Inverter

We are going wild camping tomorrow and will be using the inverter to power a seagate hard drive to show films on a dell laptop is it safe to power both of them on the inverter at the same time and how long will I get out of the leisure battery before it needs charged

How big is your leisure battery

It should say on the inverter what size it is, be careful though as you really should use a sine wave one to give clean stable power as electronic items are fragile with unregulated power.

There will be no definitive answer as to how long they will last running two items, but have you thought about a large memory stick which only needs pluged into the tv and no power supply

Your inverter will have a watt rating, for example I have one which is 300w. You can transfer from one to the other but you need to connect both to the pc to do it.