The rear panel of the Univeral Charger is mainly constituted by the PCB that is the panel itself. All the millings are realized using a standard PCB realization service and all the files for this realization are included in the manufacturing files. The millings presents on the rear panel are for air inlet and outlet, for 4mm socket (power supply) and for fan cooler fastening. The 4mm type connectors used are quite large but the millings are compatibles with more cheaper types (FARNELL 871760 and 1176427) and with some other unbranded types. The fan cooler is a 70mm, 900 liter/min (31 Cubic Feet Minute) from SUNON the KDE1207PTV1, this type has a tickness of 25 mm. In case of less power dissipated (discharge current of 5-10 Amps) is sufficient a 60mm fan cooler more easy to find and cheaper. In case the internal heat sink has a depth greater than 30mm is sufficient to find a fan cooler with a total tickness of 15 or 20mm. The best performances are obtained when the fan cooler air outlet (typically the face with the printed marks) in direction of the charger external side (see figure).