Trying to understand. Are you saying you have a solar piece of equipment that won’t take a charge in sun light or otherwise?  I’m no expert on this but I know battteries, at best, have a limited lifecycle. Even those rechargeable solar ones. If it won’t take a charge then either your solar component (I dont know what they can that specifically, or your batter has lived past its expiration  date. Other than installing a new batter or the proper solar sensor, I dont think there’s much that can be done except for you to replace the entire things. My point is, there’s probably nothing you can do to “fix” this.