I replaced the batteries in both my HRM-Pro (1023425 -- the yellow one) and my Cadence sensor (814778) earlier this week and both batteries died within a day or two.
I got one workout out of the HRM immediately after changing the battery.
I did not get any workouts with the Cadence sensor before the battery ran down.
The battery in my Swim HRM (28687 -- the blue one) was dead, but I haven't used it in several years so that is not a surprise.
All connect fine to my Forerunner 935 when they have battery power.
Are the sensors trying to stay connected to the watch for too long? Is there something I need to do to tell the sensors to disconnect so they don't drain so quickly? When I'm done with the workouts the HRM gets hung on a drying rack in my bathroom and the bike is hung on a hook in my garage, so motion in both cases is limited and they should not stay connected for more than a few minutes after completion of the workout.
The wrist-based HRM works fine for cycling & running. Unfortunately it does not work well for weightlifting, which is when I (try to) use the HRM strap.
Am I stuck removing the battery after every use? Or replacing one or both sensors?