Does the car warranty extend to cover the replacement battery just as if it was the original battery? Given an EV battery is a pretty significant part of the cost of the entire vehicle I wouldn’t trust a swapped battery unless the manufacturer made it very clear that they would treat it as if it was the original battery if any issues arose with it. The last thing I would want is to have to fight with Tesla or whoever if the replacement battery fails and they claim it’s not covered by their warranty.