Override to allow sunspot to return an array that can be used by Kaminari

sunspot_kaminari_support.rb

module Sunspot
  module Search
    class AbstractSearch

    private

      def maybe_will_paginate(collection)
        collection.instance_eval <<-RUBY, __FILE__, __LINE__ + 1
          def current_page
            #{@query.page}
          end

          def num_pages
            (#{total} / limit_value).ceil
          end

          def limit_value
            #{@query.per_page}
          end
        RUBY
        collection
      end
    end
  end
end

Dunno if someone is still using this "patch" to add kaminari support.

On num_pages the way you're doing the expression is returning an integer to ceil() and it doesn't returns the expected value.
You need to change to:

(#{total}.fdiv(limit_value)).ceil