Power — kW
Kilowatts describe the rate of energy transfer. A charger delivering 7 kW for one hour supplies 7 kWh before charging losses and vehicle overheads.
Understand the plug. Plan the stop.
Charging speed, without the guesswork.
A bigger charger rating can mean a faster charge, but only if your car can accept that power. Your vehicle’s limits, battery temperature and charge level all affect the result.
Reviewed 18 October 2026. General guidance; follow the handbook and charging recommendations for your exact battery, model year and software.
Worked example · Zeekr 7X
How much does a granny charger add?
A portable charger delivering 2 kW (assumed constant input power) could add about 9 km of driving range per hour, or 27 km over a three-hour charging window, under the assumptions below. That can cover a modest daily commute without a faster home charger.
Example assumptions: 90% of socket energy reaches the battery (10% losses/overheads); driving consumption is 20 kWh/100 km; charging remains at the stated power and the battery has room below its charge target. These are adjustable estimates, not measured Zeekr charging results or a claimed real-world consumption figure.
| What you gain | 1 hour | 3-hour free window | 3 hours free + 3 hours surplus solar |
|---|---|---|---|
| Energy at the socket | 2 kWh | 6 kWh | 12 kWh |
| Energy stored in the car (estimated) | 1.8 kWh | 5.4 kWh | 10.8 kWh |
| Added driving range at 20 kWh/100 km | About 9 km | About 27 km | About 54 km |
| 75 kWh 7X RWD: battery gain | About +2.4 percentage points | About +7.2 percentage points | About +14.4 percentage points |
| 100 kWh 7X Long Range RWD / Performance AWD: battery gain | About +1.8 percentage points | About +5.4 percentage points | About +10.8 percentage points |
“+5.4 percentage points” means approximately 50% → 55.4%, not a 5.4% increase in the existing reading. Percentage estimates use Zeekr’s advertised 75/100 kWh capacities as a proxy; confirmed usable capacity and the displayed battery gauge may differ. Solar hours are an assumed extra three hours at full charging power, not a daily forecast.
An 8 A setting at 230 V is about 1.84 kW: under the same assumptions it adds about 8 km per hour or 25 km in three hours. Check what your portable charger actually delivers. Very low-power AC charging can have proportionally larger losses, especially with battery heating/cooling active.
At 18–22 kWh/100 km instead of the example’s 20, the 2 kW three-hour window works out to about 25–30 km. Your road speed, weather, load and measured consumption decide the real result.
Zeekr Australia: battery variants ↗ · Australian 7X brochure ↗ · Zeekr 7X model guide →
Try your own charging window
What GloBird’s three free hours mean
The example uses the three free hours on GloBird ZEROHERO. Its published standard-circuit free-use window is 12–3 pm for customers joining from 1 July 2026; earlier customers may have 11 am–2 pm. Confirm your Welcome Pack and current fact sheet, eligibility, local-time rules and circuit coverage.
The current ZEROCHARGE fair-use limit is 50 kWh per day based on a standard 28-day billing cycle. This is a household-wide allowance, not an extra allowance for the car: home-battery charging and other loads also count. Controlled-load/dedicated circuits are excluded from the free rate. Daily supply charges and other plan conditions still apply.
The 2 kW example uses 6 kWh at the socket during the three hours. “Free” describes the eligible grid-energy charge in that window, not free equipment or a guaranteed zero household bill.
Plan terms checked 18 October 2026. Official ZEROHERO terms and window ↗ · GloBird quote — referral code W01VJR ↗
Add surplus solar before or after the free window
Home Assistant can coordinate this if you have compatible energy monitoring and a supported way to control the car or charging equipment. Do not assume a Zeekr API or a particular portable charger supports remote control or current adjustment.
- Free-window mode: when the confirmed tariff window is active, the car is plugged in and below its target, permit charging at the safely configured rate. Keep total household demand within supply limits and monitor the shared free-use allowance.
- Outside-window mode: permit additional charging only while there is genuine surplus solar after household loads and your chosen home-battery reserve/charging priority. Surplus can be available before noon as well as after the free window.
- For a fixed 2 kW portable charger: an illustrative start condition is export above about 2.3 kW for five minutes while the EV is off. Once charging starts, monitor net import/export and home-battery discharge—do not keep requiring 2.3 kW of export after the car has consumed the surplus.
- Clouds and household loads: pause if sustained grid import or unwanted home-battery discharge occurs outside the free window. Use sensible start/stop delays and minimum run/off times to avoid frequent switching. Thresholds and delays need tuning to your meter and equipment.
- Protect your reserve: a home battery can hide a solar shortfall by powering the car. Check battery power as well as grid power so you do not unintentionally empty the battery needed for the evening or conflict with VPP control.
- Fail safely: stop or revert to a known safe schedule if tariff data or power sensors are stale/unavailable. Include a charge target, departure-time override, manual stop and notifications. Use one automation controller per device.
A fixed-rate granny charger cannot continuously follow small changes in solar output. Adjustable-current charging needs an appropriately supported EV/charger integration and must respect its minimum current. Use manufacturer-supported controls; a Wi-Fi plug is suitable only if its use is permitted and the device/circuit have been assessed for sustained EV charging.
The automation sequence is a design example, not a tested configuration for a Zeekr. Home Assistant energy monitoring ↗ · Example of supported solar-divert equipment: OpenEVSE ↗ · Create your own energy automation prompt →
kW is speed. kWh is energy.
Energy — kWh
Kilowatt-hours describe an amount of energy. A 60 kWh usable battery needs approximately 6 kWh stored to increase from 50% to 60%.
