Battery Dead? Won't hold a charge? CAR WIZARD shows how to isolate the problem. Can save you $$$

Batteries that won't hold their charge can be infuriating to find. Let the CAR WIZARD 🧙‍♂️ show you a few tricks to help you isolate the problem.
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[@electrofreak0]

To be clear, when the wizard says he doesn't care when a customer says they checked something, the key to remember here is that you mostly likely don't have a multi-thousand-dollar battery tester at home so your test is less reliable and trustworthy than the tools that he has on hand. That's the whole point of bringing something to a shop, they can afford better testing equipment, and have prior experience with most car issues.

[@jamesgaines6468]

Also a good mechanic can do the same test as a you, even if you do it completely right, and get a hint or clue as to what is wrong that you completely missed because you don’t have years of experience in the field.

[@rockyhill9965]

Yes. Myself and some others have had those times where if we took car to a good mechanic to begin with we would have saved money and time getting the problem fixed.

[@garyr7027]

There's a old school way of testing for a bad battery that many owners don't know. Not rocket science but it works, just depends how bad the battery is. Never assume battery is good AFTER charging it, even a bad one will test good then. Once charged, unhook it and let it sit at the rate it took for it to drain, if it still doesn't start the car then it's no good. Or if it does start it but turns over too slow, it at least has one cell going down.

[@25Nightops]

When troubleshooting anything, never trust the work done before you, always check the easy things first.

[@darryltaylor8995]

😊

[@davecarey7452]

A bad battery can throw you for a loop for sure. You’ve nailed it. Just because the voltage is good doesn’t mean it can provide the capacity or current.

[@captainkirk4514]

Back in the old days we used a hydrometer to test the specific gravity of the battery acid in each cell. If the specific gravity fell below a certain number in one or more of the cells ,the cell, or cells were dead and you replace the battery. But now with all batteries being maintenance free, and sealed, you can't do that anymore. That old school test never failed. In fact, I think I still have that old hydrometer in my tool chest, if I recall, I paid maybe $3 for that tool from the automotive section at our local K-Mart store in the 1970s.

[@grantperkins368]

Yep, no lie, I had one too :-)

[@mikeceli]

@@grantperkins368 I still have mine! Along with a tube of Standard Motor Products "Breaker Point Grease"!

[@grantperkins368]

@@mikeceli hang on to that! Did you find 2 wires soldered to a 5watt globe too? Damn autotype... yes , 12 volt!

[@mikeceli]

@@grantperkins368 No. But I still have the 12 volt test light, I made out of an old screwdriver, old 12 volt mini bulb socket and some old primary wire and an alligator clip. I made that in the late 60's.

[@dj_paultuk7052]

On some cars, the ECU will wake up after the engine is shut off. I.e. Some EU Vauxhall's (GM) do this after 1 hr of power off. The ECU wakes up to do adaptions using data from the last engine run-time. Calculates adaptions, saves, and then powers off again. So in these instances you may see 1amp for a few mins, and then it disappears.

[@Henry_Jones]

I work in IT. Its like finding a network loop back in thr day. You put a continuous ping on and then start unplugging network cables from your switch 1 at a time till the networks back up. That wires your loop and you see where it came from. Usually it was a mini switch wirex wrong or someone plugged 2 ends of the patch cable into 2 wall jacks...once it was from a patch cable that had been run over with an office chairs wheel a bunch of times and the pairs had crossed!

[@kbVACArestatecarsnrvs]

You just don't know how glad I was to see this video come out today! I just purchased a 2005 Lincoln Town Car Signature (like brand new in & out, 64K miles) that is having the same problem. The car only came with a 30 day warranty from the dealer where it was traded in. So that was beginning of April. Before the end of April, the car sat for a couple of days without being started/driven and dead battery. So it went back to the dealer and they put in a new battery. It had a Napa replacement that was about out of warranty, so it wasn't too new. They replaced it with a Delco they had in stock. Well, great for a few days but as soon as I didn't drive it for a couple or few days, it was DEAD again. So I jumped it, started right up. Luckily it didn't strand me anywhere as long as I had driven it that day or the day before. But after a few months now and a couple of non-starts after not being driven, I get a "won't start" if I don't drive it daily. I had an appointment but cancelled it when the dealer said they may have to have it for a couple of days. I know this place, it'll sit out in the packed lot, get banged up, won't be locked up and the last day they have it they'll decide to work on it for it to be ready last minute or another day they'll have to have it. They said they will still not bill me since it's a continued problem from April. Should I bite my teeth, make a new appointment for early in the week (to get it back before a weekend) and hope no scratches, no damage is done to my cream puff, and let them try and solve the problem hoping that they have the machine you just showed us? Wish you were in VA!

