Lenmar is, to the best of my knowledge, a reputable manufacturer of aftermarket batteries.
I bought a DLPBLB13 battery as a 2nd battery for my Panasonic G2, charged it up, put it in my camera, checked for a few seconds to make sure it worked, and went off on a day trip, unfortunately leaving my original camera battery (Panasonic DMW-BLB13PP) home. When I went to use my camera, about 12 seconds after I turned it on, it complains "THIS BATTERY CANNOT BE USED", locks up for a little while, and shuts off. I had to give up shooting with the G2 and use my old point + shoot instead -- grr.
Now what should I do? Has anyone dealt with Lenmar before? I either want my money back or a camera battery that works.