If your battery is deeply discharged, it can be difficult to recover it. However, there are a few things you can do to try and resuscitate your battery.
First, if the battery is completely dead, you'll need to charge it for an extended period of time - 12 hours or more. Once it's been charged, try discharging it completely again and then recharging. This process may need to be repeated a few times before the battery will start holding a charge again.
If your battery is only partially discharged, you can try charging it for a shorter period of time - around 6 hours should suffice. Once it's been charged, try discharging and recharging again as needed until the battery holds a charge once more.
It's important to note that batteries that have been deeply discharged are more likely to fail in the future. So if your battery doesn't seem to be responding to these resuscitation efforts, it may be time to invest in a new one.