Board Thread:Questions and Answers/@comment-99.9.136.46-20130721021256/@comment-5627887-20130721134839

You can put Overclock Upgrades and Energy Storage Upgrades into a Charging Bench (HV would be the best one) which will store extra EU up and increase the speed it recharges tools and LapPacks etc.

I would advise against leaving any tools or items in the charging bench though, we have had times when the server has crashed, that wiped any items that were left in a charging bench, better to have items that are charged output to a chest for safekeeping.