[@norisboren5402]

To K B Check that battery cables bolt isn't corroded or loose. Check that all interior lights & everywhere are turned or switching off. 2. REMOVE battery for auto parts IN STORE load machine testing (this testor may charge it 30 min. before doing test). Usually free. 3. Install known good battery. 4. Wait 10 min. for all electric to sleep. Measure amp usage amount at battery cable with Multimeter AMP CLAMP, should not be more than about .025 amp (25 mili amp). If .08 that's too much. If . 02 that's good. One of these can be the problem. Hope helps. Me ASE electricial. Have store write note about battery if bad, date & sign before returning to car sales.

[@kbVACArestatecarsnrvs]

@@norisboren5402 Appreciate that repky. All of that was to be done the 1st Time the dealer had it for the 1st battery swap. I'm about thinking the 2nd (new) one is not a good one. All cables and post connectors are like new and nothing is staying on like lights etc. Only thing that stays on is the small clock on the dash. I don't even leave the auto light switch on anymore I got so paranoid lol. We'll see soon I guess. Just hate taking my cars to some repair facilities but not too many choices out there. Thanks again for the info.

[@philipsgarage]

I got the amp hound in one of your previous videos. It helped me track down a 3amp draw I found that was killing my battery on my ml63. Turned out to be a amazing tool, ended up being my headunit.

[@clover7359]

4:23 I need to add that some vehicles have part time charging systems (common on later Honda models) that intermittently don't put a load on the alternator as a fuel saving measure. This freaked me out the first I checked my Acura TSX's charging system. I measured the voltage at the battery terminals with the engine running and it was at 12.5 volts. I almost had a heart attack because I didn't know about the feature. *It can be defeated by turning the lowbeams on.* Later at home I checked again and it was at 13.4 volts. It was definitely time to replace the alternator because it was 10 years old at the time and had serviced a car driven year round in Fairbanks for 9 of those years. 13.4 volts is usually a sign that the alternator is about to go out and it may already be allowing current to flow out of the battery and causing a parasitic draw from that. Some vehicles run 13.7 volts normally, so under 14.0 isn't a death sentence for the alternator.

[@grantperkins368]

Cheers!

[@theundergroundlairofthesqu9261]

I believe Honda started that to reduce load on a cold engine after it has been started, in its first minute or so of running.

[@buzzcrushtrendkill]

These videos are what I love the most, instructional. Yup, those cheap USB adapters one buys at the gas station...are built cheaply too! I had one that weakened a battery. After finding the USB adapter so hot could only touch long enough to pull it out, felt lucky the car didn't burn.

[@carmudgeon7478]

That little Fluke 115 Wizard used to check voltage can also test up to 10 amps too. It's nice to see those different testing tools at work.👍

[@Mrflash222006]

There a good all around meter had a 115 for years, well worth the money, sent it in for calibration and it hasn’t shifted from spec

[@carmudgeon7478]

@@Mrflash222006 You speak truth. I have an 87 that I sent in every year for certification. It came back for 19 years just recertified, only needing recalibrated in the 20th year when I knocked it off a 988 CAT loader and cracked the + socket. Fluke caught the crack, fixed it and it's working like new all included in the recert price.

[@fluffyblue4006]

Flukes usually have expensive fuses in them. The Snap-on Vantage has a normal automotive fuse, as far as I know. If I had one, I would also use the Vantage instead of the Fluke, when measuring amps in a vehicle.

[@Mrflash222006]

@@fluffyblue4006 tbh flukes are aimed at a different market, anything more than 6-7 amps you move over to an amp clamp tbh

[@entity6966]

@@fluffyblue4006 fluke fuses are pretty cheap. You can get some from Amazon for a decent price

[@ericbmusic]

Was trying to figure out a parasitic drain the day this video was posted; definitely a stroke of serendipity. bought a cheaper model of the Amp Hound on eBay ($40) and immediately pin pointed two unrelated drains. Was about to bring it to the dreaded mechanic. Thanks C.Wiz!

