After replacing 3 alternators. Customer said it doesn’t charge !!!!!

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So I was asked this question and didn’t add it because the customer picked up his car after I edited and put this video out. So after I fixed this I asked, if the battery ever died? And remember he just asked about low voltage repair. And he said, it did die but the mom that was there also and brought up that he would leave his lights on at times. As for the initial issue with the first alternator. That I will not know what happened. In this video, I just wanted to explain that the voltage was low but it is normal. It’s not how older cars were back in the day that if anything read under 14 volts you had a bad battery.
Disclaimer:
Due to factors beyond the control of Oz Mechanics, I cannot guarantee against improper use or unauthorized modifications of this information. Oz Mechanics assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. Use this information at your own risk. Oz Mechanics recommends safe practices when working on vehicles and or with tools seen or implied in this video. Due to factors beyond the control of Oz Mechanics, no information contained in this video shall create any expressed 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 from the information contained in this video is the sole responsibility of the user and not Oz Mechanics.

[@OzMechanics]

**Want to own the tools I use ?? Click on the amazon link below to get my top 5 Tools I use** Automotive Test Light- amzn.to/3z1Pdxa Flexible Backprobe- amzn.to/3Pyr3zO Multimeter- amzn.to/3PbuT23 OBD Scan Tool- amzn.to/3zaNWnq Wire Piercing Probe- amzn.to/3OecWhT

[@sergiodjf]

😂 The other shops replaced 3 alternators and couldn’t figure that out. Good job! 👍

[@hiscifi2986]

Looks like they replaced it with an old dusty alternator, three times.

[@harriettedaisy2233]

Had a customer back in the day, replaced alternator, regulator and battery. Battery would still be dead after sitting overnight. When he dropped the car off he left the keys in the glove box. First thing I noticed was the switch for the glove box light was dangling behind the glove box. Turns out the trunk light was always on too.

[@methylbenzodiazepine]

I am a dealer tech. In about 2013 our manufacturer changed the out put of the alternator to keep the battery at about 12v and not much higher. This extends the life of the battery. They said the battery can last an additional 30% or something like that. Keeping the battery at 12v instead of 13 to 14 volts keeps it cooler and extends the life of the plates. Good video, I did not know hyundai did this as well.

[@ScottDLR]

Did they go to AGM batterys?

[@methylbenzodiazepine]

@@ScottDLR some use AGM, but some still used lead acid. Newer use lithium ion. As well we use a new 48 volt lithium ion

[@soundfarm8814]

I know it's been 2 years and I don't know if you'll see this question, but this is happening to me right now. If you don't mind my asking, what manufacturer?

[@methylbenzodiazepine]

@@soundfarm8814 Mercedes Benz

[@DavidGutierrez-zi4dy]

what about is the changing ligth is on in the dashboard?

[@billsmith2212]

Great advice = do your research BEFORE changing parts ! As long as the battery was checked and no parasitic drain it should be fine . Today's JOKE : the customer asked the other shop if they checked for parasitic drain . They told him to " Call a PLUMBER " !

[@riblets1968]

I actually learned something! Thank you. I liked the "let's learn together approach" for this particular problem. You used your experience to lead you--and us--in the right direction and it paid off. Well done, sir!

[@OzMechanics]

Thanks for watching

[@jeffmatson2046]

Thank you for your patience and diligence. Yr tenacity shows great job 👍

[@jwilkers1]

I had a Ford that took me 4 alternators to finally get one that would charge. 2 Aftermarkets 1 Motorcraft (still didn't work) 1 one last aftermarket. I doubted my diagnosis a few times but once we got one with the correct regulator inside it worked like it was new.

[@fastrice3461]

Dang you went above and beyond explaining this one! Thanks! 👍

[@OzMechanics]

I just felt I had to explain piece by piece to really get to the point of this issue

[@ba7tow1776]

Alternators will not charge 14v all the time while running to avoid damaging the battery in certain vehicles. Great work!

[@billrimmer5596]

Had the same thing on a Honda. Smart charging. That system out smarted me

[@OzMechanics]

Yep, that’s the first one that kicked my rear end

[@wyattoneable]

That was pretty cool to see the graph confirm the operation.

