Tesla Low Voltage Charging System

[@marcioporto3584]

Hello, I'm from Brazil and an electrical engineering student focusing on electric vehicles since 2020/2. Your explanations and teachings are really cool.

[@patsplat]

Good to see you back!

[@WeberAuto]

Thank you so much. I have been gone too long teaching my EV classes.

[@ruly999]

this is one of the best tear down channels on the internet, glad to see more of Weber Auto's high quality content

[@WeberAuto]

Thank you very much!

[@carloshernandez8512]

I'm so happy to see you back, Professor Kelly. Thank God you're in a great, healthy shape.

[@humidbeing]

One of the best auto instructors on youtube! Glad you're back!

[@WeberAuto]

Appreciate that

[@bhiatt53]

Welcome back! Your vids converted a 71yo never-EVer! I absolutley love my new Model Y! More, baby, more!! 👍👍

[@WeberAuto]

Right on! That is awesome

[@BobQuigley]

72 yr old convert here.

[@MrPatdeeee]

We, are happy, that you are back John D. Kelly. For there is NO one; that can do it like You. Thanks Sir, for we❤you! Amen!

[@WeberAuto]

Thank you so much!

[@MrPatdeeee]

@@WeberAuto ❤

[@avaya272]

Professor, I'm so glad that you're back!

[@WeberAuto]

More to come, thank you!

[@g.l.g.6064]

Great to see you back, 80yr old that enjoys the knowledge that you teach future mechanics. 😎

[@WeberAuto]

More to come!

[@jmwarden1]

Same here from 81yr old

[@andersd6817]

I wish I could have your voice in the in-car navigation system, guiding me to my destinations 💫

[@WeberAuto]

LOL, thanks!

[@EngineMisfire]

@@WeberAuto I read you can create your own voice prompts for Waze. Worth investigating.

[@xzivr4894]

So glad you're back! This channel has been extremely helpful with my own EV conversion. From understanding the design intent of various systems to safety guidelines to mechanical teardowns and explanations. It's GREATLY appreciated!

[@WeberAuto]

Thank you so much!

[@filippozampicinini6546]

Welcome back Professor Kelly, we have missed your lectures a lot. Greetings from Italy

[@WeberAuto]

Thank you! 😃

[@phillyphil1513]

good to see you Professor Kelly, woke up to go to the bathroom, get a snack and now i'm literally watching this at Zero Two Thirty Dark (2 : 30 a) here on the East Coast. 😁

[@WeberAuto]

LOL, thank you very much!

[@renuing]

So happy to have to filming again, the information you share and depth you go into is gold! Thank you

[@WeberAuto]

Thank you so much!

[@berndschneider1708]

Glad you’re back, Sir. A retired workshop manager here, working for many years on hybrid and hydrogen vehicles. I learned a lot from your videos, which are very informative and well done . Please continue. Kind regards from Italy

[@WeberAuto]

Thank you very much

[@lone_wolf_XIII]

We missed you dearly, so satisfying listening to the husky voice. Oh, also all the informative information too! ❤

[@WeberAuto]

😊 thank you

[@adarlurei]

was rewatching your Rav4 Hybrid from 3 years back and boom new EV video just pops on! Nice to have you back. 🤗

[@WeberAuto]

Thank you very much

[@Digital-Dan]

So happy to have such an elegantly designed system.

[@WeberAuto]

It really is!

[@Tylerspyler]

This is a great video. Everything you have discussed seems very accurate and well researched. The only thing I will say is, When dealing with the HV battery connections, If the points being touched have known high voltage, or are unknown/untested, it is recommended to only have one hand in that area. The other behind your back/ at your side. All it would take is a pinhole in your hv gloves to allow voltage to get you. If you have both hands in, the path of electricity is through your heart. While it is a worst case scenario, it is possible. Also, if the HV battery is being serviced, it is suggested to remove the pyro disconnect to halve the voltage. Everything else I saw here is well done.

[@WeberAuto]

Thank you very much. Great comments on safety procedures.

