Hi I have seen that dji do a very expensive car charger now - but its not wise to use your own car battery for this kind of load a 12v leisure battery is designed to be drawn down and last must longer however this is besides the main issue I have. The phantom 2 battery is classed as 11.1v but when charged is more like 12.7v so could a 12v battery ever fully charge a 12.7v battery ? 11.1 volt battery = 3 cells x 3.7 volts (3S) so is the phantom battery 11.1v or 12.7v ? Answered my own question here .. Most LiPo/Lion cells are 3.7V nominal (4.2V max and 3.2V min) So the nominal reading is what is showing... SO can this video be on the mark (2 videos in fact) https://www.youtube.com/watch?v=CA1cWjFD1Cw I assume for a 5200mah battery for charging at 1C this means a charge amps of 5.2 ? So I would need a power of IxV 5.2 x 12.6v = 65 watts - I am thinking the mercury ex may not be up to this newer age of power supply. Or it simply charges at lower than 1C and just takes longer ? The above 1C charge rating would presumably take an hour ? at 2C or 10.4 amps x12.6v (should I use nominal figure or max V?) 131 watts power needed. at .5C 2.6 amps x12.6v = 32.76 watts but agonizingly 2 hours charge time ? Am I getting these rough figures right ? I could live with a 45 - 60 minute wait time. Is that possible from a 12v leisure battery..