What Happens When You Put a Garmin Fenix 7 in 4-Degree Water for Several Days?
Originally posted on Twitter, July 1-July 5
July 1, 7PM
We don’t know when Nicola Bulley had last charged her Fitbit Versa 4. But let’s assume it was near 100% on Jan 27…
This is an apples-to-oranges experiment, but using a watch that claims to perform better than the Versa 4 probably only helps to make the point I and many others have been getting at:
An hour ago, I submerged a Garmin Fenix 7S at 96% battery life in cold water in a fridge that I had set to 4 degrees C. The Fenix 7S has a rating of 10 ATM (can withstand water to depth of 100m—the Versa 4 rating is 5 ATM / 50m). But depth is not really part of this experiment, just water and water temperature.
The Fenix 7S battery life is listed as 11 days with normal everyday use (i.e. not mega-long workouts every day). My watch is nine or ten months old and it’s 11 days unless I record a lot of workouts, then it’s more like 5-7. Also, it has a lithium ion battery which, as I said in my first post, generally performs better than Versa 4’s lithium polymer in extreme temps.
So we’d expect the Fenix to do…pretty well? Compared to the Versa 4 which is priced lower/not a direct competitor to the Fenix model. But in ONE HOUR, the Fenix has already lost 3% of its battery life, going from 96% to 93%.
Will update again tomorrow with progress and time stamped pics. If anyone can do this with a Fitbit Versa 4, please do.
July 2, 9AM
An update on my (admittedly flawed) experiment and some more observations.
Again, I'm using a Garmin Fenix 7S with an 11-day battery life and a Li-ion battery (which, along with the Fenix's different HR setting options, is largely what accounts for the longer battery life). So we can't make definitive conclusions about the Fitbit Versa 4. But...
• In 13 hours in 4C water, the Fenix 7 battery went from 96% to 91%. But after that first hour (3% drop), it only lost another 2% overnight. The main reason, I suspect: It's not tracking, or "trying" to track HR. The watch knows there's no wrist there. The LED lights switch off after seconds, as Garmin explains here:
And "--" appeared in the HR section of my watch face.
• This bit is important: Unlike Garmin, Fitbit heart rate capability seems to only have an on/off function. In other words, if you don't manually turn HR tracking off in your settings, it will continue to try to track even if the device is on a counter, table, in a bag, etc. Below is the HR graph of a Fitbit Charge user whose device was in his gym bag all day:
This problem has been observed by users across Fitbit devices including the Versa models. Fitbit *claims* that HR has some sort of auto setting, and that infrared light technology on the devices helps detect whether or not the device is on your wrist, but users with newer Fitbit devices have continued to complain about HR spikes being picked up off-wrist into 2023.
• So again, how do Nikki's HR spikes on Jan 27 through to Feb 4 prove she and her device were in the water? They can't—especially in light of the Versa 4's official battery life of "6+ days" (which does not account for 3C water). This is very sad to think about, but if there was data showing her HR smoothly and consistently (with no breaks) going down to zero, this should have been shared at the inquest. Otherwise, any spikes, especially if there were also any breaks in HR data being recorded, could have easily come from a device that was not on her wrist. Without more info, we can only continue to speculate on this possibility.
(Another thing that happened: The Fenix disconnected from my phone, despite being in range with bluetooth set to on on both devices. This is most definitely a bluetooth connectivity issue related to water submersion, which Nick Bennett on Twitter brought up a few days ago. As Nick observed, this would likely make it impossible to try to find her and her Fitbit with her phone during the search...that is, providing she and the Fitbit were actually in the water.)
July 2, 10AM
Another update: ~14 hours in, 90%. My Garmin's screen has frozen in between two screens and the buttons are longer working 😵💫
(Also condensation). Nicola I am willing to break my watch 4 U.
July 2, 11:30AM
Some reviews of Versa 4 that mention battery life, taken from all reviews, not just the negative ones. Based on these, her always-on screen setting must have been off, at least. Would have reduced battery life to maybe 3-4 days if on.
July 3, 7PM
Screen just came back on and it's actually at 68%, approaching the 2-day mark.
• So it's losing around 14% per day, but lost more rapidly in first few hours.
• I'd guess it will last 7-8 days in the water vs the standard 11 days for this model, whether it would still work at the end is another matter.
• If Nicola's Fitbit made it in the water, could make an obscenely optimistic guess based on the above that it might last 4 days, despite its different (IMO inferior) battery type. But my watch is not tracking HR, which is saving its battery life. Inquest police witness purported that her Fitbit was, in order to get those random HR spikes until Feb 4 🤨
• On that note, I spoke to Fitbit customer service this morning and they were adamant that none of their devices record HR in water. The LED lights "detect" water and "switch off," they said (my Garmin does this). But a Versa 3 user on Reddit reported getting their swim HR data *after* a swim activity, only in the app (pic 2). I've escalated the matter (😅) and hope to hear more tomorrow.
July 4, 5PM
Got some answers back from Fitbit. In short, false heart rate data recording in water IS possible with the Fitbit Versa 4.
Still have unanswered questions for them about:
• 8 days of battery life in cold water
• 9 days' worth of data retrieved off device when she was found
• False heart rate data known to record off-wrist
• False heart rate data known to record on-wrist in deceased wearers (who were not in water)
July 5, 8AM
Here's a chart of what's happening with the Garmin battery in 4C water and what I'd predict might happen with the Fitbit Versa 4.
In the chart, I'm giving the Fitbit Versa 4 a generous battery life of 8 days (Fitbit claims 6+ officially) in normal conditions. So let's pretend it lasts 8 days even though most reviews claim it's more like 5-6. If it lost battery life at the same rate as my Garmin has in the 4C water, I predict it would last max 6 days in water—*WITH HR TRACKING OFF.*
Next experiment will be to see how quickly the Garmin battery deteriorates while on my wrist in 4C water (I suspect it'll try to track my heart rate, which would drain the battery at a faster rate). See where I'm going with this? In the words of the great @narcslatethelie, #SomethingsOff.
You can find the post on the next experiment here.