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Discussion Starter #1
I was doing some reading regarding the Model S 90D and there seemed to be quite a lot of reports of faster than expected battery degradation for the 90D. However, all those reports seemed to subside, so did the issue go away? Was it a case of fast degradation for the initial % of the battery but then it settled down? I'm looking into getting a 3 year old used Model S and debating whether to get a late 85D or an early 90D. The 85 pack seemed to have a solid reputation for battery degradation.

Also, was there any significant battery changes between the pre-facelift 90D vs the facelift 90D?

Thanks in advance
 

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There are 3 different 90 battery packs and it was the earlier ones that suffered most. Its the onl y battery I'm aware of where they went through versions and I believe that was to fix the problem, and as a happy coincidence they also release more power each time if you had a P car wiith ludicrous. The later the production the later the battery as a general rule although with cars potentially having battery swaps under warranty there could be odd balls out there.

The problem was largely an early and steep degradation that cost I think about 10% (5% being the norm for early degradation) but even then few dropped below the 85, which of course now has its own problems. They also clipped supercharger speeds. The degradation hasn't appeared to get worse on those 9 batteries after the initial drop from what I've seen - and a car has either suffered or it won't (famous last words as I'm a 90 owner)

You can see the battery version if you're looking to buy - I can't recall exactly how other than kneeling down and I think there's a serial number plate on it somewhere - worth googling if you're looking to buy, especially if you're buying a P90DL as the later battery has the extra performance.

If its just for the degeneration, you can look to see what degneration the battery has had following this fairly simple guide


I wrote it and I believe it to work fine - as a point of reference, my car has about 94% of the new capacity and its a 3 years old MS P90DL with 35k miles on it and still superchargers as high as 127kw. But mines also a V3 battery. If you're looking at a 90D not a P90D, you could just try the calculation especially if its a prefacelift car and see what comes up. I can't be sure, not sure anybody really knows, but if the degeneration if reasonable (under 10%) then I believe it will supercharge at 100kw+.

Sadly can't guarantee any of this as each car is different and Tesla could bring a software update out tomorrow that changes things - but its as I believe the situation.
 

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The 85 battery has 77.5 kWh useable, the 90 has 81.8kwh useable in theory, the 90 having about 4kwh more. While the 90 battery was losing more than expected in some case, it rarely lost 4kwh more than expected so the capacity did not go below a similarly used 85 battery. You’d almost always have more capacity in a 90 than an 85, what annoyed many 90 owners was how much they paid for what was meant to be an extra 5 kWh (85-90 is 5) and ended up only 1 or 2 kWh.

The 85 issue is relatively new. The long story short is there have been battery fires and the earlier generation batteries, the 85 being the most common, have in some cases been heavily restricted through software to protect them. This has in some cases removed and extra 10% of their capacity over and above normal degradation. It’s been called batterygate and owners literally had 10% taken via a software update overnight. Tesla are denying it’s a warranty issue.
 

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Discussion Starter #5
In all honesty, it'll either be an early pre-facelift 90D. Or an early facelift 90D (if the extra cost is palatable). Thanks for the info, good to know that the degradation issue stabilised.
 

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Thank you Jon.

The 85 battery has 77.5 kWh useable, the 90 has 81.8kwh useable in theory, the 90 having about 4kwh more. While the 90 battery was losing more than expected in some case, it rarely lost 4kwh more than expected so the capacity did not go below a similarly used 85 battery. You’d almost always have more capacity in a 90 than an 85, what annoyed many 90 owners was how much they paid for what was meant to be an extra 5 kWh (85-90 is 5) and ended up only 1 or 2 kWh.

The 85 issue is relatively new. The long story short is there have been battery fires and the earlier generation batteries, the 85 being the most common, have in some cases been heavily restricted through software to protect them. This has in some cases removed and extra 10% of their capacity over and above normal degradation. It’s been called batterygate and owners literally had 10% taken via a software update overnight. Tesla are denying it’s a warranty issue.
 

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I run a 2015 Model S 90D and mine was one of the first shipped so I think has the A release battery. Pretty much from new 100% equated to 75kWh which was a bit dissapointing, although in theory (not mine and not tested in practise!) there's about an extra 5kWh buffer at 0%. My car is now at 111k miles and has been supercharged a lot and is now capped at 97kW max charging speed. 100% now seems to work out at 72.5 to 73 kW, and is on the latest software available (2019.36.2.1) for my car. The only battery issue I've had is the 12V lead acid which a Tesla Ranger replaced FOC on my driveway even though out of the main warranty. So far my car has been very reliable with only one unscheduled trip back to the service centre (a steering UV joint that went tight) and is on track to beat my most reliable car ever (a gen 2 Prius) and better than my last car (a gen 3 Plug-In Prius)!
 
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