If I email a developer about the 5.10 battery issue - will they be able to know what it is?

Yes, they would probably appreciate it if you identified an issue. They do rely on user feedback... doesn't hurt to try. 

Yes, I did email, will see what he says. I am curious what jim_m_58 might say, I know he is on this forum and I see his apps and faces on the IQ store.

With a battery issue on any device, the first thing to try is to reboot the watch - sometimes called a hard reset, but you don't lose any thing.  On the va4, press the upper button until the watch turns itself off (20 seconds or so), then plug it in and charge to 100%.  Sometimes the battery level is just wrong and this can help.  When ever I get a FW update, I typically do a reboot after the update is installed.

If that doesn't help, contact garmin support: https://support.garmin.com/en-US/

This is generally a user-to-user forum, so it's best to contact garmin directly.

Thanks Jim. Agreed that Garmin does not appear to be monitoring here. Hard reset has not helped. There is definitely something that happened with 5.1 that has caused this issue.

Forgot to also mention that when I contacted support their response was an offer to replace the device. Based on the experiences of many on this forum that would not help. This is a software issue, not hardware.

There is absolutely a V 5.0 to V5.1 difference in battery consumption with watch faces, and possibly with other IQ app too. The watch faces I've used so far are updated frequently, and the developers are active at updating compatibility and fixing bugs. The battery hit for me was negligible but still there...

I detest Garmin standard watch faces on the VA4, which make the watch feel much cheaper than it could be.

However, I'm now experiencing a near 50% drop in battery consumption with a Garmin watch face. I'm at 41% after 7 days and 3hours after pulling from charge. Disabled notifications, but BT connection to phone enabled. About 1.5h of GPS activity so far, and daily GPS barometric altimeter calibration. 

Change the watch face to something like Rails or Racing (no seconds) and this usage plumes to 4-5 days with battery down to around 10%. With V5.0 and earlier, I could get another day out of similar usage.

I would actually be OK with the standard analog face - if I could make the fonts bigger. I can't see the data fields without my reading glasses

for me the chunky aliasing drives me nuts on the analogue watch faces. There are many watch faces with anti aliased graphics that look fantastic comparatively 

I still wonder if there is anything the watch face developers can do to identify what is causing the issue. (And fix it.)