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2021 M3LR Battery Replaced Recently (Experience)

Sure-Ad-7283 | 2026-03-07 19:19 | 7 views

Got the dreadful **BMS\_a079** warning on my 2021 Model 3 Long Range at 108k miles. I charge to 80% on the daily and charge to 90% for longer commutes once a week. During lunch, I got the Unable to charge - Maximum charge level reached (BMS\_a079). If you get this error, schedule the service appointment right away. Although my appointment was 10 days out, I ended up taking the car in the next business day. It will tell you you can continue to drive and charge up to 50% but that is not true. I drove it the next day and got it to about 44% and tried to charge at home. It would not charge. Then I started getting the **BMS\_a074** (Maximum battery charge level reduced) error every minute. Once I took the car into the service center, they already had the HV battery on order since I had booked the service appointment 3 days prior. They pretty much know if they see that BMS\_a079, it will require a HV replacement. Service advisor say they keep some battery packs on hand but also have local warehouse that stocks them. I dropped my car off Monday morning. The HV battery replacement completed Wednesday afternoon. I did have to request a loaner. Be persistent if they say they do not have any on hand and it depends on eligibility. If the repair is under warranty and it is an extended/long repair, service center should provide you a loaner. I looked at the repair invoice and it was indeed the REMAN battery (1137375-GC-W). Based on research on the reddit and tesla forums, they try to match an equivalent degradation battery. In my case it seemed pretty close. At 80% before the battery failure I was at 231 miles range and now with the REMAN battery I'm at 234 miles at 80% charge. I still haven't charged to 100% yet on the REMAN but previously on the OG battery I was around 291 miles at 100%. Since it was replaced under warranty, the REMAN battery is only covered until the remaining of the original 8yr/120k battery warranty. I'm wondering if I should get the 24month/30k battery warranty extension for $2000 as I approach the 120k. I read posts that the REMAN batteries do not last as long as OG batteries. Trying to see what others have experienced when it comes to longevity on the REMAN batteries.

Comments (8)
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RealDriver3604 2026-03-07 20:13

Not surprised to see another one. Bummer. Mine just did the same a month ago with 62k miles. Seemed to be more time than miles. Personally I'd go with x-care if I were to get something or plan to use recell if the failure occurs out of warranty. Debating if it's worth keeping/worth the risk (which seems high) out of warranty.

PapaEchoLincoln 2026-03-08 01:17

Do you live in a climate with lots of rain/humidity? There are some rumors the 2021 HV battery failures are due to moisture infiltration

spewing-oil 2026-03-08 03:08

Is the reman a 2021 battery? Anyway to figure that out?

sablerock7 2026-03-08 14:29

There are tools you can use to monitor for cell imbalances, but I would be cautious about keeping a reman pack out of warranty or paying $1k / yr for the privilege.

Empty_Wallaby5481 2026-03-08 15:02

What tools would you recommend to monitor for cell imbalances?

These-Delay6072 2026-03-09 12:38

Either you setup a fleet api yourself or use dr.EV or similar app.

Master-Journalist888 2026-03-09 16:54

I love that non-premium Teslas now come with 100k miles battery warranty as a cost cutting measure vs 120k miles. For people who can barely afford Tesla and pinching pennies Mr. Elon decided to make their life even better.

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