I’m doing my first IM on Sunday and it has occurred to me that I’m not at all sure my 920XT will last the race.
If I was fast I’d probably be okay but I’m not. I think I should be able to get under 13hrs but it remains to be seen, could be 12.5 or if I really blow up in the run (and the forecast is hot and humid) it could be 14hrs.
I should have tested the battery and I’m currently doing so by running it and wearing a HR strap but it’s not entirely equivalent to the race as I’m doing it a few hours at a time when I’m outside or beside a window and I’m not using the speed/cadence sensor on the bike etc.
What have all of you found to be the battery life of the 920XT?What setting do you use to maximise it?
I’ve turned off GLONASS and I have the backlight timing out after just a few seconds.
Does the recording frequency have any impact on battery life. I’m guessing it only impacts memory so every 1s should be okay?
Anything else I should consider?
The 920XT is only a few months old. I had a 910XT before that and I still have it. I use the 910XT as a bike computer now (using the quick release) and the 920XT for everything else. If the 920XT is not going to last the duration of the race, I could turn it off for the bike and just use the 910XT. Then turn it back on for the run. But I’d prefer to use it for the whole race if I can so that I have easy access to my total elapsed time and of course I’ll have a single data record for the whole race.
I’m curious about this too. Good call on the backlight - apparently I left mine either in too long of a timeout or completely on, because mine died at mile 22 of the marathon at 12 hours last year. I’ve got a power meter paired to it now, so I’m sure that won’t help battery life.
So I have some comments, based from direct and indirect experience:
Direct: I used an F3 for an IM and although it wasn’t 13 hours extrapolating the battery consumption predicts about a 15 hour lifespan. It is also generally accepted that the F3 has less battery capacity than the 920xt. (GLONASS off)
Indirect: I know several folk with 920xt’s have finished longer than your predicted time and had some capacity left.
Direct: F3 consumption rate is not exactly linear. Predicted battery capacity from training (<4.5 hours) was not an accurate predictor of long course battery consumption (the latter being more efficient, reason unknown).
But most of all, good luck. I think its important to put this stress out of your race. I don’t think that swapping devices is a smart idea; its more things to do during the race, and more opportunities for error to cause a deviation from your race plan. If your battery runs out, it’ll do so in the final stages of your race—where the data will have the least value (or at least when you have the most diminished ability to do anything about any deviation from your race plan). You can always ask a spectator for the time and do some simple math…
Answer = maybe. Here are my 2-3 experiences using my 920 in IM length races.
Planned 13 h finish, actual 14h finish (several flats on the bike, hugely windy day). Whole race timed only with the 920. Don’t believe I had glonass on. Left bluetooth and wireless on b/c it never occurred to me to turn it off. Had recording set so PM values were less wonky (might be 1 sec, can’t remember). Turned watch on while putting wetsuit on, watch died maybe 15 min before I finished. Spent loads of time frustrated by the low battery warning message leading up to that moment. (Wrist optical HRM died before bike split was completed.)
Planned <13 h finish, actual 11.5 h (down current swim, flat but still windy bike course, and my best executed race, ever). Bluetooth and wireless off, PM unpaired from 920. Power recorded on 520. Devices pulled from charger race morning. Still got low battery warning on 920 toward end and finished race with watch on fumes. Wrist based HRM (turned on at start of bike) still crapped out early into run segment.
Experience 3 was a long duathlon, 10.5 h finish. 920 pulled off charger race morning and possibly left on as a watch for the 2-2.5 h of pre-race. Using a chest strap. Forgot to turn bluetooth and wireless off. Different PM now was still only paired to the 520. Fucking watch died maybe 2 mi into R2, so got like 7.5 h of race recording life out of it.
All told I am not a fan of the 920 or either of the two optical HRMs I’ve had (Soche, Mio). I’ve since done a factory reboot of the 920 but won’t know whether it’s helped b/c I’ve since picked up the more-comfortable-for-my-small-wrist 735. I’ll try to turn HR off for the bike leg and hopefully get enough battery life out of it for my IM next month.
ETA - If you have a PM, realize that pairing between the 920 and the power meter may not work the same way as it did with your 910. I had zero problems with my 910 in either PM pairing or battery life. I’ve had several headaches with the 920 which pairs terribly with my Stages PM if the 920 is on my wrist. Works fine if the 920 is on an out front mount, but I realize that isn’t your plan. I’m told the 920 does play nicely with other PMs, so hopefully you’ll never come across this headache.
There is obviously a lot of variation by the looks of it. My experience through two halfs and one full is that you should have lots of room for a 13h race. I turn BT off, use 1s recording, and leave everything else as it came (backlight etc.). I have HR and power paired to it. It might not be linear so tough to say for sure, but I would conservatively estimate I had 15h of life when I did the full and possibly a chunk more.
It sounds like I might be okay then but no guarantees. I have suffered dead battery on a couple of training sessions when I forgot to charge it beforehand and as far as I remember I got about an hour after the low battery warning started. I’ve been using mine with both the backlight and GLONASS always on while training. After all, most of my training during the first few months I had it were in the dark. I only thought to turn both off last week. I have also turned off WiFi and I don’t use bluetooth.
