Problem with accelerometers failing on multiple Wiimotes

Hi there! We have a custom video game that uses Nintendo Wiimotes paired to a Dolphin bar. The game runs on a PC. It is a racing game where the speed of your horse is controlled by quickly moving the Wiimote up and down. We have had significant problems with the accelerometers failing. I made sure to only purchase genuine wiimotes and over a 2 week public campaign we had at least 10 controllers stop working. Any ideas on why this might be happening and any tips on how we can prevent it happening and/or fix the Wiimotes that no longer work? Note: The controllers stay paired and the D pad still works, just not the accelerometer. Thanks in advance!!

Josh.