[@louspinelli1745]

So glad to see you back, I have been suffering terrible withdrawal symptoms during your absence. You are irreplaceable. 🎉

[@WeberAuto]

Thank you so much!

[@vevenaneathna]

missed you bro. have been running my gen1 chevy volt off of a 32 ah lifepo4 battery i built which saves ~50lbs of weight. also have a solar roof which keeps the low voltage side topped off through an mppt. teslas bump in voltage and the videos on youtube are what gave me the courage to try this. beeing running fine for the last year with no bms, just an inductive active balancer and a thermostat relay board/heating pad. your videos on the gen1 volt is partially why i got the car. best car ever imo

[@Nicholas-f5]

Great for short trips before the gas engine turns on perhaps

[@vevenaneathna]

@@Nicholas-f5 good for my 185 mile commute so i only end up using 2 gallons of gas lol. charge at home, charge at work.

[@WeberAuto]

That is awesome. The first gen volt was an amazing car.

[@stargazer7644]

You're running a lifepo4 battery with no BMS? Why in the world would you do that?

[@vevenaneathna]

@@stargazer7644 more max amp discharge rate, no low temp lock out, cuts the price by around 50%, better balance capability with active balance boards, less self discharge, no low state of charge lock out. and its probably safer given that most lithium fires are started by bms that drop a cell or malfunction. all of these make a lot of sense in an automotive application, its why lead acid batteries dont have bms' lol.

[@erack1]

Yes!!!! I was looking forward to what was next for the model 3. Watched all your videos. Has gotten me to a point where I'm seriously thinking about signing up for the courses at Weber State. Thank you, Mr. Kelly for your time and knowledge!

[@WeberAuto]

Glad I could help!

[@liveandletlive2894]

I'm thinking about it too. Just wondering how much previous electrical or in general mechanical knowledge is necessary as I'm pretty new to this.

[@itburnswhenip1963]

Welcome back Professor Kelly. Glad you’re going to be putting videos up again.

[@WeberAuto]

More to come!

[@rahatsalwan2251]

Thank you for coming back

[@WeberAuto]

My pleasure

[@tonybennett638]

So great to see you back Prof ..

[@WeberAuto]

Thank you!

[@boscogong4242]

You guys always post great videos. You always explain things well. You're a Great Instructor.

[@WeberAuto]

Thank you! 👍

[@Doctorbasss]

Good to see you back! The CATL LI-Ion small battery seem to be kept at about 80% SOC in average.. Which suggest that 80% could be probably be a great charging setpoint for NMC cells just like the LG from the big battery are.

[@WeberAuto]

Thank you. That the percentage I use on my Model Y

[@liveandletlive2894]

It's not the greatest comparison because the Lvb is lithium ion

[@emmexfyv]

Wonderful to see new stuff from you, you've been missed!

[@WeberAuto]

Thank you

[@fama6472]

Professor Kelly, thank you for your video. The simplicity with which you describe complex things denotes your profound wisdom and skill in teaching. Kind regards from Italy.

[@WeberAuto]

Thank you very much!

[@johannesdolch]

Enjoying these videos very much. Thank you.

[@WeberAuto]

Thank you!

[@AbrahamLeanin]

For the love of everything, yes please continue this series!!!! i will gobble up anything tesla related.

[@karlosk5773]

Thank you so much for covering this topic! I've been eager to learn about the Tesla LV System for quite a while.

[@WeberAuto]

Thank you!

[@Henry_Jones]

Glad to see you back!

[@WeberAuto]

Thank you!

[@carlosfranchi5043]

I'm glad you' re back sir

[@WeberAuto]

Thank you kindly

[@edwardnack]

Wish you the best from 🇷🇴 Romania

[@WeberAuto]

Thank you

[@user-td9sm5fu3f]

Scrivo nella mia lingua, tanto c'è il traduttore. Professore è un grande piacere ascoltarla.🔝🔝🔝 Saluti dall'Italia 👋

[@WeberAuto]

Grazie mille

[@GammaCruxis]

Welcome back! You look great 👍. Glad to see you hale and hearty. Cheers!

