After a server restart this morning all the batteries I had connected to portable lights are gone. Five of the batteries were car batteries and two were truck batteries. I have been playing on a private server hosted on a spare PC for about four weeks and have restarted the server many times without this issue. There are no other players that could have taken the batteries.

Both ADA vehicles and all other persistence items (tents, generators) remained after the restart, the batteries are the only item that were affected.