battery is constantly discharging quickly

What is "quickly" and what is the iPod doing during that time.

Is your battery worn out? How long have you had it? Since the battery is lithium-ion, over time using the battery and charging and discharging over time wears out the battery. If you've had it for a few years, this might be the case. If it is fairly new, it might be just a bad battery. If so, you might need it replaced. The warranty should cover it. If this still does'nt help, describe a little more about the device. Depending on factors of the device the reason could be a lot of things. Hope this can give you pointers. Hope it helps! 🙂