Install Nintendo 3DS battery in the Wii U gamepad?

Sa
- in Nintendo
1

My Wii U gamepad battery is unfortunately pretty exhausted and hardly lasts. Since I don't have a spare battery, but still an old 3DS, I wanted to ask whether it is possible to safely use the 3DS's battery in the Wii U gamepad. Unfortunately, I have no idea.

Bl

Will be difficult, just because the batteries have a different size…