[@WeberAuto]

Thank you very much

[@user-cu2xi6mz7y]

Man i am so glad you're back, i am electronics engineer i love your videos, hope you're in good health, welcome back!!

[@WeberAuto]

Thank you very much

[@djosbun]

Great to see you back, Professor!

[@WeberAuto]

Hey, thanks!

[@Maltanx]

So nice to know a new series of video is coming! Thank you Professor!

[@WeberAuto]

My pleasure!

[@benjaminrich9396]

Good to have you back John. :)

[@WeberAuto]

Thank you very much

[@alsn126]

thank you for your videos. I graduated as a auto technician and I miss the workshop settings. these videos really help me stay tuned and updated. thank you

[@WeberAuto]

Great to hear!

[@htnowpro]

Great to see you back❤❤. Don't forget the Honda clarity battery 😢...Happy to see you producing again.

[@WeberAuto]

Thank you, I will

[@GOVAUS1]

Thank you. It's been great to watch. Glad you are back.

[@WeberAuto]

Thank you very much

[@hip-flowtv]

So great to see you back teaching on KZbin! You’ve been missed, and I’m sure so many of us are excited to learn from you again. Your explanations have always been clear and inspiring, and it’s amazing to have you sharing your knowledge once more. Thank you for coming back and continuing to inspire us!🫶🌷

[@WeberAuto]

Thank you so much!

[@siberx4]

As a Bolt owner, your series on the car's electrical and battery system was hugely instructional to me and was fascinating to watch. Those videos made me a fan of your unique clear and compelling presentation style though and led me to watch your other videos, and I'm excited you're back and creating videos regardless of the subject because I've found your other lectures just as engaging. Good to see you again!

[@WeberAuto]

Glad you enjoyed it. Thank you!

[@까꿍-t6h]

So happy to see you again

[@WeberAuto]

Thank you

[@alibehboudi]

i am so happy to see u again DR kelly ,please dont forget us

[@WeberAuto]

I have not forgotten. I just had too many other obligations for my time.

[@alibehboudi]

@WeberAuto I wish you all the best dear master

[@mikechiodetti4482]

GREAT to see you professor! I know maybe 1% about a Tesla, so I'm learning from you. Thank you for this info and a great starting point. Without the low voltage starting point, the H.V. Contactors cannot engage, that is if they're like other EV's.

[@WeberAuto]

Thank you. You are correct

[@Not.nickelodean]

WE HAVE MISSED YOU!!! Glad to see your informative videos again!

[@WeberAuto]

Thank you so much

[@abdullahalgburi960]

I watch your videos from Iraq, I enjoy listening to the information that you give, Thank you, I wish you continue

[@WeberAuto]

Thank you

[@zeelax]

Professor Kelly, glad to see you back!

[@WeberAuto]

Thank you!

[@stevebollinger3463]

Great to see you making videos again. I know there are others who cover the systems of electric cars but yours are consistently the best and most informative. An invaluable resource. I see you've yet again raised the production quality on these videos. Not that it was needed but it is very impressive. Look forward to more videos. How did you get those perfect captures of what is on the Tesla center console screen? Does it have some sort of video out port you can use? If you just pointed a camera at the screen then you did an impossibly good job at it!

[@WeberAuto]

Thanks Steve. There is a screen capture function in the Tesla Toolbox 3 software. I made a video about it here: kzbin.info/www/bejne/oarRm4xsl5hkpcksi=B5xEWXdgess0eRgS

[@pak0070]

Thank you sir for come back

[@WeberAuto]

Thank you

[@khuo0219]

I love these videos you speak so clearly! Feels good to know how my car works

[@WeberAuto]

Great to hear!

[@johnrbnsn]

Glad you’re back!!

[@WeberAuto]

Thank you

[@hybridsolutiondiagnostics]

Nice to see you back Professor 👨‍🏫 always the very best 👨‍🔧👨‍🔧✅✅

[@WeberAuto]

Many thanks!

[@briq4409]

Awesome having you back. I checked the channel a bunch of times. Thought maybe somehow I turned off notices. Thanks for doing this again. Your videos are great to watch.

[@WeberAuto]

I appreciate that!

