Is the power supply unit available for purchase separately? Or any other alternative? Is it possible that the Zenfone 7 Pro can only be charged with the supplied power adapter? Because when I use another one, it doesn't charge... when I try to charge it on the computer, it shows that it's charging, but after a few hours, I have less battery than before. So far, the only way I've been able to charge it without the original power supply was on the Playstation, but even there it was very slow (better than not at all). So I always have to take it with me on my trips, which increases the likelihood of losing it and then I can't charge it at all.