Good Gag for birthdays

Of the 15 balloons have managed only 2 pieces to shine more than a few hours. The 2 balloons lit even after 48 hours, which would have been the originally intended performance?!? The remaining batteries were obviously too weak.

Unfortunately, the LEDs flash in the balloons, I had imagined it differently, so that the balloons are lit steadily and a quiet mood lighting created. Instead, I had a flashing Christmas chain in large, for a short time ...

The children present had fun. I personally, however, the effect was too cheap. Not for a high-end event.

Would I then not buy unless the product is improved.