[@Codeeze]

This explained a lot for me - thanks for the video sharing the knowledge. I have a Volvo C30 1.6D Drive (Full of eco baloney). First alternator failed spectacularly. No question on that one. Second failed after 5 months - was a cheap unbranded replacement. Third one which is the current one displays the same behaviour as the vehicle in this video. Smart alternator. As low as 12.7 a idle, atnd tops at 14V under load. Indy garage that fitted this latest one wasn't convinced it was working correctly until I showed them this video. They learned something too...

[@winkerr2338]

I had a similar issue a couple of years ago, one of the guys at the shop changed out 2 alternators in 2 days and the car got towed back the day after fitting each unit after breaking down with a flat battery. I had to check it out after it got towed back the second time and it was charging fine, both loaded and unloaded, I couldn't find anything wrong with it. Then I got to thinking, it was the middle of winter at the time so there would be a big continuous load on the alternator, so I let the engine run for 15 mins with the heater fan and lights on, came back and battery voltage was 12.something volts. Turns out part of the cable from the alternator to battery positive was corroded so the voltage drop got worse the longer the alternator was under load. Since then, I always load the alternator for at least 10 mins after the initial check.

[@sh2697]

so if it broke down, may i ask what the problem was

[@winkerr2338]

@@sh2697 The battery was being drained because the alternator couldnt charge it. The alternator was outputting 14.5 volts but the battery was getting less than 11volts (I'm assuming less than 11v because the lowest I measured was 11.3ish) while the customer was driving through the night, they noticed the headlights were getting dim (again), they stopped and the car and it wouldn't start again because the battery was flat. There was so much resistance in the corroded cable, it partially melted the junction box

[@fredsalter1915]

Great advice, sir. Thanks!

[@tammilutz7955]

I’m pretty sure something like that is causing my alternator to not charge the battery. I’m dreading trying to find the problem. Alternator bench tested fine. 3 new batteries. Alternator isn’t charging the battery.

[@brucebratschi4300]

Might it have been wise to turn lights, heater fan, rear defroster, ecg and then checked to see that alternator puts out amps it is rated for?

[@dogman8436]

Thanks! Been servicing cars for many years and learned new information here.

[@OzMechanics]

If you feel like this video helped out, feel free to support the channel by donating. Just one click away on the link below, to help support the channel :) www.paypal.me/ozmechanics

[@chrishernandez2490]

Wow did not expect that! Learned something new today.

[@OzMechanics]

Yep, in automotive, it’s always some new and fun to find out

[@Mr18Chapin]

Something new I learned today. Thanks a lot man 👍👍

[@HankAttack89]

Thank you this was extremely helpful As a tech myself I never knew this

[@EdgarLopez-ik3yk]

Good job man. You just showed again scan tools are a great help . But we do have to know how the systems work in order to come up with the most accurate diag. That means we need access to information . Newer cars are loaded with high tech. We have to educate ourselves more than ever. God bless.

[@OzMechanics]

That is 10000% true.

[@spyder000069]

I had these same symptoms on my F150. Threw me for a loop and and at first I swapped the alternator as well which didn't fix it. The actual cause for me was a bad ground from the engine to battery. This was tripping the computer up and when you had lights and heater on it couldn't source enough amps through the bad ground to keep up. So I just added an extra ground cable right to the engine mount of the alternator and ran it to the negative on the battery and not only did it fix the voltage problem but now my starter is much faster as well. I'm in the rust belt of Illinois so I am sure the original engine to frame/battery ground is corroded or gone. This situation is easy to test if you just use a set of jumper cables and only use the negative leads and connect one to batter and the other to a solid connection on the engine.

[@fredsalter1915]

Clever! I like it!

[@user-nv9sd8zk6r]

Thanks for information

[@eloinamontemayor9067]

Ok ok let's try it.

[@PhillyDee215]

Honest mechanic👌

[@ianhenderson4441]

Yes Nice Diagnosis and research , i always like to see my Alternator Compensating Voltage whilst under load ,,,enjoyed The video well explained ...........

[@efman2k3]

Great video, Thanks for posting!

[@OzMechanics]

Thanks for watching

[@steveb.6267]

Good video, I actually learned something new today 😳

[@OzMechanics]

Thanks for watching

[@d.d4184]

Nice video. You see this on ford's a lot. The commutation wire going to the ecu brakes lite comes on and out put from altanator is 14 + voltage.

[@Lambros_Stefaneas]

Bravo. nice video. Thanks for sharing your knowledge.

[@OzMechanics]

Thank you for watching

[@johnhnetkovsky8917]

You should check voltage drop while the alternator is loaded-- carbon pile, accessories .etc.

