Sealed 12v Battery belongs to the category of rechargeable batteries, if they are ignored, not charged after use, not charged properly, or have reached their expected lifespan, they are complete.

　　If it dies completely, it is gone, and you need to find a replacement. If you are lucky and still have enough juice, you can connect it to a smart battery charger and get more life from the battery while desulfurizing the lead plate and bringing it back to its original place.

　　Complete five charges/use cycles to see if this can effectively remove sulfur to restore battery performance. To do this, please charge the battery fully, use the battery until it is exhausted, and then repeat this cycle five times.

　　Hope you are lucky, if the battery is not badly damaged, you can make full use of it.

　　The downside is that after the initial use, the longer it has not been in operation or the longer its service life, the less charge it retains (if any). When the Sealed 12v Battery is a new battery, its capacity should be 100%, which means it can maintain the expected fully charged state.

　　A battery that has not been charged for a long time or is close to its expected service life after use will have poor performance and will lose its ability to be fully charged. Instead of maintaining 100% capacity, it will gradually drop to 90%, 70%, 40%, etc., until it dies.

　　The best way to extend battery life is to pay attention to it, especially in winter. It cannot be left idle for a long time and is expected to be executed when needed.

　　Sealed Solar Battery is also our product, welcome to consult and purchase.