Late to the party but I figured I'd share my battery stories with you all just in case others might have had similar experiences.
I have a 2013 P85 Model S . Last October (and less than 2 weeks out of warranty) with 75k miles on the car, I got the "Maximum Battery charge reduced" warning on the display. I got home and plugged it in (with 130miles left on the battery) and to my dismay, it wouldn't take a charge.
I took it into one of the California Bay Area service centers and was told "Your battery is dead and you need another".
The quotes for replacement were:
New battery =$25,508.00 (written quote)
Refurbished Battery = $9-13,000. (verbal quote)
I begged for mercy since I was just 2 weeks out of warranty and added that the car had spent more than 2 weeks in the shop for miscellaneous repairs and a big repair where the drive unit had to be replaced. I asked for some kind of Goodwill and after weeks of back and forth with them, I was told they would give me $4k off a refurbished battery. Taking that into account, I did the math and now I was looking at a quote of 9-13k MINUS the of $4k discount which would land me at = 5-9k Right?
Well, when they gave me the new quote, it was now $17k total - $4k =$13k . Which was not a discount at all from the previous refurb Quote.
At this point, my car was at 130 miles, wouldn't take any kind of charge and was slowly counting down to being a brick.
I parked it at home and a few weeks later after trying to work with the service center, the battery had dropped down to 59 miles. Another software update came in so I updated it then in effort to keep the battery for continuing to lose charge, I plugged it into my 120w outlet at home to see if I could keep it from being completely dead.
To my surprise, it went "Click" and green and started charging! I was able to charge up past the 130 miles I had when the problem started, so I got in the car to move over to my 240 outlet and I saw that the warning message was cleared from the dash and I was able to charge to 90% ( I didn't try for more) on the 240w outlet.
When I went back to the dealer, shortly after, for the eMMC chip replacement, they asked if I was going to replace the battery now. I told them I didn't need to because it was working fine now and the message went away.
I' happy to say my car and battery were fine for the past year with, no issues whatsoever....until this week.
I saw the "software update" message on the dash a few weeks ago but I was skeptical about installing it since that was when things seemed to have gone south last time.
Eventually I got tired of clearing the message from my display, gave in and allowed the update (last week). A few days later, I Supercharged to a 90% Trip level, then at 170 miles I got this "Maximum Battery charge reduced" message.
It changed the Daily and Trip settings to where the daily starts at about halfway instead of at 80%
Once I got down to the halfway point I tried to charge again but it says charging complete.
I'm back at the point where I was a year ago and this seems suspect to me. I believe this is a software/firmware issue.
Has anyone else ever experienced problems like this soon after doing the software updates?
I plan to go into the local service center and see what kind of treatment I get this time.
I'll keep you posted if you are interested.