Article Source: Beyond the Snowline, https://mp.weixin.qq.com/s/HDwz-dicK8Y9-YYfcynzWg
It depends, if you are a single person and use more than 4 power banks during the trip, it is only cost-effective to bring solar panels. If it is a team of 2-3 people, and each person brings his or her own power bank to share a solar panel, then the weight is much more cost-effective than each person bringing their own power bank. Or if your trips takes more than 5 days and the weather is full of sunshine, then a solar panel is highly recommended.
Introduction
When it comes to mountaineering, the decision to bring a solar panel is a crucial one. The key factors include the weight compared to carrying additional power banks, as well as the charging capacity. In this article, we’ll analyze whether bringing a solar panel is worth it, considering factors such as weight, charging speed, and efficiency.
Choosing a Solar Panel
Selecting a solar panel involves considering a few essential parameters:
1. Wattage
Choose a solar panel with at least 18 watts, as higher capacities are recommended for efficiently charging devices with larger battery capacities.
2. Solar Conversion Efficiency
Opt for panels with a conversion rate of 14% to 23%, with higher values indicating better performance. Outdoor solar panels typically have conversion rates exceeding 20%. Solar panel with too low conversion rates require a larger area to achieve the same wattage, resulting in higher weight and are not suitable for outdoor use.
3. Panel Type
Prefer single-crystal silicon panels over thin-film options for better durability and efficiency.
4. Built-in Battery
Avoid panels with built-in batteries, we suggest, as the built-in battery is not usually used, and you will definitely bring a power bank with you when you decided to take a built-in battery solar panel, which adds extra weight to the extra power bank, and the working temperature of the solar panel may be very high, which is also considered to be unsafe to use a power bank together.
The above is the basic knowledge for purchasing solar panels. Of course, there are many details, such as how many sockets there are, whether the circuit is anti-overload, whether it supports fast charging, etc…
Charging Time Calculation
1. Wh
To estimate how long a solar panel takes to charge a device, we convert the device’s battery capacity from milliampere-hours (mAh) to watt-hours (Wh) using the formula: Wh = mAh / 1000 * Voltage (V).
How many watt-hours does a mobile phone or power bank consume? The voltage of mobile phone batteries and power banks is generally 3.7 volts.
For instance, a 3300mAh smartphone battery translates to approximately 12.2 Wh (3300/1000*3.7=12.2Wh); and a 10000mAh power bank translates to approximately 37 Wh (10000/1000*3.7=37Wh)
2. Charging Duration
The wattage of solar power generation panels cannot be fully utilized. It will fluctuate greatly due to time, temperature, sunlight angle, etc. Generally, it can only produce 10% to 30% of the power, unless it is when the sunshine is strong at noon when it can reach 60%~80%.
Therefore, if the actual power of a 21-watt solar panel is 20% (i.e. 4.2 watts), it will take about 3 to 4 hours to charge a mobile phone (12.2 watt-hours/4.2 watts = 2.9 hours).
If the estimate rate is more optimistic and the actual power is 30% (i.e. 6.2 watts), then it will take about 2-3 hours to charge a mobile phone (12.2 watt-hours/6.2 watts = 1.9 hours).
In summary, a 21-watt solar panel, assuming it is used for 5 hours a day (2 hours after getting up at the campsite in the morning, 3 hours at the campsite in the afternoon, and not used during the trip), can provide approximately 10.5 to 31.5 watt-hours of electricity (actual power 10% ~30%), it can basically fill a mobile phone, or even a mobile phone plus a power bank.
It seems that the effect of solar panels is okay, but are they cost-effective in terms of weight?
A 10,000 mAh power bank is about 240 grams (average about 8.9 grams/watt hour), while a 21-watt solar panel weighs about 630 grams (average about 30 grams/watt), plus you must bring at least one power bank when you take solar panels , totaling 870 grams.
In summary, if you are a single person and use more than 4 power banks during the trip, it is only cost-effective to bring solar panels. If it is a team of 2-3 people, and each person brings his or her own power bank to share a solar panel, then the weight is much more cost-effective than each person bringing their own power bank.
But, the trace length also needs to be considered. Generally speaking, a mobile phone plus a power bank can be used for 2-3 days when you turn on airplane mode outdoors and only use the mobile phone to take photos, record videos and view navigation maps. Currently, the most popular 23W solar power battery can weigh about 300g, which is almost equal to the weight of an ordinary 10,000 mAh power bank. In other words, if you take a route that lasts for more than 5 days and has sufficient sunshine, it is more cost-effective to bring one solar panel than two or more power banks in terms of weight calculation.
Cang Lang Tao
Conclusion
As more and more electrical equipment are used, the anxiety of charging when mountaineering is very obvious. If you want to use electricity more freely, a monocrystalline silicon solar charging panel with a conversion rate of over 20% over 18 watts is a good choice, especially for single-unit In scenarios where a person uses more than 40,000 mAh or a team of 2-3 people, solar power panels can not only provide power but also save weight.
In addition, the power bank can only carry a maximum of 20,000 milliamp hours (mAh). If it is more, it will not be able to get on the plane or train. Solar charging panels do not have this limitation, which is another reason to bring solar panels.
