Board Thread:Questions and Answers/@comment-13413401-20130901211033/@comment-216.118.151.154-20130907115525

That's why the batteries in the filters/retrievers are fully drained/charged. The machines will only pull the batteries out of the battery boxes once their data values are exactly the same as the batteries inside the machines (so even though the filter is trying to pull out a battery every 2 seconds, it will only pull it out once the charging battery reaches a damage value of one (fully charged))