From "Friedrich Steiner" on Youtube, this is a mix of the Girls Und Panzer instrumental and the vocals from The Battle of Bulge, Lyrics from the original description:

Ob’s stürmt oder schneit,
Ob die Sonne uns lacht,
Der Tag glühend heiß
Oder eiskalt die Nacht,
Verstaubt sind die Gesichter,
Doch froh ist unser Sinn,
Ja unser Sinn.
Es braust unser Panzer
Im Sturmwind dahin. 2x

Whether it storms or snows,
Whether the sun smiles upon us,
[Whether in] The day's scorching heat,
Or the ice-cold of the night,
Dusty are the faces,
But joyous is our mind,
Yes, our mind.
Our tanks roar there,
There in the stormwinds. 2x

[Singable English]

In blizzard or storm,
Or in sun warm and bright,
The day hot as hell
Or bone-chilling be the night,
Our faces may with dust be laid,
But spirits never fade,
No, never fade;
Relentless, our tank
Thunders out on a raid