Just to be safe, since batteries are new, remove all cables and check each battery for voltage. You state that sometimes it will operate correctly, seems to be a failing connection. Verify all battery connectors are crimped tight and make a good connection. With new batteries you can have a connection problem if not cleaned first. Where the estop switch is at, check all wires and connections are tight. Have seen issues with failed crimps on male slide on connectors. Good Luck