The smart locks are intelligently created to withstand low battery for multiple days. However, it will put up a warning about the low battery throughout those days. One can charge it up in the meantime but under extreme circumstances, the battery might completely go off. When such a scenario arises, the digital lock products key, or simply the mechanical will be operable. It will easily open up the door providing access. The battery won’t be an issue for smart locks as they always have a fail-safe process and in this case, it is the mechanical key. However, it varies from product to product.