To avoid buying solar charging boards with false power ratings, you can refer to the following suggestions:

1. Understand the size and power calculation method of solar charging boards. In general, if it is not marked as monocrystalline, it is calculated as polycrystalline. If you know the size of the solar panel, you can calculate the power of the solar panel according to the following formula: length (m) × width (m) × watts per square meter (W/m2) = total power (W).

2. Understand the service life and attenuation of solar panels. The service life of solar panels is determined by the material. Silicon solar panels generally have a service life of 15-25 years. However, with the influence of the environment, the material of solar panels will age over time. Generally, after 20 years of use, the power will decrease by 30%, and after 25 years of use, it will decrease by 70%.

3. Understand the problem of false rated power. Sometimes merchants will falsely mark rated power. In this case, you can refer to the formula mentioned in point 1 to calculate whether the actual power of the solar panel meets the nominal value.