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Water damaged battery repair at EcoAuto in Tewksbury, MA

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RDoc

2021 Prerefresh Model S
Aug 24, 2012
2,835
1,805
Boston North Shore
This is an edited repost of a message I posted last month that appears to have disappeared into the aether.

In our 2015 Model S 85D we recently had the battery damaged by driving through about 2" of water. It splashed up and got into the battery through the corroded cover over the pyro fuse. After going through the water we got a warning that the car might not restart, so we drove home and parked the car and, sure enough, it wouldn't restart.

The fuse cover corroding and letting in water is a very common battery killer issue with early Model S cars from sometime before 2016 so owners should have the battery dropped and the cover checked!

Fortunately, our comprehensive insurance covered it so we had the car transported to EcoAuto in Tewksbury, MA where they diagnosed the problem and offered to repair rather than replace the battery which the insurance company agreed to. After they tested all the modules it turned out two were bad which they were able to order and replace along with the pyro fuse, the cover and some miscellaneous other stuff. There were no remanufactured batteries available from Tesla, so the only other option was a new battery for around $20K.

The cars now works fine and seems to have recovered at least part of the range it had previously lost from normal degradation over 95K miles. When new, the car had around 250-260 miles of range at highway speed, ~70 mph in 50-70F weather. Before the battery work it had gone down to around 220+ miles. After the replacement it's now back to about 250 miles range. I've measure this a couple of times with over 100 miles of driving each time so, while totally unexpected, I think it's real.

This took awhile, over 5 weeks total, but the cost was quite reasonable IMHO. $6303.65 total, $3362 parts and $2700 labor. The battery modules are $1500 each so the cost depends a lot on how many modules are bad. My understanding is that there are 16 modules in the battery. They were able to diagnose this with equipment they have in house so everyone knew what we were getting into before the repair started.

I have no interest at all in EcoAuto except as a customer. I'm just posting this because it seems like an option other Tesla drivers might like to have. Incidentally, they were very pleasant to work with.
 
I'm no expert by any stretch of the imagination. However I have been doing a lot of reading. And one thing I red about module replacement is that the entire battery will get too much out of 'balance' after a few months of charging/discharging. So I'm curious to find out if this battery is still OK in a few months - a year?
 
Thanks for sharing, I am also in same boat just removed the HV pack P85D pyro fuse cover completely corroded and water puddle inside,
 

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I'm no expert by any stretch of the imagination. However I have been doing a lot of reading. And one thing I red about module replacement is that the entire battery will get too much out of 'balance' after a few months of charging/discharging. So I'm curious to find out if this battery is still OK in a few months - a year?
They did an explicit battery rebalancing operation that took about a day at the end of the repair.
I believe the battery management system is constantly rebalancing the battery since, even without any replacements, the cells aren't all the same so they're going to age and behave differently.