You may want to know your audience and their discussions and contributions toward the Yuneec platforms. Many on this site have strongly supported the Yuneec platform, and yes over time have experienced enough historical reference to express both positive & negative. Many would relish Yuneec success, that depends on Yuneec's offering and support to the End User/Buyer and the consumer confidence to purchase... that hasn't been provided consistantly by Yuneec and results in the consumers expressing.
You might want to examine the H920 threads... particularly the battery discussions. To state
@PatR as "Trolling" on a subject he's personally exhausted hours of time evaluating, testing and experimenting with several combinations is a bit off-key.
You suggest we try other areas for battery sources. Again, a short search within the H920 section will expose many attempts to contact battery sources and even a few events checking on the possibility to custom make for the 920. The 920's battery bay is a limiting factor to locate ample cells.
The OEM 920 batteries aren't even a consideration, they are either old stock or poor quality... that has also been displayed & discussed exhaustively.
To revisit a few other points: my experience with Yuneec support is poor... phone & email. I've actually had better success with Yuneec UK side. Much better with other companies: Autel, PowerVision, and DJI.
Support for the H520 has fallen short and very slow to evolve. I personally see no reason why the H520 hasn't obtained the features of the Plus and additional at the price of platform. Providing 3rd party support is minimal to null, that offering would be beneficial to the H520... a closed market in professional platform won't succeed. Yuneec market share isn't gaining in my observation, and that isn't the consumer variable, that is Yuneec. That said, no one on this forum is wanting the brand to fail but also not wanting to see minimal attention toward the model prior to news of launching a new model. Several have left Yuneec driven by project need or project requirements and Yuneec isn't on many Companie's preferred lists. It should "at least" be on the list of supported platform and it's not... again, a Yuneec issue not the consumer. Consumers purchase product that looks successful or will have a productive cycle: if not they elect other product.
You bring some great info and input to the forum. Welcome to the forum and look forward to your input and the projects you've been involved.