Hi All, Have purchased a 10W solar panel to trickle charge a Lead acid car battery. Using this as a test basis before I buy more panels to up the wattage. Am trying to find out if it is working. The panel comes with two adaptors: a) Crocodile clips b) Blocking Diode protected cigarette lighter plug. Testing the voltages before I plug it in using my multi meter. Open circuit (i.e. not attached to the battery I intend to charge) Panel receiving the same light (Consistent cloud covered day) 1) The voltage direct from the panel is fine across the crocodile clips. Essentially the voltage supplied by the panel. Measured 17V 2) Using the cigarette lighter plug adaptor with the panel. I measured 10V across the positive and negative terminals on the cigarette lighter plug. I thought these voltages should be much closer with the cigarette lighter adaptor reading 17V minus a small voltage drop across the diode? Am I thinking wrong here? Any insight will be appreciated.