For the last few weeks, I've been hooked on the new TV series Alone on the UK's Channel 4. In the show, 11 people are left to fend for themselves in the Canadian wilderness - away from each other, so they are completely alone.
Through the days or weeks, they try to survive with just a few basic bits of kit they take with them - an axe, a few fish hooks, a tarpaulin, and so on. Then, as they deal with the starvation, close encounters with bears, and the mental strains of being cut off from civilization, they film their every move. Each contestant is dropped into their new home with five cameras (mainly GoPros), and asked to film their every move from at least two angles.
The only visible communication they have with the outside world is a satellite phone - which they use to "tap out", when each in turn decides to give up on the challenge, leaving the one £100,000 winner.
But as the episodes tick over, the question I asked was how do they keep all their batteries charged? There is not a solar charger to be seen anywhere - and if you are making a major TV show, relying on sunshine in the extremes of Canada's Northwest Territories would be a terrible risk.
The answer, it turns out, is simply that the batteries are regularly replenished. Channel 4 explains "During their time alone in the competition, competitors accessed essential filming supplies such as memory cards and camera batteries using a drop box system (a waterproof box that was emptied and replenished at set times)."
The TV company also reveals that competitors also had to check in via text every day, and that they received a weekly medical from a production team's physician.
These same conceits are also used on the original American version of Alone, which first aired on the History Channel back in 2015, and which has just completed its tenth season.
One former contestant from Series 2 commented on this Reddit thread: "… as the season progressed (which meant more folks had dropped) we got more batteries and recharging stations (some batteries were rechargeable). They were pretty hands-off with us (S2) when they did the battery/SD card swap out. They went into my shelter, went through my Pelican camera case and did all the swapping out with me out of the way".
The drop-box system may seem to ruin the impression of the contestants truly being alone. But in the end of the day, it is a simple way of ensuring that the show can go on. Additionally means that the producers can take away memory cards during film, so they can check the quality of the footage, and make first edits.
Channel 4 is already looking for participants for the next UK series of Alone - if you think you have what it takes you can apply here. Details of how to apply for the US series on the History Channel can be found here.