Apple Watch battery life for Backyard Ultras
An old Series 7 got me to 20 hours on a single power bank. The fix is dead simple, but it only works if you build a system around it.
My Apple Watch is an old Series 7. The battery is not what it was. With full tracking running, heart rate and GPS on, I'm getting somewhere around five to six hours of runtime before it needs attention. That's not a lot in the context of a race that might go twenty-plus hours.
The obvious answer is a newer watch. The Ultra 2 will run for about 60 hours in low-power mode, which changes the equation entirely. But if you're not ready to upgrade, or if you're using an older model and want to get more life out of it, there's a straightforward method that genuinely works.
The lap charger method
Every time I come into the tent at the end of a loop, the watch comes off. It goes straight onto a charger that's plugged into a power bank. That's it. While I'm recovering, eating, sorting my kit for the next loop, the watch is getting a top up. Typically seven to ten minutes, depending on how long my rest is.
Seven minutes of charging per hour sounds like it wouldn't move the needle much, but the cumulative effect is significant. You're not trying to charge from empty. You're topping off a battery that's only dropped a few percent during the loop, and keeping it in a range where it can keep running indefinitely. I got to 20 hours at my last race and the battery was still going.
You're not trying to charge from empty. You're topping off a battery that's only dropped a few percent, and keeping it in a range where it can keep running indefinitely.
The part people get wrong
The charging itself isn't the hard part. Remembering to put the watch back on before you leave the tent is.
At hour fourteen, your brain is not reliable. You're operating on reduced cognitive capacity and the last thing you want is to be three kilometres into a loop before you realise your wrist is bare. So the method needs a system behind it, not just good intentions.
What I use is an in-tray and out-tray setup at my tent. Everything that needs to come with me on the loop goes into the out tray when I arrive. The watch goes into the out tray once it's done charging. Nothing leaves the tent except from the out tray, and the out tray has to be empty before I go. That means the watch is in the same category as my water bottles and my headtorch: things I physically cannot leave without because they're sitting right in front of me.
It sounds overly organised, but at 3am it makes all the difference. You're not remembering to grab the watch. You're just clearing the tray, the same way you do every loop. The habit carries you when your mind can't.
What you need
A power bank with enough capacity to run a charger for 20-plus hours, a short Apple Watch charging cable, and somewhere to set it up in your tent that's easy to reach and hard to miss. That's the whole setup. The power bank doesn't need to be large because you're only running a watch charger, not a phone or a laptop. A small one will last the whole race.
If you're running an older Apple Watch and wondering whether it can survive a long Backyard Ultra, the answer is yes. You just have to treat charging as part of your loop recovery routine, the same as eating and sorting your kit. Build it into the system and it takes care of itself.