[@richardmiller4388]

Excellent comprehensive summary of the LV system and available diagnostics. Extremely useful to the eternally curious. Please keep it up!

[@nyc6035a]

Great video and explanation. Glad to see you back making great content.

[@WeberAuto]

Much appreciated!

[@jonnycando]

Welcome back! I plan to visit Mexican Hat and other places in Utah come May!

[@WeberAuto]

Thank you! There are so many cool places to visit.

[@phillyphil1513]

@@WeberAuto if you're into Military Aviation check out the collection at Hill AFB. also buy a ticket for the Museum of the Natural History (aka Jurassic Park). both of these places are HIGHLY recommended.

[@mribi]

Thanks, you are a one of a kind EV teacher

[@WeberAuto]

Thank you very much!

[@jasonneugebauer5310]

Great video! I am so happy to see you putting out more of your excellent car system education videos. Your videos are amongst the very best I have found anywhere.

[@WeberAuto]

Thank you very much!

[@MarioDallaRiva]

Great to see you, professore! 👏🏼

[@WeberAuto]

Thank you! 😃

[@farche2]

Could listen to this sort of content all day.

[@im4udevco]

It’s been a while Dr Kelly and so good to see you back. I’ve been watching all your videos seeing Tesla making history ushering a new era in battery electric vehicles along with other new entrants. The Japanese and some of the ones still burying their heads in the sand have not been evolving and slowly becoming irrelevant right in front of our eyes. It’s fascinating seeing history in the making when it comes to electric vehicles and battery technology and I hope to live another decade to see how things change.

[@eightbitwhit]

So glad to have you back Professor Kelly! I love your videos and appreciate all the work you put into your content. Keep ‘em coming and we’ll be here to watch and support!

[@WeberAuto]

I will. Thank you!

[@TTemobility]

I love those Videos which bring a lot of Content. Thank you from Doc Tesla in Germany

[@WeberAuto]

Thank you so much

[@HYBRIDEVMASTERSGARAGE]

Professor been thinking about you - Happy Holidays. 🙃

[@WeberAuto]

Thank you very much. Same to you.

[@GoatieDK]

Extremely theral walkthrough.... perfect !

[@WeberAuto]

Thank you!

[@scottvannederynen6429]

Happy to hear you are going to begin shooting videos again.

[@WeberAuto]

Thank you!

[@dennisthemennis99]

This channel never lets me down with the quality content! Thank you for making great videos

[@ouch1011]

YES! Hearing that THE Professor John D. Kelly will be recording automotive technical videos again has been the best news I've heard all day. I no longer work in the automotive industry (techs don't get paid well or treated well enough) and moved onto the manufacturing industry, but still like to learn and stay up to date on automotive technology. Your videos are a reminder of what I really enjoyed about the automotive world, shame that the service/repair industry had to ruin it for me. A small bit of personal experience with the 16V Li-Ion batteries in newer Teslas: my partner was recently in a major collision where he was hit by a drunk driver who was going well in excess of 100mph on the freeway. My partner was in our (late) 2022 Model 3, drunk was in a mid 2010s Mustang. The Mustang hit the Model 3 at least 40mph faster than my partner was going, rear ending him and hitting with basically a 20% overlap in the right rear. It wiped out the Model 3 basically all the way up to the right rear door, where the Mustang seemed to then get pushed off, avoiding crushing the passenger compartment (kudos to Tesla for making the passenger compartment secure). Where I _wasn't_ impressed was in the low voltage battery reserve capacity. As a result of the impact, the Model 3 got launched into the center divider of the freeway (cable barrier) which shredded the left side of the car and basically ripped the charge port off the car. I don't know if this caused a short or if Tesla does this in all collisions, but it blew the pyrofuse and shut down the low voltage charging system. The 16V battery (which was only a couple years old) was dead within 10 minutes, causing all the windows, doors, trunk, frunk, glovebox, etc to ALL be disabled. Most importantly, all the vehicle lights went out. This crash occurred at 2am while my spouse was driving to work. That meant that a car with zero functioning lights was sitting in the middle of the freeway. Thankfully the police had already arrived by that time, but that is not always the case and could have led to a catastrophic secondary collision. It also made the vehicle incredibly difficult to get into after the fact when trying to recover property from the car before it got scrapped.

