When I first got the OPO and on the first charge, I noticed that phone is taking really long time to a full charge. I switched the charger after few days of usage and it seems to charge a really quick. I went back to the original charger that was slow at the beginning. It is now as quick as anything else. As of now, the OPO is charging as normal as any phone I have had. I am little puzzled. I figured, it must be a first full charge thing.