I Have This Speaker Dock For My Ipod But I Know It Will Drain The Battery Life What Should I Do?

i really like listening to it outloud and have it on whenever i’m in my bedroom, but when i put it in it constantly charges which is REALLY bad for my ipod battery.
i’ve had my ipod for over a year and i’m afraid if i keep using it like this it wont last much longer, and i just got these speakers which were $50 and i cant afford a new ipod rite now.
how do i play it and keep it from charging?
how bad is it for my ipod, will it not matter that much?
its called an iMode
“docking station for iPod”
in the corner it says iP215.