Is off-grid solar cheaper?

The off-grid solar system designed by a professional company does not require any cost for a certain period of time instead of cheaper. After calculating the total power of the load used in your house, according to the local sun exposure, a professional EPC company will calculate a reasonable configuration, such as how many watts of solar panels and MPPT solar charge controller, how many watts of the inverter, how many Ah of the battery. Even in the rainy season, there is no need to worry about the insufficent electricity.

Let's design a simple off-grid solar system of a tiny house. The list of the equipments in you house is as follows:

1. Led lights 50W
2. Induction hobs 1800W
3. Microwave ovens 1000W
4. Washing machines 360W
5. Rice cooker 500W
6. Juice extractor 200W
7. Electric fans 65W
8. Refrigerators 130W

This is a common equioment of tiny house. The largest load we see is induction hobs 1800W, but the time of using induction hobs is usually very short, we estimate the daily usage time to be one hour, which means it requires 1.8kWh of electricity. Microwave ovens are calculated to be half an hour and 0.5kWh of consumption. Washing machines are used half an hour every 2 days, a total of 0.09kWh per day. Rice cooker is used twice a day for half an hour each time, which is worth 1kWh. Juice extractor is used for one hour every day, totally 0.2kWh. The lamp is used for 5 hours which is 0.25kWh. Electric fans is 10 house for 0.65kWh. Refrigerators, 24 hours for 3kWh. After we are clear about those, we can calculate how many batteries are needed.

No.LoadPowerkWh/day
1Led lights50W   0.25
2 Induction hobs1800W1.8
3Microwave ovens 1000W0.5
4Washing machines 360W0.09
5Rice cooker 500W500W1
6Juice extractor 200W0.2
7Electric fans 65W0.65
8Refrigerators 130W3
Total:7.49

We calculate that the electricity used in a day is 7.49kWh, when configuring the battery, we need to configure a 15kWh battery. After knowing the battery capacity, we calculate how many watts of the solar panels are used. Assuming that our sunshine time is 5 hours per day at full load, and the max. allowable charge of the battery is 150Amp (1C), but because there are 5 hours of sunshineevery day, we can fully charge the battery in 5 hours, so a 3kw solar panel is enough. It is enough to use 48V system equipped with a 60A MPPT solar charge controller and 3000W pure sine wave inverter, which can meet the power supply of the whole house.

1. 3000W solar panel
2. 60A Mppt solar charge controller
3. 3000W pure sine wave inverter
4. 51.2V 300Ah LifePO4 battery

This confihuration can basically meet the daily needs, even if there is no sun for two consecutive days, you can still supply power normally. Of course, if your load is not that much, you can reduce the configuration appropriately. And installing sucn an off-grid solar system, it will be completely free, without any additional electricity bills.

See more for 12 Best Design Of Off Grid Solar System Guide 2022 >>
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