Blancpain

Just picked up a used Fifty Fathoms and am loving it. However, I am a little concerned about the lume. If I charge it for about 20 seconds it is almost dead in ten minutes. I would have expected much longer. I just sold a Sub C and I didn't purposely char... 

After a 20 second charge: 5 minutes later:...  

And this for whatever watch brand. Just never seems to hold up. Best regards, George