Voltage Drop, Do We Really Need To Know It!?

We always here about voltage drop in the classes we go to but does it ever really apply to fixing cars? It is always taught but never really shown in real life examples. Well any one who watches my channel knows I have shown in several videos why it is so important and how to use your meter to see the "pressure" difference between two points. Hear yet again is another example.
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Due to factors beyond the control of South Main Auto Repair, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. South Main Auto Repair assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. South Main Auto Repair recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of South Main Auto Repair, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained.

[@nickmayo2974]

Also, my 6 year old son loves your videos, I'm glad you keep it family friendly :) "Is that what you do at your work Daddy?" "Yep, sure is bud".

[@joeynobody1138]

😂

[@wyattoneable]

As basic as this seems it's still a great reminder of how to check for a voltage drop. There are guys like me who need to be reminded once in a while because we lack day to day experience. Thanks again for taking the time to teach.

[@throttletherapy9998]

Sooo true,me included

[@SmittySmithsonite]

I usually forget to do this because I'm in a hurry, especially when the problem is obvious like the terminals on this one. It should be the first thing I do, in addition to checking battery state of charge.

[@naquoashuey2794]

Spot on! I rarely do voltage drop. It’s a good test and CJDR recommends that over ohms testing. I generally load test and/or ohm test my circuits. I should do more voltage drop testing.

[@cohenjadiel9558]

I guess im asking randomly but does any of you know a way to log back into an instagram account? I somehow lost the account password. I would love any tricks you can give me.

[@chaimjude9800]

@Cohen Jadiel Instablaster =)

[@ianfahlman-morgan2081]

One of the best KZbin channels ever. I've been watching older videos back-to-back all afternoon 👍

[@FortyTwoAnswerToEverything]

Not "one of",..."The best" channel.

[@ianfahlman-morgan2081]

@@FortyTwoAnswerToEverything I stand corrected 😉

[@robertsise7898]

I concur.

[@BigDaddy_MRI]

Ian Fahlman-Morgan Me too. It’s like a very satisfying “This how you do it” drug. 😂😂😂😂

[@ianfahlman-morgan2081]

@@BigDaddy_MRI exactly! I diy all my volvo "projects" and Eric does a great job of confirming my suspicions when diagnosing

[@GeneralRELee]

Eric. O would make a awesome Auto Tech class instructor.

[@sully3010]

I was just thinking the same thing.

[@mykline1]

Can't believe who ever put the new batteries in didn't clean the connections. Rule number one. Was taught that back in 1969 when going through mechanics school. You have to have clean connections throughout electrical systems.

[@jkbrown5496]

Why run down a 200 mV voltage drop? Because at a modest 60 amp draw from the alternator that's 12 watts of heat on that battery post. 0.2v doesn't sound like much until you apply the current. That's like a 1 amp bulb feeding heat right into the battery plates.

[@hethaerto1]

Very true. Also the heat exacerbates the corrosion development and wiring degradation.

[@kyhomegarage3430]

Thank you Eric for all time and effort you put in your channel. Truly outstanding work. Cheers👍

[@HUBBABUBBADOOPYDOOP]

Be it a liquid, gas, photons or electrons- you can't find a leak until it's under pressure.

[@CubasAutomotive]

You can definitely hear the difference in cranking after just cleaning the one terminal & cable.

[@SouthMainAuto]

Back to the basics :)

[@EvanT1995]

I'm in an automotive electrical fundamentals class in college right now and it's nice to see what we're learning being practiced on an actual vehicle! Thanks!!

[@Peugot905]

Watch scanner danner, he is the electrical GOD! I'm subscribed to his premium channel and it's packed with years worth of info.

[@3347861]

Found a lot of problems over the years using voltage drop. Important to note that it will only show up when the circuit is under load. Once again, great video Eric. Thank you!

[@Ed-ip2sg]

This is twice this video has fixed my car. Great explanation of voltage drop.

