Comparison of Outdoor Power Supply Charging Efficiency: Which is the Most Cost-Effective—Mains Power, Car Charging, or Solar Charging?
Ⅰ. Core Parameter Comparison of Three Charging Methods: Intuitive Differences in Speed and Cost
Mains Power Charging: Most mainstream outdoor power supplies support mains charging power ranging from 60W to 2000W, with higher power leading to faster charging. Tests show that a 1000Wh outdoor power supply takes 1.8-2 hours to fully charge from 0% to 100% with a 600W mains charger, and 5-5.5 hours with a 200W mains charger. In terms of cost, based on a civilian electricity price of 0.56 yuan per kWh, fully charging a 1000Wh outdoor power supply only costs 0.56 yuan, making it the lowest unit electricity cost among the three methods.
Car Charging: Divided into cigarette lighter sockets (output power 12V/24V, approximately 60W-120W) and on-board fast charging interfaces (supporting 12V/24V, power up to 150W-300W). Tests indicate that a 1000Wh outdoor power supply takes 8-9 hours to fully charge with a 120W cigarette lighter car charger, and 3.5-4 hours with a 300W on-board fast charging interface. Regarding cost, car charging relies on automotive fuel. Based on a fuel consumption of 8L per 100 kilometers and a fuel price of 8 yuan per liter, the cost per kWh is approximately 2.5 yuan, higher than mains power charging.
Solar Charging: Charging efficiency is affected by the power and conversion rate of solar panels. Common outdoor solar panels have a power of 100W-400W and a conversion rate of 18%-23%. Tests show that a 200W solar panel can fully charge a 1000Wh outdoor power supply in 6-7 hours under standard light conditions (1000W/㎡); if the light intensity drops to 300W/㎡ (cloudy days), it takes 18-20 hours. In terms of cost, solar panels require a high one-time investment (a 200W solar panel costs about 800 yuan), but there are no additional costs for subsequent use, making them more cost-effective for long-term use.
Ⅱ. Analysis of Factors Affecting Solar Charging Conversion Rate
Light Intensity: Light intensity directly determines the power generation of solar panels. The standard test condition is 1000W/㎡. In actual outdoor environments, the intensity can reach 800-1000W/㎡ during midday strong light, and only 200-300W/㎡ in the early morning and evening. Tests show that for every 100W/㎡ decrease in light intensity, the power generation of solar panels decreases by approximately 10%-12%, and the charging time is correspondingly extended by 15%-20%.
Panel Angle: The conversion rate is highest when the solar panel is perpendicular to the sun’s rays. In the Northern Hemisphere, the optimal installation angle is approximately equal to the local latitude. A deviation of 10° from the optimal angle reduces the conversion rate by 5%-8%; a deviation of 20° reduces it by 12%-15%. For example, in Beijing (39°N latitude), setting the solar panel angle to 39° results in 12% more daily power generation than setting it to 29°.
Weather Conditions: The conversion rate is highest on sunny, cloudless days, dropping to 30%-40% of that on sunny days on cloudy days, and only 10%-15% on rainy days. Tests show that the same 200W solar panel can generate 1.2-1.4kWh of electricity per day on sunny days, only 0.4-0.5kWh on cloudy days, and less than 0.2kWh on rainy days.
III. Frequently Asked Questions: Addressing Outdoor Charging Concerns
Can charging be done on cloudy days? Yes, but efficiency is significantly reduced. Tests show that on cloudy days (light intensity 300W/㎡), a 100W solar panel takes 10-12 hours to charge a 500Wh outdoor power supply from 0% to 50%, which can only meet the power supply needs of low-power devices such as mobile phones and small camping lights, and cannot quickly replenish the power of large-capacity outdoor power supplies.
Will car charging damage the battery? It will not damage the battery when used standardizedly. Two points need attention: first, choose a car charger matching the car battery voltage (12V charger for 12V cars, 24V charger for 24V cars); second, charge when the car is started to avoid power loss. Tests show that charging an outdoor power supply with a 120W car charger while the car is running for 2 hours only reduces the battery voltage by 0.3V, which is within the safe range; if charging with the car turned off, the battery voltage drops by 1.5V after 2 hours, which may cause the car to fail to start.
Compatibility of solar panels with different powers: Small-capacity outdoor power supplies (below 500Wh) are compatible with 100W-150W solar panels and can be fully charged in 6-8 hours; medium-capacity outdoor power supplies (1000Wh-2000Wh) are compatible with 200W-300W solar panels, taking 5-7 hours to fully charge; large-capacity outdoor power supplies (above 3000Wh) require solar panels of 400W or more, or multiple solar panels connected in parallel, to ensure charging efficiency.
- Charging Time Estimation Formula and Outdoor Power Consumption Endurance Planning Table
Charging Time Estimation Formula: Charging time (hours) = Outdoor power supply capacity (Wh) ÷ Actual power of charging method (W) ÷ Charging efficiency (0.9 for mains power/car charging, 0.8 for solar charging). For example, a 1500Wh outdoor power supply charged with a 300W on-board fast charger: time = 1500 ÷ 300 ÷ 0.9 ≈ 5.5 hours; charged with a 200W solar panel under 500W/㎡ light conditions (actual power = 200 × 500 ÷ 1000 = 100W): time = 1500 ÷ 100 ÷ 0.8 ≈ 18.75 hours.
Outdoor Power Consumption Endurance Planning Table (taking a 1000Wh outdoor power supply as an example):
Application Scenario Core Electrical Equipment Device Power (W) Daily Usage Duration (h) Daily Power Consumption (Wh) Supportable Days
Camping 100W projector + 50W camping light 150 4 600 1.5
RV 80W refrigerator + 120W parking air conditioner 200 8 1600 0.6 (midway charging required)
Emergency Rescue 200W walkie-talkie + 100W medical equipment 300 6 1800 0.5 (fast charging required)
Ⅳ. Details and Standards: Ensuring Charging Safety and Efficiency
Material and Craftsmanship: High-quality outdoor power supply charging interfaces adopt gold-plated craftsmanship to reduce contact resistance and charging heat generation; the surface of solar panels is covered with impact-resistant tempered glass, which can withstand hail and sandstorms, with a service life of more than 10 years.
Industry Standards: The charging performance of outdoor power supplies must comply with “Technical Requirements for Portable Lithium-Ion Battery Energy Storage Power Supplies” (GB/T 40278-2021), which clearly stipulates that the mains charging efficiency shall not be less than 85%, and the solar charging efficiency shall not be less than 75%; car chargers must comply with “Technical Conditions for Low-Voltage Wire Harnesses for Automobiles” (QC/T 29106-2014) to avoid damage to the car circuit during charging.
Safety Protection: Regular outdoor power supplies are equipped with overvoltage protection, overcurrent protection, short-circuit protection, and overtemperature protection functions. When the charging voltage or current is abnormal, the circuit will be automatically cut off; some products are also equipped with battery balancing technology, which can extend the battery cycle life to 800-1000 times.
