In seat power - Help please.

I will be flying next year with VS from LHR in PE to LAX. As I have always been PE, LGW to MCO and never had in seat power I was wondering about using the seat power.
Am I correct in thinking that you can buy converters to convert the empower socket to a standard car DC style outlet then I can use my existing car power leads for my laptop and MP3 player. I have seen the converters on ebay and magellens at about 10, has anyone used one and do they work ok.
I have checked the VS web site and my Laptop / MP3 player is not listed on the one's they have onboard for you to use in flight.
Many Thanks
Am I correct in thinking that you can buy converters to convert the empower socket to a standard car DC style outlet then I can use my existing car power leads for my laptop and MP3 player. I have seen the converters on ebay and magellens at about 10, has anyone used one and do they work ok.
I have checked the VS web site and my Laptop / MP3 player is not listed on the one's they have onboard for you to use in flight.
Many Thanks