[@severomendez6889]

Thank you for making videos with electrical testing and repair. I started the automotive service program at my local community college and I am having difficulty understanding it and it frustrates me and makes me want to quit and go back to warehouse work. Watching your videos are extremely helpful, encouraging, and makes me feel at ease that I have a resource for extra information. Thank you, I really appreciate all of the videos!

[@moviejose3249]

Stay with it Severo it takes a good teacher sometimes and you may have to do your own digging on youtube to find one.

[@neverstoplearning382]

Do not give up. It used to be my weakest skill too. With a lot of effort and learning from pros like. Mr O, now I can diagnose with a lot more confidence and getting good results.

[@Lake_Lover]

Eric - Wonderful video! I learned this a long time ago when I was in the Navy in Electronics classes. Folks - understanding voltage drops is essential to your basic knowledge in my opinion. I had this very thing happen to me Memorial Day at the lake. Went to get the truck to recover the boat and it wouldn't start. Mt voltage drop was actually the ground connection on the driver's side head. Removed the bolt put it back in - whola truck cranks and starts. I used a Fluke 77 multimeter to troubleshoot. Having that meter and voltage drop knowledge has saved me lots of money and helped me fix lots of problems. Stay safe out there !

[@Viper81766]

Amen brother :-)

[@Viper81766]

And thank you for your service 😀

[@Lake_Lover]

@@Viper81766 thank you Robert.

[@Viper81766]

@@Lake_Lover In 2013-14 I took two semesters at a local community college in automotive electrical and engine performance . Our teacher was a 69 year old gentlemen who served 22 years in the Air Force and 20 more years teaching electrical classes . Best teacher I had in all my years . Sadly most younger men could care less about learning this field . Very challenging and rewarding if we apply our selves to it .

[@Lake_Lover]

@@Viper81766 Wonderful ! Like I mentioned earlier I took several electronic courses in the Navy graduating an working on top secret avionics. From there, I got bit by the computer bug back in the late 80's and early 90's. For the last 26 plus years I've been doing IT work - now at a community college in east central Illinois. My father/brother and I are all mechanically inclined too. I'm very intrigued by the marrying of auto mechanics and computers in cars managing engine and other car functions. I've been subscribed to Eric's channel for a while now having watched every video he's produced. The first being the AC repair on a 02' Taurus. The first video's that I watched that had electrical/electronic troubleshooting in them really had me thinking the Eric had been in the service and went through electronic school. About the time I was going to ask him during a "what's up Wednesday" someone else had already asked and he has not been in the service. His approach and reasoning skills are so much like mine it's scary ! LOL.

[@NoWr2Run]

It's DAMN SAD that somebody put new batteries & left those terminals like that. JUST PLAIN LAZY IF YOU ASK ME, THANKS ERIC, VERY EDUCATIONAL AS ALWAYS. Hey you do have a remote starter, NICE, I have one from the 80"s, very nice to have, you don't have to keep running in & out to start the vehicle. As I said in an earlier vid. YOUR'E LIKE BATMAN WITH ALL THOSE WONDERFUL TOY'S.

[@billsmith2212]

Not lazy , STUPID IDIOT !

[@63256325N]

I'm surprised people question your methods, your approach is perfect! I was going to say something more but am in the middle of a huge brain fart, so you'll excuse me if I just add thanks for the video and good job as usual! I will say though, I always liked starting with the hardest first so I can ramp into easy as the day progressed..... I can't believe they went through all those steps of replacing batteries and starter and didn't clean the terminals, are they brain dead?

[@billsmith2212]

If a shop did that , I wouldn't let him clean a toilet !

[@workingraveyard]

All the customer had to do was replace the alternator too and he would of had the trifecta. Good example to diagnose a problem before throwing parts at it.

[@bradcampbell7253]

well at 250K miles.....battery and starter can be justified in replacement. but not as a diagnostic method.

[@rgebes222]

This is good timing, my college physics 2 class is all about electricity and circuit diagrams this semester. It's cool to learn all the theory but even better to see how it applies. These videos have actually helped quite a bit in class as well as fixing my old f150, which I think is pretty cool. Keep em comin!

