in Ed's case he doesn't have an acceptable multimeter or clamp meter or a IR gun or an Amp Hound to use and is limited to the old school method. Or "But if you are curious to know what circuits are contributing to the drain you can't do this without pulling fuses" again in Ed's case. You sort of remind me of my old boss. He would drive people crazy. And if you asked him he would tell you yes Andy is wrong about stuff all the time!

[brokencase]

I am trying to understand how your mind works. You have a very rigid way of thinking. You have some good automotive knowledge and skills like how you mentioned to check the alternator for a parasitic drain. Not to many people would think to check that. When someone reads a general statement written in a single post on a single web forum thread it doesn't have much context surrounding it. So if I put myself in your shoes, and I imagine I am speaking to Ed directly and not the entire web community. And he is standing there next to his Scorpio which has a very small parasitic drain with his Harbor Freight multimeter in hand. I can see a statement like "you won't measure anything with the probes like that" making more sense. OR say "Placing the probes across it won't measure anything. Unless it is a blown fuse" again you mean in Ed's case trying to find a parasitic drain. OR say "The only way to do it is as I described previously" which in Ed's case he doesn't have an acceptable multimeter or clamp meter or a IR gun or an Amp Hound to use and is limited to the old school method. Or "But if you are curious to know what circuits are contributing to the drain you can't do this without pulling fuses" again in Ed's case. You sort of remind me of my old boss. He would drive people crazy. And if you asked him he would tell you yes Andy is wrong about stuff all the time!

I guess it is about context. I was automatically in the mode of thinking about small currents upon reading Brad's initial post. You know, I have measured the drain previously, not only on my current Scorpio but also on my previous Scorpio. I was thinking about what tiny currents could develop over the years in the aging electronics that might make a Scorpio kill a battery in 2 weeks versus 3 weeks. In my mind that would be like an additional leakage of around another 10-15 milliamps.

But I also knew from long experience (and Engineering training) that you could not accurately measure small currents by measuring voltage drop across the fuse (with a conventional DMM). It seemed very absurd that Ed was trying to to put the probes across the fuse to measure anything meaningful.

I did not have look in the fuse current table to learn discover any of this - I just used that to demonstrate. I knew that my meter could not read less than 0.1 millivolt. But I admit I did check to see if the high end Flukes could read less than 0.1 millivolt. I figured Mr. Humble might have had a really good meter. But he did not.

If I had not provided a rebuttal to your initial post of Mr. Humble Mechanics video, Brad or Ed (or someone else) might have gotten the wrong impression that they could track down small leakage currents using that method. They might have wasted a lot of time fumbling around with their Harbor Freight meters and gotten nowhere.

Now, if you had qualified it, and you said something like "Hey, look at this video... you can measure large parasitic drains by measuring voltage drop across the fuses, but it won't work for trying to figure out why a Scorpio kills the battery in 2 weeks"...then that would have been OK. But you didn't, and that suggested to me that you also did not know that the method would not work for small drains.

But it is not to say the voltage drop method is without merit. Mr Humble Mechanic was able to find, what was it, a 1 amp draw with some bad stereo component? If I ever run into that kind of situation I will attempt that method. It is "new to me". To be honest I was aware of the top contacts on the fuses, but for me they were just there to check for a blown fuse or to check if 12 volts was getting to the fuse.

But that method is for something that kills the battery in hours - like "Hey - I smell something burning" or "Gee whizz - the hatch light is stuck on" or something like that.. From my perspective, that was out of context.

[Ed Lijewski]

So to sum up the discussion here for Brad, and for Dean (AGMs):

https://www.theglobeandmail.com/drive/m ... y-battery/

YMMV

[brokencase]

I like the idea of the solar battery maintainer permanently mounted in the rear deck lid of the Scorpio and wired in to the rear cigarette lighter.

https://www.ebay.com/itm/232553018338

[Ed Lijewski]

I like the idea of the solar battery maintainer permanently mounted in the rear deck lid of the Scorpio and wired in to the rear cigarette lighter.

https://www.ebay.com/itm/232553018338

That solar charger seems to be a trickle charger apparently without a chip to monitor the battery and charging rate, no shut off/float mode, and no desulphation capability.

My cars are either under car covers or in the garage, each on battery maintainers when not in use.

YMMV

[DPDISXR4Ti]

BTW, I haven't forgotten about this thread. Just no time to work on this lately with several other more pressing projects.

Carry on, I'm not ignoring you.

[Ed Lijewski]

This thread already wrapped up Batman (my post above).

P.S. The Scorpio is such a smooth glider. Just ~1600 rpm sailing on smooth asphalt @~45-50 mph in 4th gear. Its alternator is churning out electrons, but far from its potential at higher cruising mph. For fully recharging a battery that sat for say 3 weeks a sustained Interstate 70 mph is needed to free that potential.

In effect the Scorpio trades higher alternator rpms for nice/smooth engine rpms with its 4 speed trans.

So just drive it. Often. And enjoy the glide. Often.

YMMV