This type is a good choice.View attachment 305037
or something like this ? it says 3a but i guess its fine as long as its not less then 2 ?
Though whether or not there's enough left in the battery after three days to actually start the vehicle is another matter.5 volts at two amps is ten watts. A ten watt load on a 12 volt battery will be 10/12 amps (less than one amp). at 100% conversion efficiency that would be over 80 hours to drain the battery. So three days 72 hours, should be possible with reasonable efficiency. But the actual camera current draw may be less, most of the time.