[@renyn21]

These videos are a gold mine for the guy that cares about his car and would like to work on it himself. Thanks for making them Mr. O.

[@johnboomer8468]

Thanks for sharing real voltage drop testing diagnosing. Your passion for fixing vehicles is awesome !

[@Rockardo_]

I’m currently learning voltage drop at my training for my dealership and this is such a great way for me to see a real world scenario

[@chrisb3017]

Been a subscriber over a year, still can't believe you give this away. Thank you

[@actionsmitty]

Free tip Tuesday on a Sunday. I always spray the battery terminals of all my vehicles, atv’s, snowmobiles etc with fluid film when they are new. I live deep in the rust belt and it prevents corrosion from forming. I also spray all ground connections on the vehicle as well. Fluid film creeps into the connection and the cable strands and does a great job preventing problems. When working on someone else’s vehicle I make sure the connections are surgically clean then spray them.

[@zReignYT]

You're a great teacher. I just learned how to properly do a voltage drop test and what to look out for in your videos. And learned a whole lot more. My learning has been excelled from your channel. Amazing work. And amazing craftsmanship. Thank you!

[@SmittySmithsonite]

Great demonstration here, Eric. A prime example of how voltage drop can affect any circuit. A high-amp draw circuit was the PERFECT example. What a difference in cranking RPM after ward! Could clearly hear the difference, even through the camera, across the internet, and through my speakers here. Was great to see the numbers vs. the cranking sound! 👍👍 My very first foray into this realm was with my aftermarket under-dash A/C system in my '72 El Camino, in the 110°F summer heat of Phoenix, AZ. The off/low/high switch I noticed was SUPER hot, when my finger got behind the Bakelite knob and touched the metal behind it. I could smell something burning, and the fans were real slow on high, too. Had a 5+ V drop across the switch! Wire connections were good, though - it needed a new switch (or, I could've disassembled it and cleaned inside it ... but it was all sloppy anyway). Installed the new one, and the fans blew stronger than ever. It's nice feeling 65° air when it's 114°F outside. 😁

[@eyesalooking]

Most thorough voltage drop test I have seen on internet that I have seen. I watched the video to the end. I learned a lot. Thanks.

[@nateottensman3040]

Please do more voltage drop and electrical videos! As someone who is trying to grasp electrical diagnosis I’ve been trying to soak up all knowledge I can including going to training seminars, AVI training videos etc. when you do the diagnostic videos it helps me understand what to do and what not to do so something does not go wrong. Thanks Eric!

[@livewire6925]

Very good info for both the pros and DYI's because understanding the DC characteristics of a car circuits is usually not well known to most wrenches and can be the hardest symptom to chase down. Your explanation was very good. Dirty connections are man's worst enemy. Thanks again.

[@davidduran1877]

Currently learning this in class. Was having a hard time understanding voltage drop but after watching your video, I have a way better understanding of how the test works. Love your videos and keep up the good work.

[@SilverSergeant]

Nice job of explaining voltage drop and multimeter use....great job!! In addition, it shows how pretty simple preventative maintenance can prevent major issues......

[@scottstauffer1201]

I’m taking my first year heavy duty apprenticeship technical training and this video cleared up what they are trying to teach and this helped a lot with understanding voltage drop

[@spelunkerd]

What surprised me most about relearning ohm's law was the hyperbolic shape of the current/resistance curve for a fixed voltage. Effectively that means a nearly vertical downward slope for low resistance circuits that rely on high current. So, those high current circuits suffer a HUGE compromise of power delivery from even an ohm or two of corrosion. Minor circuits don't even notice a little extra corrosion, they work on the flat part of the graph where you need a big change in resistance to have any effect on power delivery.

[@russlehman2070]

Resistance is critical for automotive circuits. With just 12 volts (or 14 or so with engine running), you need 10 times as much current for a given amount of power as you would for 120 volt household electricity. That means anything that draws a significant amount of power has low resistance, and will only work if the wiring supplying it has very low resistance.

