I was able to replace with this battery:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
however, I see that this battery shows as "currently unavailable".
If I remember well, I had to cut the
cables and solder the H50's connector to the battery, since the connectors did not match.
Battery works and
charger does charge the battery, however the battery indicator on the H50 never shows the battery as being full. It always shows it with a maximum charge of half full. It does last all day, though, as the old one did the it was at its prime.
Bottom line, I think that any LiPo battery of the same size (603048) and "about" the same capacity, should
work. YMMV.
Hope this info helps you out.