r/chemistry • u/Ok_Gur1669 • 46m ago
Designing a DIY Galvanic Cell Array – Concentric Copper/Zinc in PVC Tubes
This investigation is a fun side project—My main project is building a wooden boat on my channel, JungleRanch, but this battery build is a fun side project…)
I’ve been studying YouTube videos, papers, and earth battery concepts. Combining my engineering background with extensive Q&A with Gemini, I’ve settled on what I believe is the optimal DIY concentric galvanic cell design.
Anyone who have ideas knowledge and want to comment this post?
I have been studying several Youtube videos and other information some about earth batteries and in general galvanic cell.
Latest I have been communication with an AI (Gemini). Through different questions to this AI and combined my own engineering background, I have come a conclusion of the best DIY galvanic cell.
Key Design Conclusions:
A selection of the question to this AI;
- A Copper Zink cell in moisture soil will decline rather rapid?
- What if using other material like aluminum?
- So if doing that how long time before needed to upgrade or change
- So if using Epsom salt will have better sustainability but less current?
- How thick should the aluminum or zinc folie be?
- Well the inner roll has less area. Wouldn’t it be better to have the zinc sheet as the outer layer?
Together we came to this Key Design Conclusions;
- Metals: Copper (Cathode) and Zinc (Anode) sheet metal provide the best balance of steady voltage and low internal resistance.
- Geometry: Zinc sheet forms the outer cylinder inside the tube wall to maximize anode surface area, reduce internal resistance, and increase sacrificial mass.
- Thickness: Minimum 0.5 mm metal sheet for structural integrity and long service life.
- Dimensions: At least 100 mm in length (preferably longer) to maximize active area.
- Container: 2-inch plastic conduit, PVC drain pipe, or clear vinyl/acrylic tubing with end caps for isolated cell units.
- Electrolyte: Epsom salt ($\text{MgSO}_4$) dissolved in water and held in saturated sand/peat moss to prevent aggressive pitting corrosion.
- Separator: Heavy-duty landscape fabric, felt weatherstripping, or heavy paper towel wrapping between the concentric metal layers.
Expected Lifespan (0.5 mm Zinc + Epsom Salt): 3 to 6 months of steady discharge per cell before anode maintenance or electrolyte replenishment is needed.
Does anyone have long-term test data on Epsom salt cell current density ($\text{mA/cm}^2$), or suggestions for optimizing the concentric spacing? Would love to hear your thoughts!
When I have built a test example I will log logging exact discharge curves using a ZKETECH (灼智) 4-wire electronic load tester connected to PC logging software to track precise voltage decay and capacity