[@robertmobileman8304]

smart charge ,good video cheers

[@mikechiodetti4482]

My 06 Nissan Frontier 4.0L V6 will start out at 14.0 volts then ramp down to 12.9. When lights, A/C, wipers, etc are added, it still maintains 12.9 to 13.0 but the current output increases until the loads are removed. It's normal for the system to do this. Good diagnosis Oz.

[@heartlandmechanic]

Nice job , Research pay's off .

[@billyyoder8171]

Thank you Oz. Good job. Have a blessed and safe week to you and your family.

[@mikecont9742]

Learned something new. Never seen that....

[@thomasandrews9355]

My Honda Accord Sport does this. So I knew immediately they got ripped off =). Subbing brother.

[@stevenkietzke5582]

Thanks Oz Happy Easter

[@luismarty1685]

Thank you Oz. You the man.

[@sulemanhabib6349]

I love your work,keep it on (Oz)Habib auto, from Ghana accra

[@aussie_xsf]

That was the one thing I needed to learn for the day 😀

[@OzMechanics]

Well glad you popped in to watch

[@aussie_xsf]

@@OzMechanics It was actually very interesting to learn that some vehicles charging systems behave that way, electrical problems give me the biggest headaches !

[@squidben5780]

Great video, I thought my alternator was not charging would stay around 12 had to restart the car 3 times before the voltage would go around 14! guess it saw batterie had gone down from me starting the car 3 times in a row before it considered turning up the demand on the alternator. Great and informative video!

[@wesleycooper2647]

The more challenging task: writing up the repair order in language the customer can comprehend

[@OzMechanics]

That was really hard. But I will show them this video so that can help out as well

[@autotec01]

Gotta love computer controlled alternators,,,,I also had my ass handed to me on a 2016/chev 1500 pick up !

[@Jpilgrim30]

I don’t see how shops are still missing things like this. Smart charging systems have been around for years now.

[@jgeorges3061]

OZ, AWESOME it is great and the right way first to do ur basic checks as u did and read the info to verify the way system work thanks for sharing brother.cheeeeers

[@temeteme2608]

that was a useful insight. Could you tell us about the current at the moment of cranking?

[@thetinpin]

My Ford has a 'generator voltage desired' pid. Is that equivalent to the duty cycle desired (obviously in a different format VDC vs DC%) in that hyundai or is that not a fair 1:1 comparison in one way or another?

[@1977jelliott]

Most of the computer controlled alternators these days have load dependant charging, emmisions and efficiency and all that are a big thing, no point in driving a load that isn't needed

[@sh2697]

so the car didnt charge. something was wrong. Can someone tell me what was replaced? I really like the snap on tool you have

[@1977jelliott]

@@sh2697 The alternator on the vehicle was working correctly, under conditions when there was minimal electrical consumption, the control system was turning the alternator off, some people don't know of this function on some modern vehicles and it can be mistaken as a faulty alternator.

[@chicanesimon]

What he said ^ I was curious to see your test method txt book checking , good vid

[@path4514]

Its called elc.engine load detector

[@gloveyourway2000]

@@1977jelliott Spot on! It's been available on cars for a few yeas. My first EFI car (manufactured in 2006) had a computer controlled alternator. If you want to learn more about your car, download and read the manufacture's repair manual (one the one used by the dealership mechancis to repair your car). It contains heaps of useful info on how your car works!

[@carlosmbonilla5797]

do you think 2007 toyota rav4 2.4 work the same, i ready replace 3 alternator aftermarket end o got the same like your video..

[@gabrielcabrera3567]

Great video i also learned something new n helpful OZ thank you

[@georgecurtis6463]

Yup, they aren't going to charge more if there is no need. Back in my day we had older testers that had carbon pile testers in them. One could turn up the resistance and if the alternator started to charge more then one knew that it was ok. What was fun is to increase the resistance to see how good they were to the point they went below 12v. If that eng was still running then you knew the alt was really good. If it went below 12v rather early then you knew you pretty much had had brushes. Good job in diagnosing that no problem issue !

