Battery Life

Are you using rechargeable batteries with your scale? I contacted the customer service as I'm also experiencing the same problem. Since I'm using rechargeable batteries, they informed me that this kind of batteries will not last as long as non-rechargeable batteries in the scale. But if you're using non-rechargeable batteries, you may contact them using this link https://support.withings.com/hc/en-us/requests/new.

My WS-50 is killing new batteries within 3-5 days as well, i need immediate help what to do.

Good luck ... Customer service was very little help to me. Didn't offer a solution, just offered a discount on new unit. I threw my $170 unit in the dump and moved on to a different brand. 

Mine suddenly started doing the same after being great for a couple years. Suddenly, less than a week and fresh duracells are dead. 
Maybe a bad firnware update? No response from Withings

They never answered the question. The battery drain is caused by a bad firmware update, but they won't fix it. There are several other threads about this same issue, but Withings just marks it 'answered' and tells users to buy a new scale. See if they tell you the same.

I performed a factory reset ( https://www.manualslib.com/manual/1203499/Withings-Ws-50.html#page=55 ) and it solved the battery drain issue. I had to try several times pressing the two buttons in the back to finally get “factory” to show in the screen.