I think, there is a dirrerence in the chargers quality too. I had a Chuwi vi10 32GB. A lot longer to charge. With my Lenovo p780 charger too, and from pc usb 3 port too.
Now i have a Chuwi vi10 pro 64GB. With both charger i can charge normally when i use Windows 10/droid. (avarage usage, web browsing+winamp+office) The old chuwi rather exhausted than charged.
In quality there are differencies. For example in 32gb version was noname emmc, 40/40 speed,now in pro version Samsung ~160/80 MB/s. And no buzzing with 3.5 jack.