Vivoactive 3 battery drain s/w 6.60 problem

Update on my watch , after the sw 6.6 it didn’t last more than 12hrs the watch was 18 months old so I complained via email to Uk garmin they have since changed the watch with no charge so I am very pleased with the outcome so if you are in the same boat I suggest emailing 

Had my watch since July this year, generally its only used as a watch, it doesn't have any other watch faces other than standard or any other widgets or apps.  
I have  used it a few times recently as a HRM connected to my 520.

Charge had been lasting 5 to 7 days I would say and not been as issue at all.

The watch updated to 6.90 last week at some point.

I fully charged it Thursday night before going away, it was all but dead Saturday afternoon.
Older watches may have dying batteries but not one that's a few months old.

my VA3 battery now lasts just 12hours, ive been 6 months or so with the battery problem and garmin didnt give any explanation or at least i couldnt find one, i called tech support in argentina, where i bought it,  and  they said that probably it is a board problem and will take 15 days to repair it, not for free  because 1 year warranty is over ....

I contacted customer support.  They first tried to have me delete some files which didn't work.  After that, they sent me a replacement/exchange. I'm sure my watch was an older unit- I recall upgrading from the original Vivoactive not too long after the Hr unit was released.   The replacement watch has been working fine- averaging about 4 days/charge which I'm happy with.  I can only assume that there is a compatibility issue between newest firmware and some older hardware.  You need to submit your serial number with the request to customer support, so that probably gives them a starting point for diagnosing the problem.

Yes, I also sent back my watch for warranty and Garmin replaced a new one too. Although that takes some times, but at least it get fixed, together with old scratches removed..  hahaaa

• I had a fully charged watch when I arrived at the start of the New York City Marathon. 45 minutes before the gun it was at zero. I had to run my race without it. This is the second Vivoactive 3 Garmin has replaced.  I’m losing confidence in it which is a bummer because I love the watch.