[@bobbishop9339]

For the cheapest test just use a test light to find a drain. Hook the light between the battery cable and the post on the battery. You should get a lite if there is a drain. Then just pull the fuses one by one till the light goes out. There is your drain. Gets kinda confusing if the dome light is on, (you got the door open dummy) block out the door switch. I found the clock was usually the drain. but I have been out of the business for a long time. Anyway good video.

[@27zacmaklea35]

Legend has it: The Car Wizard can successfully divide by zero.

[@timothyharrison8953]

A recently acquired Toyota Sienna van with a four year old battery was giving me fits with an occasional dead battery. The battery tests good at the parts store. Testing for drain I made sure the hood open switch was closed. I placed my multimeter inline and closed and locked the van and waited for about 10 minutes. Eventually the draw was down to 18 milliamps. I replaced the "good" battery and we've not had a dead battery since. Sometimes it's not as easy as it looks.

[@Cheepchipsable]

Yes, you do get marginal batteries that might work most of the time. They are pretty annoying because you don't want to spend the cash for no reason. Since int might start the car in the morning or during the day with no problem, it seems these may pass a test but still be failing.

[@samholdsworth420]

Four years old? those cheap Walmart batteries don't last

[@mediumsizedm]

Batteries last 3-5 years on average

[@sejembalm]

A handy gizmo I bought was a AutoWit portable jump-starter that does not use an internal battery (that slowly goes dead in your trunk), but a capacitor that starts the car with just a quick charge from a weak battery (even your dead battery). No pre-charging required and can be used more than 100,000 times. It is easier to use and has a longer lifespan than traditional battery car jump starters.

[@jaymorgan8017]

Here's another tip - if you have dual batteries you have to disconnect one before you load test.

[@Sonny_McMacsson]

Last time I diagnosed a battery that would die overnight, I charged it fully, put a voltmeter on the posts (not the connectors!) and turned on the headlights. The voltage sagged from about 12.5V to about 9.0V. Obviously the internal resistance was too high so I got a replacement. The store confirmed a bad battery with a tester. I haven't had any trouble since. When I diagnosed a charging problem on a different car, the already too low system voltage would sag when increasing the engine RPM, probably because the ignition coils were consuming more power with increasing spark frequency. I took out the alternator and took it to the store to be checked. Before testing it, the guy snarkily said, "It not the alternator." The tester indicated it was the alternator (I told you). A new one fixed the charging issue.

[@fubartotale3389]

Wow, a New Beetle with electrical probs? NO WAY!

[@theyunglos]

New? lol

[@johnmoore6501]

The Fluke Multimeter the Wizard used to measure the workshop flat battery voltage, It also measures amps {10 Amps I think} You can use that in series with the battery to measure drain,

[@simmonspdx]

Yep. No need for those other meters the Fluke 115 he uses is all that is needed. It measures AC and DC current to 10 A (20 A overload for 30-seconds max). It’s rare to see a multimeter that does not measure current.

[@lkneepkens53]

Thanks for your great vids! Love the way you use your language , very civil, no swearing every two minutes. This vid in particular didn’t learn me much but some others really do. Please continue

[@NoahHeadglitch]

I had a bad battery once at the beginning of college and it took me 6 months and multiple Napa trips just to tell me the battery was just fine even though I knew the battery was bad. Took me going to a shop to tell Napa the battery was bad. Sure enough I got my free warranty battery. Haven't had a problem since. The stupid battery test where they charge it and tell you the battery is good so you don't get your warranty is such a load of bs. Tells you nothing about the condition of it. I'm very happy the wizard made this video to show the right way. 👍

[@ctu5086]

I bought a used car with a good looking aftermarket radio. I adjusted the audio settings to make the sound louder, higher Hz, and associated equalizer settings. I thought wow this stereo system sounds great and just as good as a system with aftermarket speakers and a amplifier. About a couple of weeks later I was stranded with a dead battery. I put two and two together after having to walk a couple miles with a car battery: And I haven't touched the default radio settings two years since then. Never had that problem again.

