The AA Solar Panel Car Battery Charger plugs directly into the EOBD plug socket inside your vehicle (standard on most cars, petrol from 2001 and diesel from 2004). The solar charger will trickle charge and maintain a 12V vehicle battery while the vehicle is parked by converting light energy during daylight hours into 12 volts DC. The unit is maintenance free and will protect the battery against the discharge process that occurs naturally within a lead acid battery. The charger is easy to install and is fitted with a flashing blue LED light to indicate charge. There is built in discharge protection as well as reverse polarity protection and the Solar Charger will not overcharge your battery. The 'THINFILM' technology allows a wider spectrum of natural light to be absorbed, meaning the unit can still generate electricity under cloudy winter conditions. This technology also enables the solar panel to handle the intense heat of the summer sun with little power loss due to the rising temperature. Direct battery clamp style connector clips with a generous 2.8m connector lead are also included as well as four suction cups to allow easy installation in most vehicles. A seven page user guide and quick start guide are included to give the user easy to follow step-by-step instructions. Four reasons to own an AA Solar Panel Car & Caravan Battery Charger: Batteries Naturally Discharge - Automotive batteries naturally discharge when not in use. Modern vehicles have a small but constant battery drain - Modern vehicles can now have upwards of 30 body control modules (computers), plus alarm systems, immobilisers and lock monitoring. These units all consume valuable electricity from the battery (up to 0.02 of an amp per hour). This means that over the course of a week or two with no or little vehicle use the battery can become discharged. Battery life is shortened if it is not kept charged - A 12V battery that is not correctly maintained above 12.4V can suffer from sulphation. Sulphation is the number one cause of battery failure, something not covered under warranty as it is not a manufacturing defect. Peace of mind - Vehicles that are used infrequently or do short trips are prime candidates for discharged batteries - meaning you will need a new one!!Please note: the charger can only be used while the vehicle is parked and off. It is not waterproof and should not be left outside. Specification: Peak Power Output: 2.4 watt, Peak Volts Output: 12.7 volts, Optimum Working Current: 0.13-0.2 amps.