Why EV fast charging slows down after 80%

The charger showed a good rate when you plugged in. Half an hour later, the battery is above 80%, the power has fallen and everyone in the car is ready to leave. Moving to a bigger charger may not shorten the wait. The car can ask for less power as its battery fills.

Before another cup of tea turns into another hour, check the next leg. You may already have enough energy to reach a confirmed charging stop with a reserve. Or you may need the extra charge because the next usable plug is much farther away. Either decision needs a route plan; 80% alone does not settle it.

Read the charging window in the brochure

The Punch EV manual hosted by Sipradi gives its DC estimate for a 10–80% window under stated test conditions. Read that window alongside any advertised charging time.

A published window is part of the claim. A 0–80% figure, a 10–80% figure and a complete 0–100% figure describe different energy additions. Keep the battery size, starting percentage and ending percentage beside the time when comparing cars.

The charger rating also differs from the rate accepted by the car. The usable power is limited by the vehicle, equipment and supply under the actual conditions. Temperature and shared station power can change it. An 80 kW car connected to a 120 kW station does not thereby become a 120 kW car.

Maximum power is not average power

Consider a hypothetical 50 kWh usable battery. Going from 10% to 80% adds about 35 kWh. At a constant 50 kW delivered to storage with no losses, that would take 42 minutes. A lower average rate or losses lengthen the session.

If 35 kWh reaches the battery over 56 minutes, the average addition is 37.5 kW. The peak could have been higher for part of the session. Peak and average are both legitimate measures, but they answer different questions.

For the next 10 kWh, an illustrative average of 15 kW would take 40 minutes. At 10 kW it would take an hour. These are arithmetic scenarios, not a charging curve for the Punch or any other named model. The final fifth can take much longer than a driver expects after watching the earlier, faster part of the session.

An electricity unit is a kilowatt-hour (kWh). The charger screen's kilowatts (kW) describe the rate at that moment. A falling kW figure means each remaining unit will take longer.

A good charging comparison records the full power curve or at least the measured energy and window. A single photograph showing a high peak tells you little about the wait until departure.

Calculate the next leg before unplugging

Suppose the car has 50 kWh usable and you plan to retain 20% on arrival. Leaving at 80% makes 30 kWh available. A 150 km leg at 18 kWh per 100 km needs 27 kWh, leaving 3 kWh within that planned allowance for additional use.

If a diversion turns the leg into 180 km, the assumed requirement becomes 32.4 kWh. The same departure charge no longer fits. Charging longer, adding another verified stop or delaying the journey becomes a sensible change.

These percentages are example choices, not a universal safe reserve. A climb, rain, a full car or a charger failure can alter the requirement. Use your own recent consumption and current route information.

Check the alternative before leaving. The CG Motors directory provides connector and location information; the operator must confirm access and operation. A listed plug beyond a closed road is not useful reserve protection.

When a slower full charge makes sense

A long stretch with no confirmed alternative can justify more charge. A destination without charging can also change the arrival target. The last units are slow, but their value comes from the journey they enable.

Battery-care guidance is a separate question. The same Punch manual's battery-care section calls for full AC charging as part of its care routine. That instruction belongs to the model and manual revision. A useful departure percentage at a roadside DC charger should not become a daily charging rule for every EV.

Follow the exact model's daily and periodic charging instructions. A route-planning target should not silently become a warranty or storage recommendation.

Low power early in the session deserves another enquiry

If the battery is low and charging is unexpectedly slow, ask whether the station shares power, is derated or has a supply problem. Record the arrival charge, displayed power, weather and whether another car is connected. The operator may be able to explain the equipment state.

Temperature can also affect the vehicle's limit. A demanding climb immediately before charging can create different conditions from a gentle drive. Some cars have preconditioning features; availability and operation need confirmation for the Nepal variant.

Repeated failure at several known working chargers warrants a service enquiry. Do not diagnose a defective battery from one slow stop, and do not force a damaged connector or use an unapproved adapter.

Leave the bay when the job is done

Once the car has enough energy for the planned leg and reserve, complete the session and move according to the operator's rules. Check the receipt for energy, fees and any parking charge.

At a busy stop, an avoidable final top-up can delay someone who needs the plug to reach home. A driver with a genuinely long next leg may need it, though. Clear queue rules and a realistic departure target work better than arguments over one percentage.

Before unplugging, check your departure charge, the next stop's connector and its access arrangements. Our charging-station map helps with locations; call the operator to confirm that the charger works for your car. If you can reach that stop with a sensible reserve, you can leave without waiting for the display to reach 100%.