Absorbency testing is used to determine the percentage of ZnCl2 or NH4Cl solution absorbed by a hydroponics gel (HPG). It is found that the absorbency of ZnCl2 or NH4Cl solution decreases with increasing solution concentration. The conductivity of ZnCl2- and NH4Cl-HPG electrolytes is dependent on the solution concentration. A mixture of salt solution with HPG yields excellent gel polymer electrolytes with conductivities of 0.026 and 0.104Scm−1 at 3M ZnCl2 and 7M NH4Cl, respectively. These gel electrolytes are then used to produce zinc–carbon cells. The fabricated cells give capacities of 8.8 and 10.0mAh, have an internal resistance of 25.4 and 19.8Ω, a maximum power density of 12.7 and 12.2mWcm−2, and a short-circuit current density of 29.1 and 33.9mAcm−2 for ZnCl2- and NH4Cl-HPG electrolytes, respectively.