[@mikekotarba5828]

Thank you for the video

[@mikethompson3534]

Yes my 2012 Honda Civic does exactly the same thing as soon as you start the car the alternator is charging the battery to 13.5 -14.7 and after a minute or 2 it drops the voltage back to about 12.3-12.6 I almost changed the alternator after replacing my dead battery which was the original problem and did a test by simply turning on the air conditioner and seeing the voltage jump to 14.5-14.7 and later letting the alternator charge the battery it went down back to 12.3 -12.6 volts and as long your battery light on your dash does not illuminate your good to go but thank you for proving that with you scanner as I don’t have one 😊

[@javiTests]

I don't know in the US but in Europe that is a feature that most new cars have. I've tested that in a european 2013 ford focus (so 8 years ago). Ford calls that systen "micro-hybrid" because it recovers energy when you aren't accelerating. For the whole system to work, it has a controller that measures current going in and out of the battery and knows the charge. If the battery doesn't need to be charge, the voltage would be around 12.5V or something like that, even lower when the start&stop system stops the engine because all the electronics are working but the alternator is stopped. In this way the car consumes less fuel. If you're driving around and lift the accelerator pedal, the system engages the alternator and it'll go to 14.4V or so because that is "free energy". In the case that the battery is too low, the system will charge the battery and you'll see 14.4V even at idle and the start&stop system won't work until the battery is charged to a certain level. You have to be careful when changing the battery though. You have to reset this controller (at least in the ford focus) in order for the system to recognise that it has a new battery. We had to change the battery once and I told the techinician to do it (they had a tool from EXIDE to do this) but he insisted it wasn't necessary. The result was that 2 months later the battery was dead. They replaced the battery in warranty and reseted the system and everything worked fine then.

[@DavidGutierrez-zi4dy]

EXCELLENT I live by Allen genoa/Spencer near your shop.

[@OzMechanics]

Awesome. Hey that’s for watching

[@faustogonzalez8397]

Great video Oz, this is the 1st alternator video I've ever seen on KZbin indicating ~ 12.4 Vdc at Idle. I believe most of the Alternator videos I've seen would have called this a Bad Alternator, do you know if a 2006 Toyota Tundra would operate like this Hyundai, i'm always monitoring the Alternator voltage and it seems Low ~ 12.6 to 12.4 at idle but when cruising and off idle voltage jumps up to 13.6 to 14.1. Thanks again for your video.

[@billrimmer5596]

Great vid!! Oz is in SnapOn and Autel heaven. Nice place to b. Lol

[@neilufe]

That obd looks expensive and very informative. So it charging at a higher rate is normal when under load I had replaced 2 alternators and changed brand on the third one to get constant 12v even under load my god your awesome

[@stealthg35infiniti94]

What is the rule of thumb for "Old School " non ECM/PCM cars? I believe that it should be ~13.6V at idle regardless of load.

[@grahambeech4636]

I am having an issue with load at the moment. Alternator failed and then replacement failed. Supplier was good and replaced it & tested it before sending and the auto elec also tested it. No issues. I am now finding lights dip and fans slow when I lift off power. The power dip is fluctuating at lower engine speeds. When driving at night if I lift off power the lights dip. Regulator on alternator is fine. It is a 1999 BH9 Subaru Outback 2.5. I was wondering what else could cause the issue. I can feel an issue developing with power steering pump (it has become jerky) which is on same belt. Could it cause an issue.

[@fabianolalde6719]

Years years ago on a 2003 expedition that's happen to me. Ended up with fusebox internal soldering was bad resoldering an boom fix it

[@alanclarke5979]

Field sensing alternators are suppppeerrr common on late model cars, good trick for beginners to check that first

[@OzMechanics]

Yea, I got my butt wiped on one when I was so focused it was like a regular alternator. And I didn’t help I didn’t have service information in my finger tips

[@alanclarke5979]

@@OzMechanics yeah, painful to deal with the first time if you aren't aware of them 😂😂, I had issues with one a long time ago and just assumed it was a faulty regulator 😂 swap it out....still faulty.....then I started hunting...... Always pays to research before throwing parts at it.....especially 3 alternators😂😂😂

[@willzgn]

That's how the manufacturers up the gas mileage by adjusting the field current with the pcm.

[@johnkeefe3467]

I noticed that exact same problem on my Subaru, when I was trying to jumper lead charge my solar Batteries, then I noticed the Charge increase when I switched on my Park Lights.

[@chrisclift7921]

My 83 Toyota 22r does this exact thing with an external voltage regulator?

