The Self-Powered Harvester Kit is a No Trade deed that can be obtained from the
PAAS. Possessing this deed enables a 'convert harvester' option on a deployed harvester, which will remove the power(but not credit) maintenance need of that specific harvester. Re-deeding or destroying the harvester will refund this deed. Three of these can be combined to be used on an Elite Harvester.
An alternate, and generally more successful, method of apply the deed is to: put it on your toolbar, mouseover the harvester, and use the kit via the hotkey.