In winter in Novosibirsk the temperature dropped to -25, and I noticed that the driving range fell by almost 40% compared to summer. Is this normal or is the battery starting to degrade?
Totally normal! Cold is just brutal for batteries, and that goes for literally all electric vehicles, not just Tesla. When it's minus 25, the chemical processes inside the battery slow down, its resistance increases, and efficiency drops by 30-40%, so you're spot on. Plus in winter you've got the cabin heater running, which uses a ton of energy - that takes another chunk out of your range. This isn't degradation, it's just physics. Once the battery warms up while you're driving, things will get a bit better, but you won't get back to full summer capacity until it actually gets warmer out.
As for the long-term health of the battery, frequent extreme cold does affect it, but slower than constant heat or complete discharge. If your Model 3 is parked somewhere unheated for a whole night at minus 25, the battery will be super cold before you start, and then energy consumption will just go through the roof. My advice: if you can, park in a garage or at least under a carport, and pre-heat the battery through the app before you drive if that's an option. And don't stress about degradation - this battery was specifically designed to work in harsh conditions! With Tesla it's normal to keep the capacity without major losses for many years, even in Novosibirsk.
Preheating the battery before a trip is what actually helps, and a 40% drop in range at -25 is more of a temporary efficiency loss due to cold rather than degradation. Though I should clarify - are you measuring the range right after the car's been sitting outside overnight, or do you let it warm up in the garage first?
A 40% drop in such cold is actually within normal range, but not the worst that can happen. Cold slows down the chemical processes in the battery, making it less efficient until it warms up. Usually at minus 25, people lose anywhere from 30 to 50% of their range depending on driving style and whether there was preheating. Over time this recovers completely - it's a temporary thing, not degradation.
Here's what's important and often overlooked: watch how the battery behaves when the car is parked in the cold for a few hours. If you go outside and see that the range dropped right while it was parked (without driving), that could be a sign of problems with insulation or battery management. It's normal when losses only happen while driving because of increased internal resistance. But if the battery is draining while sitting still - that's a reason to get it checked at the dealer.
As for long-term degradation: in Novosibirsk, where winters are harsh, it's better to park your car in a garage or heated space if you have the option. Constant extreme cold does wear the battery faster than a moderate climate. But one winter at minus 25 won't ruin the battery - that's normal wear for an EV in harsh climate.
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