How can I make these batteries work with solar and charge controller

WhittakerJ

Hey everyone, I'm trying to put together a solar/battery-powered water pump. The thing I am unsure of is how to make the batteries compatible with the charge controller. I currently have a  bunch of these batteries, 40 cell 36v. This is my 12v pump. I purchased this solar charge controller. But I think I may return it. I was thinking I could use a DC to DC buck converter to connect this battery to the solar charge controller? But I've never used one of these in a two-way manner. It's always been one way. So I'm not sure if this will even work? I also haven't purchased a panel yet. 

My goal is to have a USB charger for misc. devices as well as run this pump off the same setup. Hoping for some feedback. Thanks!

Jades

I don’t see how you go down from 36 to 12, and it sounds like there are a lot of unknowns and you want to be able to plug miscellaneous devices into it, so maybe a goal yeti or something like that is your best bet. I also don’t see why you’d be using a dc to dc to connect to a charge controller.