I use my iPhone linked to my Garmin Edge 510. It broadcasts my live route whilst out, but doesn't draw too much from the battery.
You can set it up to auto upload to Garmin Connect and there is also a plugin that then syncs to Strava. I don't use the sync with Strava though, as doesn't carry over the barometric bit and then Strava auto updates the elevation.
My current method is to just plug in to the iMac when I get home and upload separately to both Garmin and Strava. Works perfectly and unaffected by each other. Also charges back up whilst I ponder the segments of the day.
