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The place I heard about the guide is actually this forum. If you search for “Theory of Operations” you will see it occasionally mentioned on here….but I can’t seem to locate a copy.

I did not ever find the document I was looking for, or anything regarding balancing theory from any official Tesla documentation, unfortunately.

Good questions.....I drew that curve in excel, and exaggerated the flatness in an attempt to make the point clear. If you look up actual lithium ion battery curves, you'll see they're not quite as flat as I drew it. So the BMS can still make a good guess at SOC in the mid-range, but the...

Correct - you got it!

Yeah that would work just fine. Another nuanced detail that I thought was cool (again, from the smart reverse-engineer guys on this forum), is the bleed resistor control method is not closed-loop on brick voltage (I would have assumed the bleed resistors stay on until a particular brick voltage...

You are absolutely correct. The video posted in this thread is mine and I would like to provide some additional detail below: First off - I posted a slightly different version of this video onto this form a few months back, but it was quickly pointed out that I made several mistakes in...

Hey guys, I've been hearing about a document called "Model 3 Theory of Operations Guide" that I would like to read. I recently subscribed to Tesla Service, but can't seem to find this document for download. Is it part of the "Model 3 Service Manual?" I'm particularly interested in the...

Hey Zoomit - FYI I pulled the video down from Youtube due to the inaccuracy you brought to my attention yesterday. Thank you for getting @wk057 involved in the discussion. You guys really helped me out.

Thanks for the help mike!

Wow thanks for the detailed response! Clearly you know your stuff! I truly appreciate the education.

I just spoke with a colleague of mine with a lot of experience designing battery management systems. He said the “bleed resistors” referenced in that previous post are likely also used by the BMS as “shunt resistors” which can be switched across the highest voltage bricks during charging...

Well said. I bet you’re right - applying current to individual bricks would require a ton of hardware (isolated supplies for each brick for example). Using bleed resistors to drop bricks with the highest voltages back down into alignment would require considerably less hardware. Thanks for...

Thanks for sharing. I didn’t mean to add to the confusion….I was trying to help sort it out. We used the article below as one of the sources for the video: https://tesla-info.com/guide/tesla-bms-calibration.php Below is a snip from the article from April 2023: Cell balancing While the...

Hey guys, We've seen a lot of confusion regarding battery balancing vs. recalibration. There are several cases recently where ultra-conservative daily charge limits (50-60%) caused pack imbalance on relatively new cars with Nickel cells, and 90% daily charge limits and pack balancing every 3-4...

I'm pretty sure the power is cut to the center console USB ports when the car goes to sleep.

Thanks for conducting the detailed testing. Your results perfectly match my findings. I suppose the only thing yet to be tested is the Tesla OEM USB module in the center console. It will probably yield identical results, but I guess its possible the OEM hub will act differently than the...

Cool - thanks for the followup. When you try your USB-C stick in the center console for Sentry, keep an eye on the little alarm bell icon on your screen. If I recall correctly, the UI_a111 "error" does NOT pop up on the main screen. You'll need to click on the alarm bell icon to see the...

Thanks for the update - glad to hear your car is working normally. Did you try the Stoughton station that originally gave you trouble?

D Did you need to install the Tparts USB-C module in your console? Or did your car already have USB-C ports with data in the center console from the factory?

That is an interesting hypothesis. I am curious to see what someone else's screen shows in Service Mode when supercharging is complete and the charge handle is still plugged into the charge port. I wonder if other people's show 0V?

I realize this post is a year old....but I just noticed this exact same thing on my 2022 M3LR on the driver side rear (same as yours). Did you get it replaced? Or just leave it alone?

Thanks for the reply! It is reassuring, although unfortunate, that I'm not the only person having this issue. Lately I only get the error at the Seabrook NH supercharger (V2). I don't seem to get it anywhere else. Below shows an Invoice image from my latest service visit for this issue...

I used a mechanics pick tool....Basically a screwdriver handle with a "L" shaped hook at the bottom. Down at the bottom of the panel there are two slots that you can get a pry tool under. Once the hook was inside one of the slots, I yanked pretty hard and the panel popped off. I think another...

Yes, my data cable was behind the USB-C panel in the console. All I had to do was install the Tparts module and plug in the cable and it worked. I took delivery March 2022. Evidently around June/July they stopped including the cable. It is also my understanding the cable that was taped to...

Congrats on the install! I also have a FTM400 in my 2022 M3. I mounted my rig in the center console. The head is mounted in a tray on top, and the base is hidden underneath. The speaker on the base unit is only OK - a little hard to hear clearly when driving on the highway. I also found...

Thanks for the advice. Perhaps the cheap USB-C to USB-A adapter was causing the problem. I will try a native USB-C thumbdrive and see if that works any better.

Yeah, I felt a little silly asking the question. The error message is pretty cut-and-dry Re-Insert "USB into Glovebox for Higher Speed" I suppose I was curious if anyone had a workaround. I appreciate the answer!

Hey guys, Quick question regarding the thumbstick for Sentry Mode. I have a 2022 M3 and recently added data functionality to the USB-C ports in the center console. I tried moving the Tesla Sentry thumbstick to the center console using a USB-C to USB-A adapter and get an error: UI_a111...

My charging problem is not yet solved, but I have some additional information to share from "service mode." Below is a picture showing the alert descriptions. As expected, I have a few BMS_a063 alerts. I also saw the "VCFRONT_a530" alert, which was unexpected - I have no idea what this means...

For anyone curious - I put together a quick video showing the error pop up at the end of a Supercharging session (see below): I have not yet captured video of the error happening at the start of a Supercharging session.

I also had trouble finding anything on this same issue. I did find one post on a Tesla subreddit where a guy had the exact same problem, but he never resolved it. I also found a post on the UK/Ireland TMC where a bunch of folks had a similar issue that was resolved by replacing the “3 Phase...

Thank you for the warm welcome - it’s always fun signing up to a new forum! - My second service center visit regarding this issue is scheduled for next week. - I was able to “Report Bug” today when the issue popped up. - I’m going to drive to a few different supercharger locations this...

Not yet - but this is on my list of things to try. I'm going to try another V2 supercharger location - hopefully this weekend. I have backed into a supercharger that another customer successfully used minutes before myself - but I have NOT tried a second location all together.

Thanks for the reply. The first time I took the car in for service, they connected their supercharger and it worked normally, so they sent me home suggesting it must be faulty Superchargers. I am still having the problem. I even waited for a customer to successfully charge and drive...

You got half of the story correct. It happens both ways: - sometimes the car will charge normally and the error happens at the end of the charging session - sometimes the error happens a few seconds after I insert the charge handle and it prevents me from charging Obviously the second scenario...

Thanks for the "report bug" tip. So far Tesla service has pinged my car twice to look for "errors" remotely. Both were done a few hours after I experienced the Supercharging problem, and Tesla said "we don't see any active alerts." It looks like the BMS_a063 alert only remains active...

Hello everybody - first time posting (hopefully I'm using the correct form) I drive a 2022 M3LR in the USA with 7k miles. For the first 10 months of ownership the car worked perfectly. 4 weeks ago after heavy rain/snow/salt, I started getting CP_a051 which indicates a fault in the Charge...