@THARGOR. Here's the link to the replacement battery I purchased :
https://www.ebay.com.au/itm/Replacem...frcectupt=true
When I ordered it, I was expecting the battery to come as on the photo only wrapped in bubble wrap or the like but it came in fact in a sealed presentation box and it looked to me like new stock - I don't know how old this stock was but the model of this battery is used in other readers apart from Kobo so I would be surprised if it is not still being produced.
I read your thread. Something weird indeed seems to be going on.
Having said this, I should tell you that the first time I fully charged the new battery, the next morning it had dropped from 100% to 85% charge like it did for you. I was a bit concerned but thereafter, it dropped only 1 or 2% each day. And on the second full charge, it didn't do like the first time and only discharged as one would expect 1 or 2 % overnight. I assume that the first initial 15% decrease was because it was only the first time the battery was charged and it was not optimized. As I said before, the info that came with the battery explains that it takes a few full charges before the battery operates at full capacity.
Also, all my books are in the Kepub format on the reader. My collection in Calibre is in epub but I use the KoboTouchExtended (3.15) plugin and I set it up so that the books are converted on the fly to Kepub when I transfer them to the reader. So all the books (over 1000) on the Glo HD are in Kepub. I prefer the Kepub format for a few reasons: the reader can display the number of pages left in chapters, and also I have a few novels that each consists of many hundred pages of text in a block without any split in chapters or even paragraph (I think) and I found that these books would take ages to open on the reader in Epub format and every page turn would take about a minute as to make the book itself essentially unreadable, however in the Kepub format, the book still take a few seconds longer than ordinary books to open but once opened, the page turns are as quick as any normal book. On the other hand, I never came across any downside to using Kepub. All the books display perfectly.
Finally, I have no problem with the USB connection. This could be the main issue in your case, I would surmise.
Personally, if I were to get a new ereader, in view of what is available from all brands right now, I would go for the Clara HD. It's seems to me to be pretty much like the Glo HD (which I love) with the added bonus of the warmer lighting, which is the only thing I would add to the Glo HD to make it perfect (
for me).
Cheers