I have a hahnel on the way, I also picked up two newmowa ones based on a number of reviews online on their other products. If they are rubbish I will let you know
worst case, I have paid £17 for a USB battery charger and two small paperweights lol
---------- Post added 09-28-19 at 12:37 PM ----------
I just found another thread that mentions the newmowa. In a test it provided 2/3 of the shots than you get from the Pentax. That's fine. I got them so I don't run out of power when I go to Cadiz. The Pentax will be my primary battery, hahnel secondary and the other two charged just in case. As for the charger, it seems there is often an issue with regulation so shouldn't be used too much. This isn't a problem as I have my original. Happy days