Why "20 to 80 percent" keeps appearing
Battery researchers are unanimous on one habit: lithium packs age slowest in the middle of their charge range. Sitting at 100 percent for hours, or draining to near zero, both stress the cells. That is why most manufacturers quietly recommend daily charging between roughly 20 and 80 percent, saving full charges for days when you genuinely need the range. Our calculator defaults to exactly that window — not because 80 percent is a magic number, but because it reflects how the battery wants to be treated.
The "charging losses" field is the one people skip and then wonder why their bill disagrees with the app. Pushing energy through a charger and into a battery is not 100 percent efficient: the charger warms up, the battery management system spends some power itself, and cooling fans may run. Across home AC chargers the loss lands between 8 and 12 percent; fast DC charging loses a little more. If you pay for 5 units but only 4.5 arrive in the battery, your real per-km cost is 10 percent above the naive figure — which is exactly what this field corrects for.
Home versus public: the price gap that decides everything
The same electron costs wildly different money depending on the socket. Home tariffs across Indian states mostly fall between ₹6 and ₹10 per unit. Public charging networks typically bill ₹18–25 per unit for the same energy, sometimes with a session fee on top, because you are paying for the station, the land and the uptime — not just electricity. That is a 2–3x difference, and it means the same electric scooter can cost ₹0.25 per km when charged overnight at home and ₹0.70 per km when lived on public stations.
Neither price is a rip-off. Public fast charging buys you 30–60 saved hours and highway viability; home charging buys you patience. The correct strategy for most owners is boring and effective: charge at home whenever possible, treat public chargers as the exception for trips, and let this calculator tell you what each habit costs per month.
How long charging really takes
Time is energy divided by power, but ratings mislead. A "3.3 kW" home wall box usually delivers closer to 2.8–3 kW after losses; a 7.4 kW unit needs the right wiring and a car that accepts that rate. DC fast chargers advertise their peak, not their average — a "50 kW" station may average 35 kW across a session as the battery tapers above 80 percent. The calculator uses the honest number you enter; when a station's display shows average session power, believe that over the sticker.