If such situation happened, please check welding helmet by following procedure step by step:

1.Press "TEST" button located on filter lens

2.Filter change from a clear state to a dark state immedicately after pressing "TEST" button, and then changes back to be a clear state. That means battery is working. Pls adjust " SENSITVITY" knob to high.

3.Low battery light flashing for a second or filter doesn't change to dark status after presssing " TEST" botton, it may low battery. Pls change the battery immediately.