I have a Kobo that is around a year old and it's battery is discharging at an outrageous rate - even when 'asleep'.
Being out of warranty I would merrily open it up and see about replacing the wee thing.
I also have a thing that uses 4 AA batteries with a mini-USB connector which will power it.
Aside of this one problem I consider the Kobo my 2nd best reader, after the EZReader.
I will now search for a non-Alibaba source of a single H503456 1000mAh 3.7v battery.
(And BTW - Borders is blowing Kobos out at their stores for $60 - nice deal !)
Edit/addition:
A post here about the Pocket Book 360 mentions what appears to be the same battery, and it is found here:
http://www.sparkfun.com/products/339
For about $12 = shipping.
Has anyone tried this in a Kobo ?