In conclusion, this study provides a strong proof of concept for the use of low-cost optical multi-wavelength sensors in VRFB diagnostics, paving the way for more accessible and scalable solutions in energy storage applications. The experimental results offer valuable insights into the system's limitations, identifying challenges such as spectral distortions and channel overlaps, which are inherent to low-cost sensors. These findings underscore the need for further advancements in sensor design, aiming in particular to mitigate such distortions and incorporate self-calibration strategies. Furthermore, the channel optimization study provides an effective framework that can guide the design and development of next-generation, low-cost optical sensors tailored to VRFBs and other energy storage applications.