[@372nww]

Very informative. Ive always been interested in how voltage drop works in a practical situation and your explanation was perfect

[@cassiuspuckett8789]

Oooo!!! Nice lesson, Erick!!! I wouldn't have thought voltage drop from center of post to battery clamp would be that significant, but you just proved it is. Lesson learned is a clean battery post and clamp are a must to get proper voltage to the user item ( aka starter). Thanks for sharing Erick.....

[@coycarlson4979]

All the stuff South Main Auto demonstrates / teaches is GREAT STUFF 👍😊 YOU have many , many years of PROVEN EXPERIENCE and vehicle repair knowledge and when I watch you make repairs and you say - if I can do it - you can do it - I'm STOKED 😊 Again - GREAT INSTRUCTION , I learn something from every video you make - MANY , MANY THANKS and , no doubt , if I lived near you - I would surely bring my vehicles to your shop for repair and ABSOLUTELY REST ASSURED - knowing you would repair it properly. ✌️✌️✌️

[@mikefedele4521]

I'm with you. I use the same technique as you do.... Numbers don't lie. "jumper cables" are an in the field thing done that too. I think you did an excellent job of breaking it down makes it understandable.

[@SteveB647]

Great practical example of the effects of voltage drop. Thanks for taking the time to explain it so well.

[@nemanjadzombic6101]

You should work out, then work your way in. I don't know other way to find VD, but this works every time. Hey Eric, I'm glad I finally joined the club. I wasn't able to folow your videos for two long years because of my poor English, but now when that improves I know all the effort I had put into language learning, now pays off. Ivan, Paul and You are my main seminars and training sources. Although I'm professional I would be nowhere without you guys and have still much to learn. Greetings from Serbia :)

[@robinsonsmotorcycleandauto3929]

Great video as always and a good reminder of checking voltage drop on any circuit thats not operating as designed.

[@scowell]

Yay! Electrical secrets... one thing most mechanics have problems with. Ohm's Law: E=IR, or volts = amps x ohms. The more resistance, the more the voltage drops. P=EI... watts = volts x amps. Watts is what heats the connection. A volt-ohmmeter is one of the most useful things you can own.

[@Lake_Lover]

totally agree !

[@paulert23]

in what country is E the symbol for voltage?

[@skee0310]

Ever country... that is how it is representative in ohms law, Voltage is E for Energy. Use E or V whichever works for you. 👍

[@tpodell140]

@@skee0310 Voltage and energy are different - the E comes from "emf" - electromotive force

[@colonsmoke]

@@skee0310 E actually stands for "Electromotive Force" as is measured in Volts. Energy is power over time and measured in Watt Hours.

[@rockiemountin7535]

Best auto diagnostics channel on KZbin Thanks Eric👍

[@rnreajr9184]

I had what I thought was a bad starter. The battery clamps and posts looked good. But it wouldn't crank. If I had checked the voltage drop between the battery post and the terminal I would have found the problem. But like Eric said, it's better to be lucky than good. The corrosion was nearly invisible, but after cleaning the post and clamp everything worked perfectly. It'd videos like this one that made me a subscriber. Way to go Eric O!

[@ronbercan1000]

Great video. Thank you Eric. Measuring the temperature is a great ideal.

[@chrisbamford2196]

Thank you, this is the type of thing I try to tell people who want to know. You tell it very well. I'm going to use some of your expressions to improve my description.

[@hethaerto1]

My favorite video so far. I was not aware of this voltage drop method. Thanks!

[@rsanchez5676]

Very well explained. Love voltage drop for parasitic draw testing across fuses.

[@JoesAutoElectric]

Nice brother! Toward the beginning of the video I caught a glimpse of that crust and thought it can't be that easy lol. This is a great explanation of the correct way to do voltage drop testing and you honestly have a fantastic ability to get your point across in a way that is easy to understand. Too many guys neglect this testing. Awesome bro!