[@a1ar127]

I have a 2003 Mountaineer that only has 120,000 miles, and for the last half dozen years we use it occasionally as a hauler with the back seats flat. There was some sort of parasitic drain where if it sat for a week or so the battery would go flat. The only clue to the gremlin is a "door ajar" message on the dash. Rather than try to troubleshoot it all, I installed a cutoff switch on the battery terminal, and if it’s going to sit for more than a day or so I’ll disconnect it. Sure, when I reconnect it I need to reset the radio stations but I guess the rest of the electronics aren’t phased by being shut off. For the price of the battery terminal cutoff and minor inconvenience when I need to use the car, the battery stays fine.

[@Oddman1980]

One of the weirdest "electrical drain" issues I have had was on my 2010 Colorado. You could jump it, and it would start right up. You'd shut it off, and it would show a good charge on the battery. But as soon as you tried to start it, it would drop to about two volts. I isolated the battery from the truck, charged it, and it would show 12v again. But as soon as any load was put on it, it's back down to 2V. It wouldn't even illuminate a test light, and when I took it to Autozone to replace it, the battery wouldn't even run their tester. Another weird one I saw was on an Isuzu Trooper (which was a massive, massive piece of shit) where the alternator failed in such a way that it was drawing current off the battery when the vehicle was off. It was also putting some AC current into the battery. A new alternator fixed it right up.

[@marks8068]

The regular Isuzu Trooper wasnt that unreliable, the Turbo-Trooper was the one every shop fears around here. (mostly since about 1 in 5 throws a rod during the yearly emissions torture test) I nearly lost my inspector licence after getting caught not having tested one, I didnt do it since I had to pay for a new (used) engine the year prior when it blew up at 6000rpm

[@wildman510]

I remember reading a story where somebody bought a really nice Mercedes but for some reason randomly the electronics would just totally stop working and you'd have no lights, they then bought another one with a similar issue and after months of research found out that it was caused entirely by a cheap radio that had been swapped in

[@richardsmith2721]

The best way to find shorts is replace your 5A fuses with 30A fuses and look for smoke.

[@stevewhite3424]

I must admit I have been tempted grievously on occasion to do just that but have always resisted it. Lol

[@richardsmith2721]

@@stevewhite3424 I was amped to try it and it was a shocking experience.

[@stevewhite3424]

@@richardsmith2721 😄

[@rossbrough6198]

I have a 2012 Smart and the original 10 year old battery still checks out perfect at every service! Just shows the variability in manufacture - helps that I live in a moderate climate without great hot/cold extremes. Yes, it s tiny car, but it's a tiny battery as well. Great work Wizard.

[@bradklingensmith]

Being from PA ww get used to the cols winters wrecking batteries. Then when I was in the Air Force in TX thats when we learned that heat is just as bad for a battery as a cold PA winter. It is also cool how you bring your techs into the videos. Seems like you have a good family type shop.

[@robertbigler7743]

I liked this Car Wizard video much more than the "tour of the car" videos. I actually learned something today.

[@Rickmakes]

One thing that I have seen cause a lot of problems is dirty terminals. Use a battery brush to clean the clamps and the posts every time you remove and replace the clamps.

[@FWDSUXARSE]

Baking soda and water helps clean them or there's a can of battery terminal cleaner that will turn pink if battery acid is detected / present on the terminals. I use an old retired toothbrush to clean the terminals.

[@Bizija123]

Yes that's a very good tip Wizard. Good battery voltage does not equal a good battery and bad voltage does not equal a bad battery. Load testing while at a full charge is the best test. I have a $40 Top Don load tester that has been pretty good at showing me the health of a battery, certain no where near as accurate as that beast of a tool Magic Mike was using.

[@steveauston6020]

Can also test for a drain with a simple multimeter. No need for a high end device. The battery tester is expensive but an excellent tool. I use mine all the time!

[@Mrflash222006]

Another basic test is to watch the voltage while cranking (flood clear mode) as the current rises the voltage drops anything below 9v will freak out modern electronics

[@leonascherer1617]

I know why you are called the Wizzard. Your knowledge level is so far above most other technicians. Thank you for the lesson.

[@docgiggles130]

Anyone with OnStar in their GM need to keep in mind that OnStar is always drawing power. It can kill a battery in as little as a week. If you are going to park the car for awhile, pull the fuse for the OnStar.

