As it turns out, Dell did decide to expedite shipping so I got in time to try it. BUT - they sent the same incorrect item - just the empower and car plug - no actually adapter. Just absurd. Then they wanted me to call fedex to arrange a return. I emailed them that I wasn't taking any more time on them - and they could email me a label - which they just did. I wound up paying for one-day shipping through Amazon to get a non-Dell adapter on the day or her flight(I have prime anyway - so it was just an additional $4. I bought 3 different adapters bc. there was no way to be sure which might work with dd's dell laptop (it's new enough that it's not specifically listed as a compatible laptop). Good thing I did. One item was not the appropriate item. One never came - and one arrived in a nick of time and seemed to be the right one - a Kensington car/air ac/dc adapter - that fit her laptop. Raven - thank you for that link. Sounds like a great program - unfortunately they left on the 27th. But I may look for something similar for my smartphone. I think I already downloaded an app that does that for the phone. Mike - I do know that there could be any type of plug (empower,car type plug or regular ac) - and that there may or may not be a plug - and it may or may not work. Of course, neither my daughter nor husband has gotten online to email me that they've arrived and are okay. Guess I'll find out soon whether it worked. Thanks. Lynn.

I found another adapter sitting around that is 12v 550mA and tried it out. It seems to be working fine so far. And yes, the fan is controlled by a sensor, so maybe that is why there is a range in the Amps. I'll need to crank up some tunes and test this setup out to see if it works properly. At room temperature the fan slowly spins, so if all goes well, it will speed up as the temperature rises and keep at a steady rate. One problem though is that the fan will be running as long as it's plugged in. I don't think the stereo gets hot when it's just sitting there, so for now I'll just have to unplug the fan or leave it running. Might hook up a switch eventually. It says it has a running life of 50,000 hours, which if I'm calculating right is almost 6 years. I guess I could just leave it running since the system itself probably won't last that long. Think it would be fine?

So called "adapters" aren't all the same, even if the output current matches. Some of these are simply a transformer and diodes - providing a very "dirty" and very approximate 12 volts DC. Some are sophisticated switching power supplies that provide a very accurately regulated voltage. Still others have special characteristics for charging particular types of batteries - AND, using the wrong one for this purpose can cause battery explosions or fires. The answer is to find out what the adapter actually does and what the device requires. With the number of surpluss adapters available the chances are good there is a cheaper one available than the "company" wants you to buy, and I imagine that the cost is the issue.

The only time I have been cautioned about something like this is with my Samsung tablet. The directions say to always plug the power cord into the tablet first and then into the wall, and to disconnect from the wall before disconnecting the power cord from the tablet. However, that cord has a more complicated connector to the tablet than the typical cord that connects into a laptop.