diff --git a/app/src/rgb_underglow.c b/app/src/rgb_underglow.c
index db3ea490f98..661ff71672c 100644
--- a/app/src/rgb_underglow.c
+++ b/app/src/rgb_underglow.c
@@ -177,7 +177,7 @@ static void zmk_rgb_underglow_effect_swirl(void) {
     state.animation_step = state.animation_step % HUE_MAX;
 }
 
-static void zmk_rgb_underglow_effect_battery() {
+static void zmk_rgb_underglow_effect_battery(void) {
     struct zmk_led_hsb hsb = state.color;
 
     // Only set lights if battery information available, otherwise set to blue