How to Repair Thin Film Solar Cells

What You'll Need
Extension ladder
Replacement thin film solar laminate
Copper wire
Solder (containing 2% silver or conducting epoxy)
Roofing adhesive
Roofing screws
Drill or screwdriver

Thin film solar cells are cheaper and more convenient to install than conventional silicon wafer crystalline solar panels. However, the thin film laminates are more prone to manufacturing defects and operate with a lower efficiency. The benefits often outweigh the costs, and if your system has a damaged cell you will want to replace it as soon as possible. Always take time to work safely with electrical circuits. Inspect your photovoltaic modules, inverter, battery, and balance-of-system equipment for damage or bad connections. Replace the failed components to restore the system to its intended output.

Step 1 – Work Safely

Since your thin film photovoltaic laminates are most likely installed on a roof, choose a day with mild weather to work on them. Brace your ladder at distance from the wall equal to ¼ of its height. Use of a personal fall arrest system is recommended. Shade the solar panels when you are working with them so they are not actively producing electrical energy. Disconnect the solar circuit from the rest of the house and the battery back-up as a precaution. Only energize the solar circuit while testing to locate the failure.

Step 2 – Inspect System Components

Inspect the wiring and connections at all terminals and junction boxes. Corrosion and oxidation are common problems, especially with outdoor wiring. Replace or repair wiring as necessary. Inspect the laminate for mechanical damage from hail, debris, or vandalism. Thin film solar cells are just a coating of silicon applied to a sheet of glass or stainless steel. With traditional silicon wafer solar panels, you could replace individual modules by cutting out the damaged cells and installing a new cell with solder or epoxy. With thin film laminates, it is more efficient to replace the entire damaged sheet. Obtain replacement laminate with output ratings equivalent to the original installation material. A dealer or contractor can recommend a product.

Step 3 – Test Cells

If there are no obvious signs of damage there might be a manufacturing defect or other flaw with the semiconductors. If the cells are wired in series as a daisy chain, it will be easy to disconnect individual sheets. Remove the sheet’s shading and test the output voltage and amperage against its ratings. If you find an obviously defective cell mark it for removal and replacement.

Step 4 – Replace Cells

Obtain a suitable replacement laminate in the required dimensions. Disconnect the old panels from the system by disconnecting the wires, then unscrewing them or scraping them off with a crowbar and shovel. Lay out the new sheet and glue or screw it into place. Wire the new panel to its neighbors in the same manner as the original installation. Reconnect all the system components and check the output.