In this work, we maintain the cost-effectiveness of these systems while achieving robustness comparable to that of continuous UV-Vis spectrometers. In particular, we present a low-cost discrete absorbance measurement system, designed using a multi-channel optical sensor, a LED light source, a polymer microfluidics chip and a Raspberry Pi . The rest of the components are 3D printed, amounting to an approximate total cost of € 150. To verify the system's ability to measure both the SoC and the concentration, we measured a total of 66 samples with known SoC and concentrations (ranging from 1.21 to 1.82 M). We then applied the same calibration procedure outlined in our previous study based on a deconvolution method. For details on the calibration algorithm, the reader is referred to our prior work for further clarification.