$16 alternative to 12v bed outlet

I'm about to buy one of these to use for camping. My DC does not have an accessory 12v in the bed. With this one you plug it into the 7 pin trailer plug and it becomes a 12v "cigarette lighter" type outlet. Anybody tried it or have some other idea before I spend all this money?
http://www.tweetys.com/7-pin-to-12-volt-dc-adapter---have-a-12-volt-outlet-at-your-hitch.aspx

 

Cool idea, I think that I will purchase one too.

 

How did this adapter work? Does the truck have to be on for it to be powered?

 

Anyone have any input on this? Thinking of ordering it to use on my camping trip coming up this weekend.

 

I'm not sure I'd run anything requiring too much power out of that. Not sure the wiring can handle much.

 

I plan to run my power inverter through that. Is that asking too much from it?

 

I don't think it's on unless the truck is the fuse is 30 amp so there is a good bit of power there. It's used to charge a camper battery so it makes sense for it to be off when the truck is not running so you won't end up with a dead truck battery. Fused at 30 amps it's good for a max of 360 watts @ 12 volts assuming 90% efficient that's good for 324 watt inverter max .