[@WeberAuto]

Thank you and thanks for sharing. I am sorry to hear about the accident. hopefully he was able to get out of the car before the battery shut off.. The 16V battery has a lower reserve capacity. In my tests here on campus, they typically last up to 20 minutes (depending what was turned on) before shutting the car off after the low-voltage charging system is turned off.

[@360compass]

Excellent detailed description! Glad you are back on KZbin.

[@WeberAuto]

Thank you very much!

[@yarrum3]

good to see you back from Australia

[@WeberAuto]

Thank you very much!

[@СергейНеизвестный-м3я]

Thanks for the new video! Glad to see you again!

[@WeberAuto]

More to come!

[@RealBLAlley]

Another excellent explanation of these systems.

[@WeberAuto]

Thank you!

[@jackbartonwarman]

The Tesla charging technology,wich was unknown to me ,was explained to me clearly and perfectly .Great!

[@WeberAuto]

Thank you!

[@petermolnar6017]

Welcome back Professor Kelly! We have been missing you...

[@WeberAuto]

Thank you very much

[@emceh]

Finally new video - thank you for such important topic :)

[@WeberAuto]

More to come!

[@emceh]

@@WeberAuto I hope so - we missed your detailed explanations :)

[@Stefan_Dahn]

The legend Professor Kelly is back! Love your superb videos! Best regards from Germany! 🇩🇪❤️🇺🇲🤝💪

[@WeberAuto]

Thank you very much!

[@rodzenasr1]

Welcome back professor. Learning is a joy!!

[@WeberAuto]

Thank you! It is!

[@WinstonsGarage]

Love these videos. Can you make a video on removing the PCS? PCS failure is very common on 2018 Model 3s and this would be very helpful!

[@WeberAuto]

Yes, I am working on a video where the entire battery is disassembled, including the PCS.

[@liveandletlive2894]

​@@WeberAutoyay!!

[@MikesTropicalTech]

Great to see you back here Professor! Looking forward to the next series of videos.

[@WeberAuto]

Thank you kindly!

[@tommckinney1489]

Welcome back! Great video as always!

[@WeberAuto]

Thank you

[@ghall05]

I love that Tesla labels all of the parts in their cars! lol JK Cant wait for more of your videos! Your knowledge of these cars is unmatched!

[@WeberAuto]

Glad you like them!

[@TechScottBrown]

And when you get to the board level there’s even more verbosity. This level of detail is hard to find on other vehicle manufacturers

[@joedwc]

Welcome back!

[@WeberAuto]

Thank you!

[@jeffh9071]

Watching your videos makes me feel like I snuck into an official Tesla training session for their techs 😁

[@WeberAuto]

That is awesome. Thanks

[@thespiceislife2082]

Glad to see you’re back. My experience with Tesla’s low voltage monitoring/warning system wasn’t good. The 12v battery died without warning one morning. I opened the back door, put my bag in and closed the door. I noticed that the window didn’t roll back up and I couldn’t open any other door. Chatted with Tesla on the app and they didn’t see any alerts, but said it sounded like the 12v battery had died. They towed my MY to service and after 5 hours they replaced the 12v battery under warranty. The 12v battery error only showed up after temp power was connected. My coworker had her 12v battery die while charging without error messages. Mobile service was dispatched in her case. Maybe the low voltage battery needs a larger reserve to provide more time for failure detection?

[@WeberAuto]

Thank you! Their 12 Volt batteries have had shorter lifespans (3-4 years). The 16 Volt systems have better battery state of health monitoring.

[@tomgnyc]

We missed you!

[@WeberAuto]

Thank you!

[@mikaeljohnson]

Greetings from denmark. I love watching your tesla content. Best wishes from a happy m3 highland owner 😊

[@WeberAuto]

Thank you! 👍

[@deang5622]

Same mistake a lot of KZbinrs make when showing electronics. No schematic/circuit diagrams. Circuit diagrams are a really useful way to explain what is going on.

