From old laptop battery packs that refused their service in their original environment, I have taken a number of lithium round cells. A few (!) Were really broken (0V), others only empty (voltage below 3.5V), but most of them had 3.7 ... 3.9V still acceptable voltage values. Since the shop at the DC power supply is a bit tedious, I was looking for a cheap charger and this award values found. First Impression: solid case that has even survived the probably very stressful transport from UK without damage - the carton was badly deformed. A manual was missing just as appropriate instructions on the box. The accessories consisted of an English power cord with quite shaky Euro adapter - after all (the cable can be replaced with any German Euro-Cold device connecting cable). Acquired by me Model WF-139 has other than a CE mark no approval mark, so it must decide for himself whether he wants to use such a thing on its own premises. I have, also because of the reports on this "smoldering and stinking" failures, first of all open the unit. The device (platinum imprint 2013/11) is constructed properly and clearly, the SMD solder joints meet the requirement for industrial consumer goods. The network side is with a proper fuse (which can be found in this price range today only very rarely) protected and has sufficient safety distances to the accessible metal parts. Unfortunately, the actual power supply of a primitive self-oscillators, similar to the first halogen transformers 20 years ago, but notwithstanding optically fed back by the former technique and thus stabilized. The 12V socket is "battery friendly" integrated via an integrated StepUp converter and the actual charging electronics consists of two completely independent circuits. At idle, with no battery or on a single charge, the green light, during charging, the lamp flashes red. Loading to 4.2V, ie to the limit of what is physically acceptable: the battery is then true sense, but the life is already reduced. Therefore, the batteries should not remain a long time in the charger after charging Zykluss (green). The charging times given are nonsense: if I have a battery with 2Ah capacity and this charge with 450mA, then take to charge 2000mAh / 450mA, ie at least 4,5 hours - without taking into account losses and excluding that the charging current is always lower, each full the battery is. Thus, therefore, the terms given in other reviews 8 ... 9 hours to charge realistic. The device is in the first phase quite warm (you can barely hold in hand), the batteries are barely lukewarm.
Resume: The unit is worth its price - for users of the dangers when handling the battery are aware. Anyone - certified - emphasizes security, but should leave it alone.
