Jan 242017
 

These UHF portable radio sets are good value, [I am obtaining some for use by the janitorial and maintenance teams at work] but the supplied mains chargers aren’t the safest design – and like most similar chargers they also cook the accus if they are left on charge constantly which often happens when these sets are used by less technically minded endusers.

Update: Newer versions of this radio sold on Amazon are now supplied with a desk charger with a USB plug; it seems Baofeng have been monitoring the various comments from European users (and their modifications to the chargers) widely posted on blogs and social media (fair play to them!)

This is of course much safer and can also be used with any suitable USB power supply including cigarette lighter adapters for vehicles, but there are still a fair few units being sold with the mains powered desktop charger as well as many others in regular use worldwide.

You can also get better 6 unit chargers from HongKong which have a separate low voltage PSU (similar in size to a laptop charger) that connects to the desktop unit but in the meantime I investigated and modified one of the chargers I already have to make it slightly safer – a fiddly and awkward job due to the way this cheap charger is constructed.

ATTENTION: Don’t try this unless you are confident with working on mains voltage equipment!

Below are some pictures showing whats inside, a very simplified explanation of how this kind of charger works and why changing the cable is a good idea (I also used a better plug with a 5A fuse). The good news is that it all worked when I put the case back together (I definitely wasn’t going to attempt testing it with the live PCB exposed), and the output voltage at the terminals was correct (compared with that of an identical unit)

overview of SMPSU repair & operationoverview of SMPSU repair & operation