[@BigDaddy_MRI]

Just another outstanding video, Eric O. And, inside my head, the puzzle pieces make total sense. Thanks and please don’t stop. These videos are just like master mechanics classes. You da best!!!

[@procharger94]

Your channel is unbelievable. Thanks for all your effort and knowledge with these videos.

[@haywardsautomotive6156]

Nice voltage drop video. Understanding voltage drop, loaded circuit testing, etc is key to be efficient at diagnosing electrical issues. I wish we'd have learned voltage drop testing when I went to BOCES but didn't learn it until later and when I did it made diagnosing electrical issues so much easier and efficient. Understanding your test equipment & electrical fundamentals can't be overemphasized and like you said voltage drop at each connection may be small but when you combine the total drop it may become significant with multiple wire connections. Great video as usual and you are cranking out the videos...pretty impressive!!

[@josephwash109]

If the "other guy" diagnosed it, he would have just said "Take it to SMA and have him install a new PCM."

[@simplemangarage6678]

I've always been more prone to ohm testing a cable/connection vs volt drop. I would have been interested in seeing the resistance difference in before and after compared to your voltage drop test results. I do understand though that a circuit can show low resistance but not be capable of carrying a load or have voltage drop. Or both. Good video. Enjoy your veterans day weekend.

[@BLACKSSG85]

"This is where the pixies start." I smell an AvE subscriber.

[@JohnQLamb]

BLACKSSG85 Release the shmoo!

[@CarsSimplified]

Just here to give this comment thread a poke to get it choochin'.

[@greatnortherntroll6841]

I was watching the Bad Obsession Motor sports channel (from England) the other day, and danged if they didn't reference those same pixies! AvE's evil influence is spreading globally! Lol P.S. Should we tell Eric O that he's fairly Skookum?

[@Leroys_Stuff]

Me too where the focus you fack

[@tboneproductions2453]

Best video on voltage drop in action on the Internet. Thanks so much

[@harleyarcher6732]

#566 belive it or not I am learning new things every time I watch your videos . Don't change and keep your feet grounded

[@leightonwhisenhunt13]

I would love your input, my ex wife has a 2002 Jeep Liberty with a 3.7, on cold starts you have to crank it about 2-3 times before it eventually starts. I replaced the fuelpump, has great spark and fuel pressure. When it's warm, it starts right up. I've worked on cars all my life and I can't seem to figure this out. Any help is appreciated. Thank you. You are hands down THE BEST mechanic I've seen so far on KZbin.

[@erichagler7842]

this is a great video as many have stated this is one of those misunderstood test but, as you can see it is one of best tips and tricks that you should have in your box of knowledge ..... learn it live it . it could save your butt on many jobs load potential is a great bit of the problems on most all new cars or should i say the lack of load potential.....

[@viebien79]

Awesome video! Need to go out to the garage and do some of these tests. Thanks for the info!

[@donburky6777]

As a new subscriber and a A.S.E. diesel d&r certified tech. I love the diesel tips, because even I forget the simple stuff. At the beginning my first diagnosis was a bad ground, thinking that it was a rusty frame. I've seen worse terminals on big trucks, but wow that was a lot of crud.

[@johndemoss2969]

I am retired and 71 years old. I'm teaching myself to do Auto Electrical. I have watched a lot of Electrical Videos on KZbin. But Eric O is the best teacher that I have seen on here. Learning Voltage Drop is so important. What a great channel to watch !!

[@maureenpye9252]

U should be teaching your way of explaining is the best I have seen í am an older tech in nz re training to keep up b the influence of having a family support you is great to see keep on trucking thanks for another awesome video

[@PCDoctorUSA]

Fantastic information. Definitely saving this episode.

[@TheAdam212121]

I love your way of explaining your approach. Clear and to the point. I also appreciate you using a diagram. Great work! Subscribed and liked!

[@chairmankim9628]

Your advice saved me a $1000 repair on my corvette. Thankyou.