Time — hours
Charging time ≈ energy added ÷ average charging power. Use the session’s average power, not its advertised peak. Losses and power used for heating or cooling increase the energy drawn from the charger.
The main types of charger
| Type | Typical power | Where it fits | What can limit it? |
|---|---|---|---|
| Portable AC charger Often called a granny charger | About 1.4–2.4 kW on a suitable standard 10 A outlet | Slow top-ups while parked overnight or through the day. | Portable unit’s current setting, outlet/circuit suitability and vehicle limits. |
| AC wallbox or destination charger | Around 7 kW single-phase; 11 or 22 kW three-phase equipment | Home, work, shopping and accommodation stays. | The car’s onboard AC charger, electrical supply, cable and any shared-load controls. |
| DC charger | Lower-power DC around 25–50 kW; fast/ultra-rapid units commonly 100–350 kW or more | Shorter public charging stops and longer journeys. | Vehicle DC acceptance, battery condition, charger voltage/current capability and site power sharing. |
AC equipment supplies alternating current; the car’s onboard charger converts it to DC for the battery. A DC charger performs that conversion outside the car, so it bypasses the onboard AC charger. A car can therefore have very different AC and DC limits.
Type 2 is common for Australian AC charging and CCS2 for DC. Some older vehicles use Type 1 AC or CHAdeMO DC. Check the exact vehicle and station; some plug-in hybrids support AC charging only. “Level 1/2/3” and “fast/rapid” labels vary—look for the actual kW, AC/DC type and connector.
References: Australian Government: charging equipment ↗ · EVSE Australia: AC and DC ↗
Your car can be the bottleneck
The rate is constrained by the car, battery management system, charging equipment, connection and available site power. A cold or hot battery, another vehicle sharing a charger’s capacity, or a voltage/current mismatch can reduce it further. A published peak is a maximum under suitable conditions, not a rate maintained from empty to full.
Why the last 10% can take so long
The vehicle controls power as the battery fills. DC charging often runs faster at lower and middle charge levels, then tapers as the battery approaches full. Above about 80%, and particularly through the final 10%, it can become much slower. The exact curve varies by battery and conditions; there is no universal 80% cliff.
Think of it as filling the final part carefully: the battery management system reduces current to keep cells within their operating limits. Thermal management and cell balancing may also add time near full. A “10–80%” charging time cannot be scaled directly into a “10–100%” time.
Fast charging tapers. Granny charging stays steadier.
Illustrative shapes only — not measured vehicle data and not drawn to a power ratio.
DC fast chargerGranny charger (portable AC)
On a road trip, two useful charging stops can be quicker than waiting for 100% at one stop. Charge enough to reach the next reliable stop with a sensible reserve. If the next leg needs more energy, charge higher—range and a workable backup matter more than an arbitrary target.
Australian Government: charging slows as the battery fills ↗ · Ford: DC charging taper example (vehicle-specific) ↗
Optimise charging for your battery and your day
Normal daily use
If your car recommends an everyday limit around 80%, use it when that covers your needs. Schedule charging for a suitable tariff or solar window and avoid unnecessary time sitting near empty or full.
80% is not a rule for every EV. Some LFP vehicles call for regular 100% charges. PHEVs can also have different guidance and usable battery buffers. Use the recommendation displayed by your car and its handbook.
Before a big trip
Where the handbook allows, raise the target to 100% when you need the additional range. Aim to finish close to departure instead of leaving the car fully charged for days, especially in heat. Restore the normal target afterwards if applicable.
Plan with realistic consumption, temperature, towing/load and charger availability. Set the destination in the car’s navigation if the vehicle uses it to precondition the battery for DC charging.
At a public DC charger
Compare the car’s supported charge rate with the station, monitor the actual rate and leave once you have enough energy for the next leg. Check time-based/idle fees and avoid holding a busy bay for the slow final few per cent unless you need that energy.
Follow the vehicle’s preconditioning instructions. Do not assume every model preconditions automatically.
Tesla Model 3 handbook: follow the vehicle’s recommended limit; avoid prolonged extremes ↗ (regional example—confirm your Australian vehicle handbook).
Battery calibration: follow your model’s schedule
Calibration helps the battery management system estimate the displayed state of charge and range. A full charge can also give the system an opportunity to balance cells. It does not restore lost battery capacity.
Do not apply a blanket “100% every three months” routine. Some manufacturers call for a full charge much more often. For example, the 2025 BYD Atto 1 handbook recommends a full charge at least weekly, and separately describes a low-to-full charge every three to six months. That is model-specific guidance, not an instruction for all EVs.
Check your exact handbook for the charge level, interval, AC/DC requirements and whether a low-to-full cycle is actually specified. Do not deliberately run a battery low for calibration unless the manufacturer instructs it. Keep a safe margin to reach a charger and seek manufacturer support if charge readings behave abnormally.
BYD Atto 1 Australian handbook (2025): battery charging and maintenance ↗ · Find your manufacturer’s owner resources →
Ask about your own car
Check your EV arrangements with AI
Explore charging, trips, running costs, maintenance and practical ownership questions. Enter what you know, choose a topic and copy the prompt into your preferred AI tool. Leave unknown details blank—the prompt asks the AI to clarify them. Do not include your VIN, registration or account numbers. Inputs are not saved or submitted.
Choose equipment for the job
A portable charger can cover modest daily kilometres if you have enough parked time and a suitable outlet. Have the circuit and installation assessed by a licensed electrician; follow the equipment instructions. A faster wallbox is useful when your daily energy needs and available charging window justify it.
Plan the stop and prepare the account.
Keep the right apps and tested RFID cards ready before travelling.