I’ve normally been using the new Garmin triathlon HR strap (black strap, blue bezel on the electronics) and that’s what I’ll use for the swim and run. I got a Scosche Rhythm+ a couple of weeks ago which I’ll probably use for the run. I find chest straps fine for the swim and on the bike but really annoying when I run. I think it’s because of my triangular physique it always feels like it’s going to slip down and on several occasions it has in fact ended up around my waist during a race. Same problem with the old classic strap that came with my 305, the premium strap I got with the 910, the Polar strap I replaced it with and the current Garmin strap. Making them tighter or looser doesn’t seem to make much difference. I have noticed the Scosche is a lot slower to respond and sometimes the HR wanders off to values that I know are wrong but it usually finds it’s way back again. It’s been more reliable for me in dull conditions or at night so maybe I’m not getting good enough contact to exclude daylight on bright days.
The Scosche and Mio optical sensors are both rated for only about 7 or 8 hrs. I already knew that when I got the Scosche so I wasn’t planning to use it for the duration of an IM. If I can get it to work more reliably it’ll be perfect for shorter Olympic and HIM distance races.
I think I’ll just assume the 920XT will last the duration. If it doesn’t it’ll be mid run anyway and I can pace on effort for the remainder. To be honest, HR is unlikely to dictate my pace anyway at that stage.
P.S.
My then HR strap failed early on the bike during a 70.3 I did last year so I did almost the entire race on perceived effort alone. Given I refer to HR all the time for pacing during training I was surprised how well I managed to pace myself in that race without that crutch. It’s possibly the best paced race I’ve ever done. I never blew up but the tank was empty just as I hit the finish line. Perhaps I shouldn’t worry too much about the battery dying!
… so I did almost the entire race on perceived effort alone. Given I refer to HR all the time for pacing during training I was surprised how well I managed to pace myself in that race without that crutch. It’s possibly the best paced race I’ve ever done. I never blew up but the tank was empty just as I hit the finish line. Perhaps I shouldn’t worry too much about the battery dying!
Yep, nothing beats being well-trained. Ideally the devices wouldn’t be needed come race day (I’m most interested in after-the-fact metrics). But I’d rather race with nothing strapped to my body than carry along stuff that does nothing b/c it’s all dead - that frustrates the bejesus out of me. As does being reminded several times by a prompt indicating battery is low. Nothing I can do about it in a race but be irritated, and the prompt keeps prompting… Particularly on the 920 which has to buzz/vibrate to announce every emotion it has. (Seriously not a fan of this watch.)
I would be careful with leaving the watch in the charger for long periods of time. Once it is 100% charged the actual charge starts to go down, even though it continues to show 100%. So really you want to take the watch off the charger once it reaches 100% for maximum charge.
I would be careful with leaving the watch in the charger for long periods of time. Once it is 100% charged the actual charge starts to go down, even though it continues to show 100%. So really you want to take the watch off the charger once it reaches 100% for maximum charge.
I finished in 13:02 and had a decent amount of battery left (don’t remember the percentage, but >10%). I used the garmin HRM and also vectors as my PM. My settings included what you said with wifi and bluetooth off.
I have a run alert. What I want to know is will the alert still work if I turn off sound and vibration under system settings. I want the run alert, don’t want all the “Hi! I’m connected. Help! Phone disconnected” nonsense alerts.
Playing devil’s advocate here, why do you NEED the full race on one watch? I know it’s nice to look at it after the race, but after that, what does it really do for you? It’s three different sports, so the data doesn’t play well together, and it just adds more things to remember to do on race day - forget to hit the transition button when you leave T2 until you’re a mile into your run? whoops. I could see total elapsed time being nice during the race, but there are race clocks all over the place for that purpose.
I raced with a 910xt for a few years, and the timex triathlon watch before that, but in my last IM, I went with no watch on the swim, Garmin 510 on the bike, and 910 for the run (put it on as I ran toward run start). I didn’t have to worry about hitting start while treading water when the cannon went off or about a button getting pressed during the swim. I had a nice big screen for my bike power/hr/cadence data and nothing on my wrist. And had my pacing data on the run. In the end, IM gave me my total time and time for three segments + transitions.
Turning sounds and vibration off will kill the run alerts too, pretty sure.
I think you may need to turn off individual options to stop other vibrations- there is an option about connection alerts in the BT menu, isn’t there? (There is on fenix 3)
Similarly if you don’t want alerts on the bike, you probably have to turn off auto-lap there…
I don’t think you can leave the general vibration on and yet flip a single kill switch to stop all but run alerts.
I would be careful with leaving the watch in the charger for long periods of time. Once it is 100% charged the actual charge starts to go down, even though it continues to show 100%. So really you want to take the watch off the charger once it reaches 100% for maximum charge.
Have you got some data to support this? Interested as mine lives on the charger when not in use. Can’t say I’ve noticed any change to the battery life.
I have a run alert. What I want to know is will the alert still work if I turn off sound and vibration under system settings. I want the run alert, don’t want all the “Hi! I’m connected. Help! Phone disconnected” nonsense alerts.
If you don’t want bluetooth alerts, turn off bluetooth.
If you don’t want wifi alerts, turn off wifi
Work through the services and alerts you want and enable/disable as required.
Can’t see the need to have any distance alerts during an IM as the distances are usually well identified. So why not turn them all off anyway?
it always feels like it’s going to slip down and on several occasions it has in fact ended up around my waist during a race. Same problem with the old classic strap that came with my 305, the premium strap I got with the 910, the Polar strap I replaced it with and the current Garmin strap. Making them tighter or looser doesn’t seem to make much difference. I have noticed the Scosche is a lot slower to respond and sometimes the HR wanders off to values that I know are wrong but it usually finds it’s way back again. It’s been more reliable for me in dull conditions or at night so maybe I’m not getting good enough contact to exclude daylight on bright days.