[@DependableAutoTruck]

these reminders are so good glad you took the time to show

[@mikecont9742]

Really like these diagnosis and voltage drop/ parasitic draw videos. You have the best videos put there.....

[@alexandriabowe]

Eric O love your process using the basics, you slow down to go fast.

[@baxrok2.]

Outstanding content here Eric. Loved it. I hope people appreciate the diagnostic gold in this video. Thanks Dr. O! BTW, on the Vantage Pro, as long as the voltage range box is highlighted, there is no need to press the Yes button, just use the up down buttons to change the range. Saves a bit of time.

[@SouthMainAuto]

Thanks for the free tip friday :)

[@colinpalmer5564]

Great practical video. Great understanding of ohms law..thank you for the pleasure that watching your videos brings. Keep on keeping on Eric..thanks

[@neverstoplearning382]

Thank you very much for taking the time and explain every single detail. Much appreciated. Master class, no question about it. Best regards.

[@mikebidus7166]

Sir, You are an awesome teacher. No ifs and or buts. Just awesome.

[@dennismarble3591]

Another great job explaining voltage drop testing. Keep making these videos!

[@windycityben4850]

Great video man! Can’t forget those basics! I’ve only had to do a handful of voltage drop tests while I was at the dealer, but they saved my butt every time. Anyway another great video, look forward to your next. By the way you would make a great instructor.

[@gregeconomeier1476]

Great explanation of voltage drop. Now I feel the need to check my vehicles.

[@febbral]

Excellent video on explaining voltage drop across to electrical points in circuit.

[@ArmstrongRacing]

What great timing. My race car was running fine all day on Saturday until my 4th run, then it was dead....wouldn’t crank. Opened the battery box and found crustiest on both posts! Cleaned it up and haven’t had another issue

[@rhkips]

And with that, Eric O. dropped the voltage and walked off the stage! Awesome video, and great examples! For as often as this gets drilled into our heads, it's not often in the real world we get to use it.

[@lucastheriault2787]

Just subbed your videos are a wealth of knowledge. I just picked up an 07 nbs silverado and I got it dirt cheap has been to several shops with no improvement for the previous owner no communication between any modules with blue driver scan tool drove it home with only 1st 2nd 3rd gear it slammed every gear when shifting, terminating resistor checked out at 120 ohm I was at a loss ended up pulling both fuses for the abs and got communication back with all modules except the abs module of course but when I put the fuses back in I got communication with the abs module but I get codes for all the wheel speed sensor circuits I'm at a loss now I have to check all the wires I guess before I condemn the abs module itself still doing research for that.

[@leonardodavinci303]

Unbelievable!! New batteries, new starter and the problem was VISIBLE green crusties, Great video Eric.

[@andrewcole9605]

You're the best and troubleshooting electrical electronic issue I feel like I was in class listening to my teacher terminology uses PD.

[@toddnelson2182]

Awesome explanation on voltage drop. Thanks as always.

[@mid-thumbautomotive7643]

Got a little nervous when I caught the title of the video. Found many a bad connection using nothing more than a volt meter. Good information. Thanks for posting.

[@docoski5518]

That’s what I’m talking about! Good job Mr. O!!

[@iWatchVideosAtHome]

Hi Eric, I love watching your videos. I started working on cars for a living 7 months ago. You have the best car repair channel on KZbin by far, and I cannot imagine how much time it takes to edit and record everything you do on top of regular work. I was wondering if you have any videos repairing an exhaust leak on a GM truck with the 5.3/6.0/8.1 with broken manifold bolts? I have an 8.1 liter and the bolt that broke is on the driver's side closest to the firewall, of course.. I can't figure out how to search through your videos for some reason. Thanks

[@jeremyproctor9671]

Thank you eric I like how you made it completely easy to understand !

[@4ikemir]

Just want to say thank you for sharing your knowledge. God bless you

[@danielwoodhouse1870]

Really good explanation thanks! Especially good for me as I am doing an apprenticeship and this was a good video to learn voltage drop from.