[@jbstepchild]

One has to love how thorough the wizard is just amazing

[@ForTehNguyen]

i have a simple battery load tester at home, its been really useful when i periodically test my batteries to see if a battery is on its way out before it leaves me stranded somewhere

[@patrickduffy3809]

My kid is a lot runner at a Honda dealer. They test the battery on every single car that comes in, usually within a minute of pulling it into the service area

[@samfungccim]

How do you charge the customer when it takes you half a day (4 hours?) to find out the battery is no good when your shop rate is $150 a hour? ($150/hr x 4 hr = $600) You're losing money if you do not have the youtube channel? thanks for showing us all the stuffs about car repair and maintenance!

[@davidedgar2818]

I'm more used to the old school tools before computer modules. I appreciate the up date. Great tools to show off. It helps keep my mind active.

[@scottgfx]

Batteries don't last too long in Florida, but I had an AGM battery that I bought from a chain who's names rhymes with "Oh Really" and it didn't last two years. Battery would recover overnight, but on short trips, it would be close to dead and just barely crank the engine. I skated by for a long time until it finally died. Comparing how it cranks now with a new battery to how it performed for (almost) two years, I think I got a bad battery out of the gate.

[@nelsonbrum8496]

I've used a 1 ohm 10 watt resistor in between the cable and battery, and used a multimeter set to volts to read across the resistor. It gives me current reading in volts. Not gonna blow the fuse in my vintage Fluke 87 regardless of what powers on.

[@yambo59]

This is invaluable testing information for situations like this, I had it happen to me on more than one occasion. in one instance the battery would show a full charge but immediately after it would barely start the car one time with a known good starter and good connections, however a jump battery would start it repeatedly. Of course I didnt have the $$$$ tester shown here so I went to a very good battery retailer in my area and they fully test your charging starting system as well as battery for free using a tester similar to what is show in the video. In less than ten minutes they confirmed a shorted cell and brought me out to show the readout -- I bought a new battery which they also pre-tested before installation just to be thorough, that was two years ago and ive had zero problems since. I recommend anyone, especially anyone who isn't car savvy just take it to a competent trusted shop or battery retailer so they can save you tons of guesswork and aggravation in finding such unusual issues. Just because a battery is new doesnt mean its not defective, mass production almost guarantees a certain amount of defects. On another note, one can also use a quality multi-meter with a reliable milli-amp range to find a draw, once you see the draw as wizard says just pull fuses one by one until the draw drips down to the low milli-amp range, it doesnt take a $$$$$ tester to do this either just use a good quality digital multimeter with a reliable milli-amp range. However finding a shorted cell on todays sealed batteries requires a more sophisticated testing device than most DIY'ers would have.

[@rustyrazor1853]

@9:21 "You really want to have POINT zero two. not POINT TWO!" That's what the cops told me LOLOLOLOLOLOLOLOL

[@webmonkees]

register your used car..with the car maker. Or new car for that matter. Recalls for the 2001 Honda Accord airbag.. is still active. And free. I didn't get to keep the module, the dealer send them off to get paid for the service.. in 2021. I think it may have been replaced under the recall earlier but well, they insisted. and test drove a 2003 5 speed Civic. same paint. who knows, someday they may give me paint.

[@jondoes7836]

Had current draw issues on two of my cars: 1970 GTO - glove compartment light wouldn’t shut off. 2004 Mustang GT - factory Mach amp wouldn’t shut off. Found with amp meter & pulling fuse method as shown by Car Wizard.

[@lyfandeth]

+1 for the Amphound! Much less screwing around pulling fuses.

[@JDMHaze]

aftermarket battery being wired wrong is a common one as well as the USB charge r because some ppl dont know that some cigar lighter power sockets are powered while the car is off

[@Blurky82]

For the simple exclusion of electrical faults you can also use a cheap clamp meter, it doesn't have to be very accurate, if you use the fuse pulling methode you will see a difference in Amps, and yes that also works with DC voltage. Also what Car Wizard didn't tell in this video, if you did some investigation yourself but can't solve the problem, then pass on everything you have found already (for instance which fuse you saw the amp drop when pulled) to the shop you bring it to, it can save a lot of time and (your) money.

[@TheSleepingonit]

One thing to check is the lit up mirror in the passenger side, had that issue once

[@snap_oversteer]

Or a faulty glovebox door latch that makes it lit when closed.

[@lyfandeth]

All of which is why several cars makers kill the power outlets when the ignition is off. But a bluetooth OBD2 diagnostic device, or any device plugged into that port, can draw power ALL the time. That's controlled by the device. FWIW.

