Only a rough indicator Derek, as a charger's time tends to vary. My experience is that generally they run a touch longer than theory would predict, probably as a result of the need to slightly overrun the switch off point in order to trigger it.
That would make the range slightly longer than the value you can calculate from your part charge time, but due to the way in which battery performance declines as they empty, it's often not too accurate a predictor. There's no substitute for running out to empty to find out, but bear in mind that Li-ions prefer not to be fully discharged often if they are to last a long time.
The Sprint's range is typically very good with sensible throttle use, 25/30 miles and sometimes even more.
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