[@ianmacgillivray2740]

That was one of my favourite SMA videos. You really packed a lot of good stuff in there for us diy'ers. Might have been kinda neat, to see the difference in temperatures on that battery connection (using your heat-seeking radar gun) lol!! Thanks.

[@reinhardeder1829]

I like the way you explain voltage drop in kind a pressure ,....very good

[@andrewkirwin6629]

Thanks for all your work Eric ,I’m learning so much from your vlogging

[@1977jelliott]

Top vid! Voltage drop tests are sooooooo important.

[@JoeCdaYT]

I work in the Refrigeration industry and work on my own vehicles. Did just this recently on one of my Ice boxes. Checking the time clock for continuity while it was still connected to the wall. Pulled the neutral wire to the timer motor and connected the meter in voltage between the neutral and the terminal on the time clock. Had voltage and I knew that the clock was still operating short of a mechanical binding in the clock. If there was no voltage then I would know there is a bad time clock winding. Another example of voltage drop in application. My final outcome on this box was the defrost wire was disconnected at a connection point. Thus causing the cooling coil to turn into an ice block.

[@davidbrown1037]

When I bought my brand new 1994 GMC 6.5 Diesel Suburban, 25 Years ago, about 1 year later, I had a slow crank "problem" that was developing. Like this Diesel Dodge, it too has 2 -12 volt batteries and an inter connection. I am surprised that ANY manufacturer would make a connection under the battery cable clamp clamping bolt.... just asking for trouble. GM connected the Positive Posts on the side terminal batteries together on the Left Battery Positive Post with a slightly longer bolt. Even though the Side Post batteries are quite a bit less suceptible to acid corrosion, I found that the bolt did not provide a lot of clamping force and some "Fretting Corrosion" (black areas) had built up. I installed an insulated 3/8" NF Marine Stud Connection on each inner fender within about 8" from each battery, made up a new crimped and soldered inter-connect cable and moved ALL positive connections to these terminals. New clean connections with silicone grease and torqued to about 30 Ft Pounds, then new short positive battery cables. Each Negative Connection went directly to the engine block with a smaller gauge wire to the body. The engine also has a bradded cable to the frame rail. 24 Years and 420,000 Kms later these connections are still good and the truck is going strong. I also agree...... who in their right mind installed 2 new batteries without cleaning these connections. GREAT LESSON IN BASICS!

[@robertsise7898]

Eric, there is no question you have the knowlege here. I think you could easily be a shop teacher and instruct others as well. I realize you are doing just that with these videos, but I am specifically talking about classroom instruction at a technical school. Great video. Thanks for the time.

[@jerrellstrawn6409]

Of the 12,415 voltage drop videos on KZbin, this is the best.

[@richardcranium5839]

great basics. unlike some i have no problem with the title- i totally get it! great using the infared thermometer- they are cheap and a good little comfirmation. easiest way to remember is what you see on the meter is what is not going through the circuit. now scanner danner does his differently , checking battery voltage and then at the circuit. i never liked doing it that way but he does usually get similar results.

[@davidsprocket5141]

Very well done! A resistance on the alternator output cable where it meets the battery positive will cause the alternator regulator circuit to put more voltage on the alternator field to the point that it can't maintain the desired regulated battery voltage and the connection as you showed will get hot, get more resistance and get hotter, loads then start to deplete the battery. A vehicle battery is only to start the engine, the vehicle runs on the alternator. Gotta love it.

[@cruze1953]

That's only true if the alternator has remote voltage sensing for regulation such as the #2 terminal on the DelcoRemy's

[@erikkirby4534]

Great video as always Mr. O! That dodge makes me remember the time i rebuilt one.... Man the head is heavy!!!! So is the crankshaft!!!!

[@nickayivor8432]

Good Morning South Main Auto Repair Very KNOWLEDGEABLE Thanks 👍 From Nick Ayivor from London England UK 🇬🇧

[@davidkroth]

I vote for bonus footage on all future episodes of SMA....