It does not work!
It appears to charge itself, but it will only charge another device for about 5 minutes before dying. I need to return it. Do not recommend.

Very Pleased - Good deal for the price
I bought two of these to extend the taping time for my camcorder. Rather than buy enough batteries specifically for my camcorder (at $56 each)to tape six hours worth of youth football I bought the Black and Decker 100 Watt Power to go. I actually bought two but I havent needed to open the second one because the first has performed so well. I have run a myriad of small items off of it so far and it has performed very well. It does get warm during use so make sure its out where it can breath. My only complaint is that the charge status lights do not give a good representation of when the battery will stop working. It could be still on four or five bars when it quits. It also takes several hours to reach full charge so be patient before you test it out.

Summary - For the low price and versatility I am very pleased with this product.

It came through for a unique situation
I purchased this device to power a low voltage digital music synthesizer for use on a trailer in a local parade. There was no room to use a generator. In tests this power supply was able to power this device for 1.25 hours before the battery level started to drop. The parade last 45 minutes so the power was more than adequate. This will be great to use for practicing where there is no electricity available. I recommend it highly.

works great for small hadheld electronics
charges ipods cell phones and the like no problem. I would never try to run a laptop or electrical appliance of off it.

Not too shabby
As others have noted, this isn't necessarily meant to power your laptop. It can, if it doesn't drain more than 100 watts (80 watts continuous). I get an extra 45 - 60 mins out of it on my laptop. It is, however, great for charging cell phones, mp3 players, etc. I already have a smaller model that I use for that purpose. I'm actually using this thing to power an aerator in a bucket of water, to keep the fishing bait alive. Works all day without a problem. My father was complaining about only getting an electric, non-battery powered aerator, and I suggested we try this B&D battery. Works like a charm!

In a nutshell, this can be used with a laptop in a pinch. It works much better with lower drain devices, however. If you battery just died, and you need to get a document off of it ASAP, this little device may save the day. Need an extra 4+ hours of battery life on your laptop? This probably is NOT for you. Get a spare laptop battery that is made for your computer.