Is it possible the battery was was warm when you went to charge? Need to let them cool a bit before charging.I had a funny issue with mine this past weekend. I flew the battery down pretty low, plugged it into my battery bank and an outlet. When I would come back to check on it, it would only have 1 blinking light (not the first light either what would be #4 or the fully charged light was blinking). This went on for well over an hour on both charging devices. I un-plugged the battery from the Spark and plugged it back in, after that it seemed to charge like it normally would.. No big deal, just thought I would share my issue.
Yes it was warm but not hot, I think it got even warmer sitting there on the charger without it doing anything (which makes sense).Is it possible the battery was was warm when you went to charge? Need to let them cool a bit before charging.
I'm using all top of the line 2.1 - 5 amp QC chargers. An in-line meter shows that the actual draw is just shy of 2 amps.It all depends on the Wattage of the charger behind the usb port, not the usb port itself.