[@TheSleepingonit]

My problem is I was driving with the belt off, because of a bad power steering pump and pulley

[@stt9895]

You can also check battery with a regular multimeter if you don't have $10.000 professional equipment. Hook up multimeter to a battery to measure voltage and crank your car at a same time. If voltage goes below 10 V battery is usually bad.

[@ThunderbirdRocket]

Yep 👍🏼 . And watch to see the alternator begin to function bringing the voltage reading up around 13.5 Volts .

[@d1mennis]

2 years ago I had a problem with my 2009 RAM 1500 not starting. The battery was stone cold dead! It would take a charge but in the morning it would be stone cold dead. My 10 amp charger would pop the internal overload trying to charge the battery so I would have to jump it off another car battery to get it to start. I checked all the obvious things that would draw power and nothing. Finally after 3 days of messing with it I got out my amp probe and hooked it up to the battery terminal. It was pulling 0.72 amps just sitting there! I got curious so I started pulling fuses and relays. BINGO! The radio fuse dropped the amperage to 0.05! Great! I wanted a newer radio with GPS anyway so I started taking the dash apart to pull the radio out. Just when I was about to start disconecting the wires I thought let me see if there's a CD in it which ther was so I ejected it out. Guess what! The amperage dropped down to 0.05 again. The CD player was drawing power even though everything was off!! Another time I had purchased a motorcycle battery. It was a sealed gel battery. 3 months later the bike wouldn't start after sitting for 9 hours. Checked it with a multimeter and it read 12.8 volts. Left the meter on it while trying to start it and the meter went to 0 volts. Shut it off it went back to 12.8 volts. If you crossed the terminals not even a spark! Dead cell. They refunded me the money but I had to prove to them that it had a dead cell!

[@ronniemaeker9102]

I have a "prong" type load tester that has a load coil and an old school ammeter bolted inline between the positive and negative. It is easy to read and has no electronics to break. If you have removable caps, you can test and if a cell is bad, you can watch it boil. It is a "one trick pony", but does the trick...

[@matthewdutoit]

I takes my time to diagnose my car was draining the battery. Replaced battery as it's way too old. Still the same... Replaced the alternator brushes... Still the same... Replaced alternator. Still the same..... Found out that the wiring behind the alternator is cut. So I joined it. Voilà. Charging perfectly. Have spare alternator to keep in case. Spent lots of money on it but turned out wiring cut. 🙈

[@lylezink1518]

thank you thank you thank you. I know it is impossible for you to do a super informative video everytime but its videos like this one that makes you the car wizard and why 759,000 people have subscribed!!!!!

[@CarWizard]

Too bad the views are so low on this video.

[@stevewhite3424]

@@CarWizard I think that with the general public and many mechanics when you mention electrical their eyes glaze over. Lol

[@NafanyaZX]

@@CarWizard Thank you for what you do. Though seeing how this is aimed at DIYers, I'm surprised you didn't use the multimeter in amp meter setting hooked up in series via alligator clips. It is the cheapest method to test for parasiitic draw. Personally, I love to see how people in the trade do things on the other side of the pond. Greetings from Germany.

[@kustomdeluxe8489]

Lincoln in the background. Even Oliver Wendall Douglas drives all the way from Hooterville to have the Car Wizard look at his vehicle.

[@hotpuppy1]

Realize that if your car requires a not so common size, the one in the store may have been there for a good year waiting. I worked at Sears in the 80's and we had some really oddball group sizes like for Mercedes Diesel that sat for a LONG time. If a person came in and needed that size, I would bet that it didn't last the warranty period. Look at the date code on the one you buy to make sure it is only a month or two old.

[@phillipsmith1489]

I worked on a BMW motorcycle that kept throwing an ABS fault. Battery was good according to O'Reillys and the bike started and ran just fine otherwise. Still, it was the battery causing the fault. The old, sensitive ABS controller was not happy with the battery. New one made the light go away.

[@blaketindle4703]

I have the very affordable Top Don Battery Tester and it’s worked well for me.

[@floppyseizure8615]

17:18 Magic Mike is staring into your soul.

[@1983dmd]

Here is an opposite situation. The battery in the trunk of my 1985 BMW M635CSi blew up while cranking....Scared me to death !!! After putting a new battery in, I checked the voltage with engine running: 18,5 Volts !!! The alternator was overcharging the battery...Culprit: Bad voltage regulator...

