No you don't as I didn't......but then again I don't "need" any of my Reos either.
These modules can read up to 25V but keep in mind that it must be wired properly for different voltage ranges. If wired in for 1S (1 cell) be sure to measure only 1 cell. For different voltage ranges it must be wired for 2S (series), 3S, 4S, & so forth. Don't ask me how I know. When I built my first one I was being stupid & started measuring everything (cognac's fault). I did measure up to 14V wired for 1S (just lucky probably) but after that it fried. Good thing I bought a bunch of them anyway.