One of the reasons for choosing Dewalt equipment was that an official 12V charger was available, however, the device is poor quality.
2 x 2AH batteries were charged from a LiFePO4 Solar system from empty. Both charged fine, and were useable. However, once the batteries were drained, they would not charge at all, either via this charger or a mains charger. Luckily the batteries were under warranty and I was able to get replacements. This is pretty poor as the batteries were in good condition. A third battery that was bought at the same time as the first 2 has never been charged from the Solar System, and it is still in good condition a year later. I don't understand how it could have broken them, as the voltage was never over 14V.
User:Chewie: Not all 12V lighter plugs are the same
Although 12V Cigarette Lighter plugs and sockets should be able to take 20A @ 12V no problem, it seems that cheaper ones can only cope with 8A. If this is the case, usually the spring that holds the fuse and positive (middle) terminal gets too warm and melts into the plastic (example).
Better quality ones seem to have copper springs instead and are made of a harder shiny plastic. If a rating is not mentioned by the seller, expect it to only cope with 8A