[@Nicholas-f5]

Would be great to get Big Clive to deep dive

[@WeberAuto]

Thanks for the feedback!

[@Derpy1969]

Welcome back! You’ve been missed.

[@WeberAuto]

Thank you!

[@MarsPlastix]

Alléluia good to see you back !

[@WeberAuto]

Thank you

[@Stefan_Dahn]

Danke!

[@WeberAuto]

Thank you Stephan! Much appreciated

[@Stefan_Dahn]

@@WeberAuto Your tutorials are priceless, but I try to give a bit back. Well deserved! 💪👍

[@ronolsberg1468]

Great to see you back with a new video! You mentioned a wire that is used to maintain the LV battery charge level while the vehicle is sleeping and it does not require the HV battery contactors to be closed to do so. When I monitor the voltage level on our 2023 Model 3 LV battery using a multimeter or Bluetooth voltage monitor, the voltage level drops slowly over a six day period then wakes (the contactors close) to replenish the charge level. Did I misunderstand what you described in this video regarding this?

[@WeberAuto]

Thank for the feedback. Good catch! Tesla made a firmware update to reduce the electrical loads when the car is off. They got rid of the "Standby Power Supply" system and introduced a "Sleep Bypass" system. "When the Model 3 goes to "sleep" the new sleep bypass will turn on and connect the entire low voltage system directly to the HV Battery to supply a continuous 10.6V rather than relying on just the LV Battery for power." "During Sleep, there is some LV current draw through the Sleep bypass. This average current is reported after the vehicle wakes up by VCFRONT_sleepCurrent. While 500 mA is the minimum threshold for the Sleep state, it is high enough to drain the LV Battery to the point where it requires support relatively quickly. Ideal vehicles have an average sleep current of about 75 mA, while the majority of vehicles draw around 120-130 mA. There are many factors that affect LV current draw, the largest issues being 3rd party devices tapping into the Sleep Standby Supply." This information explains what you are seeing. Thanks again. With as often as Tesla issues firmware updates, I need to check my service information for changes before publishing a video like this.

[@ronolsberg1468]

@@WeberAuto Thanks for the response! Searching for "Sleep Bypass" it appears there might be a low power Buck DC-to-DC converter located in the Penthouse or possibly the VC-Front controller that directly gets its power from the HV battery and does not require the HV Contactors to be closed. In the event of an accident, a blown Pyrofuse would presumably isolate this direct bypass connection to the HV battery?

[@WeberAuto]

Yes, an open pyro-disconnect would remove voltage from the connection to the HV battery.

[@Hill-qf5yr]

Welcome back! You are always the best! Waiting for you for a long time.

[@WeberAuto]

Thank you!

[@AndyM...]

Thanks Professor, am also glad you're back, one thing that struck me were the AC cables going into the PCS, they seem to be quite small cables for reasonably high current, long duration charge events. Also did the Telsa' s support 3 phase charging, if so thought there might have been extra cables. I have a Kia EV6 which has been fantastic, I'd imagine some principles would be similar. As always thoroughly entertaining and educational, look forward to more future videos. 🤠😎

[@geezerider1]

Thank you! The low voltage system now makes sense.

[@WeberAuto]

You're welcome!

[@BlueSpruce2]

Very clear explanation of the system Professor Kelly. Several times during this video I was asking myself why do they need a separate battery for the low voltage system when they can convert the main battery voltage to whatever they need? Afterall, they are still bypassing the contactors to maintain the LV battery when the vehicle is switched off and they can monitor the main battery SOC to prevent it going completely dead. At the end I think you indirectly mentioned it. In an accident, the main battery is disconnected from the vehicle however they may still essentially need emergency LV power for other life safety systems. The other reason of course is the contactors themselves need an independent LV power source for actuation.

[@Nicholas-f5]

It's required by federal law FMVSS

[@BlueSpruce2]

@Nicholas-f5 I'll take your word for it as I can see the safety implications especially on modern vehicles with their power windows and door locks...

[@WeberAuto]

Thank you very much!