No idea if this is what they meant, but it’s plausible that client battery usage goes up when connected to Tailscale using an exit node. Suddenly, a lot more traffic has to be processed in userland, on the CPU. Ordinary internet transit might be offloaded to the kernel or hardware such that it’s more battery-efficient.
Then again, that begs the question of what you’re heavily using exit-node-routed internet links for that Tailscale’s battery draw is noticeable. Most network-intensive internet tasks draw way more power to drive whatever the application is, such that VPN overhead is a rounding error.
You’re using a battery powered device as an exit node?
No idea if this is what they meant, but it’s plausible that client battery usage goes up when connected to Tailscale using an exit node. Suddenly, a lot more traffic has to be processed in userland, on the CPU. Ordinary internet transit might be offloaded to the kernel or hardware such that it’s more battery-efficient.
Then again, that begs the question of what you’re heavily using exit-node-routed internet links for that Tailscale’s battery draw is noticeable. Most network-intensive internet tasks draw way more power to drive whatever the application is, such that VPN overhead is a rounding error.