[@Sebastianx115]

Didn't know they do that but also you can graph the connector on the alternator to see the duty cycle

[@mentor288]

Hi Thanks for the Great channel and Great videos. I would sugest you notify the name of the workshop in order to get More customers in touch with a honest mechanic like you. Further More it would be Great IF there was some More info on the overall cost of the repair including How manny hours of work is suited for each Job respectivly.. Anyways i did enjoy the videos and picked up a trick or two from you so thank you 👍 🇦🇱 🇺🇸.

[@OzMechanics]

I’ll make sure to use these. Thanks for watching

[@hsubdarb]

What was the customer complaint if the system is working properly? I would assume battery drain overnight.

[@abudi1416]

What about if the battery light flashing when the voltage drops to 12.9 in Hyundai Toscana 2020 engine 2.0

[@MrCoreyCoreyCorey]

Thank you for the video, I'm in the middle of this on an '04 Corolla. Can you remember if the customer's battery light was one? Mine is. I will check codes and repeat the drop tests. I replaced battery and alternator already. Thanks!

[@user-mo8gt3uv4o]

Great video

[@counterintelligencereports7867]

Alternator diodes keep going bad on Dodge Grand caravan 2012. Any ideas why???

[@richardmitchell7836]

Great video, just curious was the customer changing the Alternator based off of just the voltage readings? Or could there be a Parasitic draw?

[@OzMechanics]

I believe the first problem was an alternator. But after the new alternators were installed he would check the voltage and notice it would be 12 volts and he would take it back to get it replaced

[@richardmitchell7836]

@@OzMechanics well I guess we all have to learn the hard way. I got caught on my honda with this issue as well, change the Alternator and battery bc they were both bad and had the same readings and started testing based of of the readings, bench tested the Alternator and said hmmm...so I went and used my buddy subscription to pro demand and learned about smart charging. The vehicles are becoming to smart..IMO making them stupid lol. Thanks for what you do!

[@OzMechanics]

@@richardmitchell7836 yep, that’s how I learned about this. Honda

[@grabovg]

Great work man. It’s funny that we’ve had smart alternators for quite some time but people still don’t realize it. Superb explanation of the system and showing how it works. One question I have. Did the versus not have the PIDs for duty cycle?

[@OzMechanics]

That is right. The verus only showed desired, not the actual duty cycle

[@cjstubejackofalltrade1551]

I had the same problem. I cleaned the rust on the alternator and changed the rusty bolt and everything was sorted

[@fire7765]

Great job

[@44warden]

Thanks. Just subbed.

[@watajob]

A data driven tech... wow! Good stuff, although that seems a bit dicey to me if you use vehicle for short, low load trips.

[@senorgeese]

I just ran thru 2 alternators thinking they were broken on my 2012 civic because the battery died after running the AC and music for 5m idling. Because the headlights weren't on, it didn't trip up to 14V and that was apparently enough to drain it.

[@roberts1159]

Interesting troubleshooting and analysis of the data. What started all the replacement alternators in the first place ? Customer measuring the 12.3 V and then assuming that’s a problem?

[@OzMechanics]

The first time they replaced the battery, I’m sure it was probably because of a bad alternator. But the customer ended up telling me later on that he checked it out because his battery was drained, but told me that he believed he left the lights on. I verified That with a parasitic draw test and also the alternator test that was done on the video.

[@roberts1159]

@@OzMechanics Thanks for your follow up reply. I have a 2015 Accord and connecting my DMM a few times noticed similar voltage readings. Didn’t realize PCM controls alternator voltage with newer cars.

[@russellstephan6844]

Nice demonstration of an on-demand alternator. Makes sense, really. Why waste power unnecessarily?

[@path4514]

I thought everybody knew this!I found this out on a 15 Chevy malibu

[@toddstidham8374]

I also see the alternator has an over running clutch on the pulley. These allow the alternator to spin free at certain times and can also show low voltage under no load. I should add that by accelerating the engine, you should see the voltage increase and decel will let the alternator free wheel and lower voltage.

[@laurawashington7227]

Wud that battery light on discharge the battery at night time as it sits?

[@CryptoKevin]

I noticed you were from Texas. I live in League City. I just replaced my alternator on my 2013 Hyundai Elantra GT with a remanufactured one from Amazon. It worked perfectly for about an hour but failed catastrophically within about an hour. At this point I don't know if the new alternator failed or something else is causing it to fail. I'm going to have the new alternator checked today and go from there. If I can't figure it out I might come see you.

