I have successfully introduced a USB charger to my 10" inch Kogan Agora Android tablet. The tablet comes with only a 240V wall outlet charger. Obviously I wanted a USB charger as well.
I have found a USB charger and can confirm that it works just as you might expect.
My tablet was purchased direct from Kogan on 5 April 2012. I understand Kogan tend to release variants to their Android tablets over time. So individual models may vary depending on purchase date.
USB-A 5v to→ DC plug 1.35mm /3.5mm power adapter cable lead 100cm (1m).
Any USB to DC should work, just make sure the DC connection is 1.35mm/3.5mm. This seems to be the non-standard format so slightly harder to find.
http://www.ebay.com.au/itm/250993939851? ssPageName=STRK: MEWNX:IT&_trksid=p3984.m1497.l2649
This USB charger works fine. Much more convenient to now be able to charge the tablet from a computer, car, or any USB port.
