I received the dreaded "12 volt battery needs to replaced soon" warning on my 2015 MS 85D. Here's what I did.

• I watched several videos of people changing their own, and decided it didn't look too hard.
• I found a couple of sources for new batteries - the best was Gruber in AZ. Cost $138.
• I put in a service request to Tesla. The response was quick, but the service appointment wasn't - it was not for a few weeks.
• I contacted Electric Garage in Ocala and left a VM.

Here's what happened next:

• I got a text message from Tesla saying they could do a roadside tech swap in a few days. The price is $217.50 with labor and 1 year warranty (I was expecting over $300).
• Then 1/2 an hour later another text from Tesla saying they could be at my home the same day!

I weighed the cost of ordering a new battery and figured I'd have to add at least $20 for shipping, then having to wait several days to do the job myself, against the cost of getting it done immediately without getting my hands dirty.

It was a no brainer, especially considering the car could die at any time. So it's done.

The Tesla technician was great (I've had him do work before). A few things he told me:

• The old battery was original. This contradicts what a lot of people have complained about, saying they don't last long. The car is 5 years old and has 76,000 miles on it!
• After you get a warning message there is no way to know how long it will take until it just dies, potentially leaving you stranded!
• Tesla has recognized this issue and now prioritize battery replacement calls, which is why they came so quickly.
• Doing it yourself is easy, BUT they have to do a software configuration to the car afterwards. Obviously this step would be missed, with or without consequences.

So I'm very happy with the outcome. The average life of a battery in any car is apparently about 4 years, so not an unexpected maintenance issue.

I have not had a response yet from Electrified Garage, but to be fair, they're still in the process of opening their shop, and it's now only 4 hours since I left the message!