[@pedrorojascervantes3928]

Yikes!!

[@imtheonevanhalen1557]

Took my mom to the airport once in her almost new Chevy Cavalier, zero issues with the car on the drive there. Came out, got in and turned the key.....nothing, zero nada!! Got a jump from a SkyCap ($20 bucks....those guys are parasites...)....drove it to an Auto Zone, got a new battery, and it was fine after that. New batteries do fail..........

[@a7xphenix]

Mercedes’ it’s always the damn seat modules I swear, especially the w203 series

[@MrROTD]

I got the dome light problem on my personal car before , I had to pull the bulb because for some reason it wouldnt shut off ever no matter where where the switch was set. My work has a good tester it shows bad cells internal resistance, if perhaps the battery is good but needs a charge IE the customer takes many short trips or maybe a terminal is loose corroded. So much of my time is taken up by battery issues Im gettting better at diagnosing these problems.

[@jirka87]

Wizzard - maybe its my mistake but i did not heard,that to be able to measure draw correctly you need to wait lets say 20minutes to let ALL the modules go to sleep. And because you need to measure amps in fuse box (very often placed like here or simply somewher IN the car) its best to close the locks (screwdriver) on the OPEN door/doors just to hack the door unit to simulate they are closed. When all modules are sleeping,than you can measure parasitic draw. 0.025.seems little bit low to me,but everything under 0.045Amps is ok

[@pedrorojascervantes3928]

My research says you're about right on the mili ampere thresholds you stated. Modem cars ( anything after 2014) just have so many modules & are very sophisticated. Computer controlled alternators complicate what was a quite straightforward test not long ago!

[@billrobertson2122]

Volt meters are what they are, but they aren't what they aren't. Old fashioned analogy is voltage is like water pressure. You can have 100 PSI of water pressure, but if it's only a tiny stream of water you won't get much total flow (analogous to electrical current). A battery with full voltage but low amperage is like a high pressure stream of water through a tiny tube -- very limited in the work it can do.

[@declanfarber]

Why did you delete the discussion about how to improve the accuracy of a clamp meter in determining current leaks? That was a really good thing for people to get a handle on. It’s not talked about enough.

[@DUDE72341]

THE WIZARD..keep N it real 1 mess at a time. Ya i can turn a wrench , but electrical and diagnostics, dealing with shorts...OH boy..this is good content👍

[@dneedham8302]

Great video Wizard! I just went through this with our 2006 VW Beetle Convertible. In our case it was a USB charger/ Bluetooth transmitter. It never shut off and drained the battery overnight.

[@samholdsworth420]

Get a USB charger from a reputable brand (say anker). You won't have that issue.

[@RDEnduro]

I absolutly love that the tester had a camera and a printer on it.

[@jwelchon2416]

That battery test is amazing. My neighbors bought a new battery from WALMART and in a short time it only read 10 volts on the meter. I assumed it had a dead cell but it would have been nice to have printed evidence for them to take back to WALMART.

[@samholdsworth420]

Walmart takes anything back. Keep the receipt in the glove box

[@jamesfarmer3676]

I had a bad battery in my truck , it 2 years old, had it replaced with new AC Delco, been happy with it, must remember get a new battery not those recycled ones they call new because they just replace the bad cell or refill the low cell, you get what you pay for.

[@joshuawheeler4404]

To find where the draw is you don't need to pull the fuses put your multi meter into millivolts mode and measure across each fuse and you will get 0 or 0.1 on most fuses untill you find the one with the draw and it will have a millivolt reading there is actually a way to calculate to millivolt to fuse rating to get the amount of current that's being pulled through the fuse so really that tool you have is completely not needed

[@ozarkliving7263]

Fluke, the only DMM I use, still using the same one I purchased in engineering college. My Fluke does current too, doesn’t yours? Voltage in parallel, current in serial. Takes me back to freshman year engineering

[@joefaracevideos]

Just leaving the key in the ignition, killed my wife's Subie.

[@anthonyxuereb792]

Imagine your dentist pulling teeth saying "nope, that's not it........" ow ow ow ow

[@JakeTaylor1646]

I got a kick out of this one because this exact thing happened to me one time on my toyota pickup!

[@77zrod46]

Like the wizard said, a cheap carbon pile load tester or a digital tester can do the same as his $1,000 tester. We use a delco-remey digital multi function carbon pile type tester and they are way cheaper.

