Electric Wheelchair Charging Cost Calculator

How to Estimate Electric Wheelchair Charging Cost

This calculator helps you estimate how much it costs to charge a powered or electric wheelchair using your home electricity. By entering a few battery details and your local electricity rate, you can see:

• Energy used per full charge (in kWh)
• Cost of a full charge
• Cost per mile of use
• Estimated daily and monthly electricity cost based on your mileage

The tool is primarily designed for powered wheelchairs, but you can also use it for similar mobility devices (such as mobility scooters or power-assist wheels) as long as you know the battery voltage, capacity, and typical range.

Inputs You Need

Before you use the calculator, gather the following information:

• Battery voltage (V) – Common values for power wheelchairs are 24 V or 36 V. Check the battery label or user manual.
• Battery capacity (Ah) – The amp-hour rating (for example, 35 Ah, 50 Ah, 70 Ah). Often printed on the battery.
• Charger efficiency (%) – Accounts for energy lost as heat during charging. If you do not know it, a typical value is 80–90%. The default of 85% is a reasonable average.
• Electricity rate ($/kWh) – The price you pay per kilowatt-hour, found on your electricity bill.
• Range per charge (miles) – How far your wheelchair typically travels on a full charge under normal conditions.
• Miles traveled per day – Your typical daily driving distance in the wheelchair.

Once these values are entered, the calculator estimates your charging energy use and cost for a single charge, each mile you travel, and your daily or monthly total.

Formula Behind the Calculator

The calculator first estimates the energy stored in the battery and then adjusts for charger losses. The key steps are:

1. Compute battery energy in watt-hours:
   Wh = V × Ah
2. Convert watt-hours to kilowatt-hours:
   kWh (battery) = Wh ÷ 1000
3. Account for charger efficiency (η) to find energy drawn from the wall:

where:

• E is the energy drawn from the wall in kilowatt-hours (kWh)
• V is battery voltage (V)
• Ah is capacity in amp-hours
• η is charger efficiency as a decimal (e.g., 0.85 for 85%)

The cost of one full charge is then:

Cost per charge = E × electricity rate ($/kWh)

If you know how many miles you get from a full charge, you can estimate:

• Cost per mile: Cost per charge ÷ range per charge
• Daily cost: Cost per mile × miles per day
• Monthly cost (approximate 30-day month): Daily cost × 30

Worked Example

Suppose you have the following powered wheelchair:

• Battery voltage: 24 V
• Battery capacity: 50 Ah
• Charger efficiency: 85%
• Electricity rate: $0.15 per kWh
• Range per charge: 15 miles
• Miles traveled per day: 3 miles

1. Energy per charge

First calculate the watt-hours:

Wh = 24 × 50 = 1200 Wh

Convert to kilowatt-hours and adjust for charger efficiency:

E = (1200 ÷ 1000) ÷ 0.85 ≈ 1.41 kWh

2. Cost per charge

Cost per charge = 1.41 × 0.15 ≈ $0.21

3. Cost per mile

Cost per mile = $0.21 ÷ 15 ≈ $0.014 per mile

4. Daily and monthly cost

For 3 miles per day:

Daily cost = 0.014 × 3 ≈ $0.04 per day

Monthly cost ≈ 0.04 × 30 ≈ $1.26 per month

These numbers show that electricity cost for an electric wheelchair is typically modest, but still useful for budgeting and comparing different mobility options, especially when multiple devices are charging in the same household.

Example Comparison of Monthly Electricity Cost

The table below illustrates how monthly electricity cost can change with different daily mileage, using the example setup above (24 V, 50 Ah battery, 85% charger efficiency, $0.15/kWh, and 15 miles per charge). The underlying cost per mile is about $0.014.

Use this as a rough guide only. Your own values will differ depending on your chair, route, and electricity rate. The calculator will generate numbers tailored to your inputs.

Interpreting Your Results

Once you run the calculator, focus on the following outputs:

• Energy per charge (kWh) – Indicates how big a “load” your wheelchair places on your home electricity for one full charge.
• Cost per charge – Helpful for understanding what each full battery top-up costs.
• Cost per mile – Useful for comparing different wheelchairs, scooters, or even car trips on a per-mile basis.
• Daily and monthly costs – Helps with budgeting, especially if you are on a fixed income or if multiple mobility devices share the same household electricity.

If the daily or monthly cost seems higher than expected, you can explore options such as more efficient chargers, off-peak electricity tariffs, or adjusting how often you fully charge the batteries (always considering manufacturer guidance to protect battery health).

Assumptions and Limitations

This calculator provides estimates, not exact bills. Several real-world factors can cause your actual electricity use and cost to differ from the results:

• Battery health and age – Older or damaged batteries may waste more energy as heat and may not hold their full rated capacity.
• Terrain and driving style – Hills, rough surfaces, frequent starts and stops, and carrying extra weight reduce range per charge, increasing cost per mile.
• Temperature – Very hot or cold weather can change both battery efficiency and driving range.
• Manufacturer ratings – The rated capacity (Ah) and range are often measured under ideal test conditions and may not reflect everyday use.
• Charger differences – Actual charger efficiency can vary outside the assumed percentage, especially for very old or very cheap chargers.

Because of these factors, treat the results as a planning tool rather than a guarantee. For medical or financial decisions, combine these estimates with your actual electricity bills over time.

Using This Tool for Other Mobility Devices

Although this page focuses on powered wheelchairs, you can adapt the same method for:

• Mobility scooters
• Power-assist wheels for manual chairs
• Other small battery-powered mobility aids

For each device, simply enter its own battery voltage, amp-hour capacity, range per charge, and your electricity rate. The resulting cost per charge and per mile can help you compare running costs between different options.

Practical Ways to Use the Results

Wheelchair users, caregivers, and household budget planners can use the calculator outputs to:

• Estimate how much of the electricity bill is due to charging one or more mobility devices.
• Compare models before purchase by looking at cost per mile and energy per charge.
• Plan charging schedules to take advantage of off-peak electricity rates where available.
• Discuss energy usage with landlords, roommates, or care facilities when sharing utilities.

By making the ongoing operating cost visible, this tool supports more informed decisions about mobility, independence, and home energy budgeting.