When charging a car and something isn't working as it should, it's difficult to immediately determine whether the problem lies with the charger or the car. With Tesla, the issue may be with the vehicle itself, not the charging station. How can you tell if this is really the case, or if the problem lies with the wallbox or the charger? The only way to determine this is to compare the failed charge with a subsequent charge at a different station. If charging works, then it's easy to assume the cause lies with the original charger used. But if the car doesn't charge, then it's easy to believe the problem is with the vehicle. It should also be noted that a single test won't be enough; multiple attempts will be necessary. Just because a charge works doesn't mean there's no problem. Therefore, it's helpful to be able to run multiple tests before determining whether the charging issue is with the charger or the Tesla.