Well, let's just go off of the three that we know of then. You, myself, and the user that said they are getting 10 hours. That is a 66.66% defect rate. That would be the kind of defect rate of on a product to have these same types of repeatable problems through-out the world I suppose. And to be clear, the question I asked was how many of the reviewers were paid reviewers. I'm didn't necessarily outright call these folks liars, but let's be real, we all know how reviews are these days because of such paid reviewers. EvilOne hit it on the mark with the very first sentence they posted. I do believe the way I run mine definitely contributes to its battery usage, though...not a 6 hour difference, however. As far as warranty goes though, I have unfortunately surpassed the warranty time thst they offer some time back. And then there are the logistics and time that it would likely take to even do so....as you pointed out....if I was still within warranty. How many weeks....or months...would that take? But I am definitely with you, I think mine is defective, just like yours. Maybe 66.66% of them are defective, who knows, lol. I'll use it until it dies, but I do love the sound from it.Well as for the community on here only 2 people commented when I asked about the UP5's battery life using balanced port. One of them mentioned they are getting 10 hours worth of back up and you said you're getting maximum 4 and even doubted the other guy.
I've owned both Shanling UP4 and Fiio BTR 5 and used to get minimum 6 hours worth of battery back up on a single charge using their balanced port. So I would be really surprised that somehow UP5 went backwards in terms of battery life. On the other hand Shanling themselves have claimed 11 hours battery back up on the UP5 using the balanced port, while I do realize real life usage will vary but there is a huge difference between claimed 11 hours and actually getting 3 hours only. The Shanling sponsor account themselves asked me to claim warranty when I reported this issue here.
So in my humble opinion, rather than every single reviewer lying about the battery life they are getting on their UP5, it seems to me you've gotten a faulty device just like me and convinced yourself that nothing is wrong. I would reconsider my point of view if more forum members came forward and reported they are getting the same 3 to 4 hours worth of battery life using the balanced port, but that hasn't happened yet.