If there is a problem with the connection of one panel in a series, the entire circuit fails. Between the two simplest types of mismatch considered (short circuit current mismatch or in open circuit voltage mismatch), the short circuit current mismatch is more common, as it. Proper MC4 Connections Prevent System Failures: Loose or improperly crimped MC4 connectors are the leading cause of series string failures. Using the correct crimping tool and following manufacturer torque specifications prevents arc faults, power losses, and potential fire hazards in 2025's. In a series connection, you connect the positive terminal of one solar panel to the negative terminal of the next panel in a string. The entire string of series-connected modules is known as the PV module string. Imp is the maximum power current.