May be charged. But it's very slow, the charging current is around 100mA. Generally, 20 W corresponds to the data under 1000 W/m2 irradiance. On cloudy days, the irradiance is only 300-400W. In addition, the efficiency of 20W solar panels is low (thin film efficiency is 5%-6%, crystalline silicon) . The efficiency is 11%), so the electricity production is even lower.
How many kilowatt hours of electricity does a solar water heater need per day on rainy days?
It is basically useless on rainy days. Solar energy is used to charge the battery. there is sunshine and is used at night or on rainy days. This is the electricity in the battery.
However, current photovoltaic power generation systems are complementary to mains power, and solar power is used first if there are not enough solar points or sIf they are exhausted, energy will automatically be drawn from the mains. electrical network.
My opinion: 1. Assuming that the general power of an electric water heater is 1.5KW, heating requires 1.5 kilowatt hours per hour. If your water heater is around 50L, calculated in winter, the heating is the highest. The temperature (usually 75 degrees plus or minus 5 degrees) requires about two hours of heating time, which is equivalent to 3 degrees of electricity. Additionally, if your water heater is not electronic...