It has been shown that scavenging energy from raindrop impacts has the potential as a power source for electronic devices and act as an alternative method of generating electrical power. In this paper an energy harvesting module is developed consisting of multiple piezoelectric devices which use impacts of raindrops to generate electrical power. The effect on efficiency of the module with non-rectified or rectified outputs of each device connected in parallel is investigated. Additionally, the voltage, power and energy were found for different surface angles, surface conditions and impact regions for single devices with a view to maximise module efficiency. The main findings of this work are that: a) a technique is found to identify the efficiency of the impact mechanism as the droplet interacts with the device and the efficiency of the mecheno-electric conversion mechanism due to internal losses in the device; b) values for the impact mechanism efficiency and the conversion mechanism efficiency are ascertained; and c) the optimum arrangement for a single device is determined. (C) 2017 Elsevier Ltd. All rights reserved.