[@engineerinhickorystripehat]

I am so old , I learned everything there (was) to know about flooded cell batteries from an EE working on the original Midtronics conductance tester .... over the phone.....long distance , toll free..lol. Heady times indeed.

[@ForTehNguyen]

the battery is the most unreliable part of that loop, thats always the first thing to check

[@artfordlowery490]

Thanks Mr wizard 😀 and also magic Mike for sharing this very informative information about batteries and shortage in vehicles its good 👍 advice

[@daveforgot127]

Thanks. Have not driven my Toyota Yaris in 8 months and it won't hold a charge. I am going to a shop on Monday.

[@HypocriticYT]

Ive got a large one with Bakelite case and has a needle that moves left and right. Can test anything with it.

[@rob5944]

My daughter messaged me and during our chat happened to mention that her car was dead that morning and that she was going out to get a new battery. From experience and watching stuff like this, I advised her to go and request a free check of the whole system. Did she? No, but as I said to her, it probably is the battery..... however, time will tell.

[@FatLingon]

Can't one use the multimeter for measuring the amps as it is a MULTI----meter? Anyways, thank you for teaching me this methods of hunting down the draw on my car battery! :)

[@Celician83]

That's the exact same tool we used at the Walmart Auto Care Center I worked at. You'd be surprised how many people told me "I just bought that battery 3 months ago"

[@jynxclover2996]

when i first got my 07 raider, it would drain the battery in two days. come to find out, it was the "aftermarket canbus" adapter for the aftermarket stereo. trashed the radio and the adapter the found a factory radio at my nearby salvage yard and fixed my problem

[@MASS_ONE]

wizard those pumas are fresh

[@funnypranker34]

I’ve also seen bad batteries completely dead shortly after purchase

[@pmkstudios]

Today on Pine Hollow Auto Diagnostics if you want to go down the rabbit hole all the way. Nice video Wizard:)

[@elmecanico4943]

Not everybody can afford that tool, Wizard. I suggest a load tester. Its about $35 at Harbor Freight. It tests the CCA on any battery. It is easy to read and operate as it is analog. The tool itself has a lifetime warrantee. Unless you are pushing people to buy that expensive tool online..

[@matthewhaddon599]

You cannot rely on battery testers sadly....my works van kept failing to start and a professional technician came out to test the battery with a Midtronics tester and the test showed a good battery, but after two visits with the same results, I insisted that the battery be changed and this cured the issue.....the battery was faulty even though the Midtronics unit said it was good!

[@stevewhite3424]

Well you do understand that Midtrronics makes battery testers that retail from a 150 bucks to $3000. There is significant capability difference between the 2. :)

[@pedrorojascervantes3928]

Sometimes the older $30.00 " toaster " element style tester still works better than a simulated electronic load like the one on the cheaper $50.00 & up to $ 300.I have a couple of those kicking around. Frequent use will burn them up but for a shade tree / occasional use they still work fairly accurately .

[@pedrorojascervantes3928]

@@stevewhite3424 Yes! Exactly so.

[@juanmortaco831]

Been waiting ages for this video, thanks!!

[@gregdawson1909]

A great test of the health of your battery if you don't have a load tester is to check voltage with the headlights on engine off. A solid battery will drop voltage slowly, a crap battery even if it appears to take a charge will drop off very fast, 2 headlights are good for 10 amps and figure another 4-5 for all your marker lamps / tail lights.

[@stevewhite3424]

And absolutely great parking lot test! Have used it multiple times over the years.

[@ThunderbirdRocket]

Thanks !!

[@douglasmiller1467]

Learned allot Wizard, thanks much.

[@keithtomlin4649]

One ticnition had a parasitic load could 't figure out right away; final found out the pcm computer was staying at full draw or at least more power than it should with the ignition in the off position.

[@timw8228]

Can I bring in my '84 Cadillac Fleetwood Brougham with a battery drain? I haven't found it yet. It isn't the battery. I had a ding taken out of the drivers door and they removed the door panel. I suspect something there. You'll enjoy getting to the fuse panel. Crimney I need a midget.

[@joseacd01]

I personally had bad luck with auto parts they had told me the battery is not good just to make the sale after i have put the new battery it will still do the same thing in theirs parking lot in front of them