[@OzMechanics]

Morning Kevin I just recently recorded a video where the customer bought some amazon spark plugs and they ended being cheap aftermarket knock off that had the OEM name on them. Caused a lot of problems

[@Thumper43230]

What part of Texas are you in? Having an alternator issue right now.

[@tatialo37]

Cool video!!!

[@PaulCTownsend]

Love it good job

[@OzMechanics]

Glad you like the video. Thanks for stopping by Paul

[@lyndahg4149]

Had same issue on my truck come to find out the amps on the alternator that parts store gave me didn't match the amps for my truck as per Haynes manual putting more higher amp alternator won't make light of check charging system turn off putting the required correct amp alternator worked light turned off.

[@TheThreeLeggedChair]

I love you!, in a manly way... good video.

[@OzMechanics]

I also love you as well. In a manly way of course

[@miguelsantos9606]

I have question I have a 2005 corvette with a built engine my alternator when the voltage goes down to 12.2 the velts make a noise when it starts charging again no noise so I sent my alternator to California have them rebuilt it I put it back on the car and still does the same thing but still a round 12 please give me an idea 💡

[@miguelsantos9606]

The alternator brand is DC power engineering

[@savage_9641]

I have that in grand marquis 2001 ? How can i fix it ??😓

[@geno2001h]

I have a 2006 Honda odyssey on the negative side it shows 0.2 volts as soon as I disconnect the negative side the millimeter shows it’s 11.6 but when i use a jumper cable it shows the alternator charges 14.5.

[@cessealbeach]

Nice Troubleshooting there, Some folks don't understand System Description, lack of comprehension, They just shot-gun parts

[@jct300m]

Is this whats called a variable speed alternator??

[@master2all]

Why did the car owner bring it to your shop? What problem did they want you to fix?

[@sandyruiz4696]

this is the new ecm alternator charge control system. this why you see a variable charge.

[@OzMechanics]

Of course. I explain that in the video in full detail

[@lordstevewilson1331]

I had charging voltage problem on my sti, in the end it turned out that my ECU had a coding issue and it wasn't commanding the stupid smart charging alternator. ECU faulty alternator good. My mechanic reprogrammed the ecu so it's no longer a smart charging crap. So not it puts out 13.5 to 14.5 all the time. No more problems. 3 mechanics could not work our the issue untill current one.

[@mandop8326]

Damn bro, you saved me from changing my alternator from a 2nd time! I just got my alternator rebuilt and was about to take it back because I wasn’t getting a higher voltage than 12.5 until I did the battery load test and the voltage started going up like the video. I got a Honda accord 2016. What Honda were you referring too?

[@OzMechanics]

Awesome 😎 glad this video helped you out. I believe it was a Hyundai Electra if I’m not mistaken. Yea, these smart charge systems can take you on a loop. Thanks for watching

[@chasedowney9814]

My check charging system is on in my 2012 civic si. I replaced the alternator and it fixed it for 3 months and then came back on and now can't drive it . Keeps not charging my battery

[@ciscokid0307]

can a loose or faulty ground cable lessen the life of an alternator?

[@vinayakpawar9127]

Sir I didn't understand actually what's happening to this car I need to know what is the solution you found in this car please give reply I am waiting for your reply..... N I really want to say thank you for sharing your knowledge n I am learning a lot by watching your videos you are doing a great job thanks once again

[@OzMechanics]

There was actually no problem. The customer was thinking that because it read 12.5 volts it wasn’t charging but with this system it’s a smart charge. So it charges at 12.5 at no load but jumps when we add load to the engine

[@Blazer02LS]

Both alldata and prodemand have this in the operational section. Guess the other shops never bothered to look, or more likely, couldn't see past the $$$ The Alternator management system controls the charging voltage set point in order to improve fuel economy, manage alternator load under various operating conditions, keep the battery charged, and protect the battery from over-charging. ECM controls generating voltage by duty cycle (charging control, discharging control, normal control) based on the battery conditions and vehicle operating conditions.

[@jimmyg5636]

I have a 2018 Durango and I had electrical issues. First the main battery went dead no start no crank. Apparently the auto stop/start battery was already dead. The dealership couldn’t find the problem. Second visit they found the stop/start battery was officially diagnosed dead. 230$ later the system worked. Then the main battery went dead again. Diagnosed as a dead cell and was replaced 460$. Now the alternator under acceleration load will drop to 12.8. No load coasting 14.5 same at idle. Chrysler said this is normal logic from the ECM. To me it seems counter intuitive