Sorry I couldn't put together a blog with instructions , this will have to do. I know some of you all have already made your own using my idea , I would hope these pictures would be enough of a story so others can make their own. Well , I will add a few words The gravity flow BP is from SP Systems , you can order them from http://www.tessmanseed.com/index.htm out of St Paul Minnesota. I buy 3 at a time The pumps from Northern tool , I buy 4 at a time The batteries off the net , 10 at a time . Battery charger from http://www.batteriesplus.com/ , has alligator clips that easily connect to the tabs on the battery . Never use charger in truck , just change out battery , takes 10 minutes or less The metal plate or base that houses the battery and pump was made at a sheet metal shop . You can make one your self , Ace hardware sells small pieces of sheet metal that you can use , drill holes to adhere metal plate to BP frame . I used a drill to make a hole then a jig saw to make a slit for the velcro that holds the battery in place . Drilled two holes ( not 4 , even though the pump has a place for 4 bolts ) For 2 bolts to mount the pump to the metal base . In these photos , there is a ele switch to turn on & off the pump , I have made 20 of these ele pack back sprayers and only used a switch in a couple , I find there is no need for a switch. Just pull the wire off the battery if you need to disconnect it . There are no rules to making one , come up with your own design . Any questions ?