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If you want to live off the grid you’ll need a lot of solar power. Fortunately the costs continue to drop so even 3000W / 3kwh systems are within reach. The question of course, is whether a 3000W solar system is enough for your needs. There are many factors to consider but there’s a lot you can do with here.
A 3000W solar system can run appliances in a small, 2 bedroom house including a TV, microwave, refrigerator, fans and lights. A 3750W inverter is required for solar systems with a 3000W rated output.
Appliances That a 3000W Solar System Can Run
The following is the estimated consumption of various appliances and devices. Check your appliances for the specific watt consumption. To get the watt hour usage per day, multiply the watts on the table by the number of hours you use the device.
|Blender||500||DVD / Blu Ray Player||15|
|Coffee Maker||1000||Cable box||30|
|16 Cubic Feet Refrigerator||1300wh/day||Gaming Console||150|
|Cooling and Heating||Office|
|Ceiling Fan||120||Desktop Computer||200|
|24000 BTU Central AC||4000||Printer||100|
|1000 0BTU Window AC||3300||Tablet||8|
|Electric Water Heater||4500||Router / Modem||7|
|Electric Water Heater (tankless)||18000-20000|
|Iron||1200||100W LED bulb||20-25|
|Gas Clothes Dryer||1800-2000||Humidifier||200-250|
|Electric Clothes Dryer||3000||Hair Dryer||1200-1500|
There are some things you need to keep in mind when computing total wattage use. Some of these appliances use less power than the stated figure. For example, a coffee maker will only consume 1000W if it’s used for an hour. In truth you probably run it for just a few minutes a day. A 300W stand mixer draws only 25W if used for just 5 minutes.
Desktop computers, laptops and TVs consume power even when turned off. Refrigerators need a lot of solar power to start up, but the running watts is lower. Refrigerators also go into on/off cycles to keep the required temperature.
Is a 3000W Solar System For You?
There are two methods to find out.
The first is to use add the total watts of every appliance you use. You can use the charts above as a guide but you should always check the specs on each appliance to be sure.
The second way is easier. Look at your monthly bill and how many kilowatts you use. If it’s at 20kw or less per day, a 3000W system is enough. But if it’s more than that you should consider a bigger solar array setup. In case your monthly bills vary, get the average and you will know how much is required.
Do take into account times when your consumption is higher. You might use more power during the summer as the fan or AC is running, or the heater is more active during the winter. Remember that solar system output goes down during the winter so include in your calculations. Get a solar generator or several high capacity options like the CHINS 100AH lithium batteries if you think it won’t be enough.
How Many Solar Panels to Run a 3000W Solar System?
The average solar panel is 250W. 250 x 12 = 3000, so you need 12 panels, right? Actually you will need 15 solar panels to run a 3000W system. Here’s why.
Solar panel ratings are based on peak output. So when a panel is rated at 250 watts, that is peak performance. But orientation, location, panel angle, sunlight availability affect the results. Bottom line is, solar panels don’t always reach peak output.
Can a solar panel reach the full 250W in direct sunlight? Yes it is possible, but when the sun angle changes, the level drops. Even under direct sunlight, factors like temperature affect performance. The hotter it is, the lower the energy collected. The cooler it is, the better the panel’s performance. Solar panel rating also does consider energy losses in the inverter. The distance between the solar panel and battery cables also results in energy loss.
Most 250W solar panels reach up to 85% of its rated output, or about 200W. A 250W solar panel that produces 200W is good for 1000W daily with 5 hours of sunlight. 200 x 15 = 3000. And if the panels produce more than 200W, you can store the excess energy in a battery for reserve.
If you have 300W or larger panels, use the same formula. Multiply 300 x 85% = 255 (or whatever is the output efficiency rating of the panel). A 300W solar panel can produce 255W, so 12x 300 solar panels generates 3000W.
By the way, you may have seen solar panels with 18%-25% efficiency ratings on them. That does not mean the panel only reaches 18% of its capacity. That rating refers to the percentage the panel can extract from the panel’s solar gets. In other words, the 15%-23% refers to the amount of sunlight the panel can harvest from the total energy that strikes its surface.
Do You Need Batteries in a 3000W Solar System?
No, batteries are not required to reach 3000W output. Where the batteries are needed is to store the excess power produced by the solar panels. The battery’s reserve power allows you to run appliances at night or when it’s raining / cloudy. When the battery gets depleted you charge it in the morning with the solar panels or a wall outlet.
Battery capacity is measured in ah (amp hours).
Amps x volts = watts
Watts / volts = amps
A 12V 300ah battery gives you 3600W. Three 100ah 12V batteries also gives you 3000W. The higher the voltage (24V, 35V) the lower ah capacity required. However, batteries (lead acid in particular) should have a 50% DOD (depth of discharge). That is, you should recharge the battery when the power goes down to 50%.
Emptying the battery is not good for its life cycle and it must be maintained properly. That is why you have to double the capacity to use 3000W without emptying the battery. So you’ll need a 12V 600ah battery or six 100ah 12V batteries. Any combination of ah capacity and battery voltage will do as long as there is 300ah capacity when used at a 50% DOD.
What Inverter Size For a 3000W Solar System?
Inverters come in various sizes, but the basic rule is it should be at least equal to your system’s DC rating. inverter size is measured in watts so it’s easy to compare the two. In a 3000W solar system you need at least a 3000W inverter.
However, inverters are not 100% efficient so you need to account for this. To be safe, the inverter should be 125% of the system’s load. With a 3000W solar panel that would be 3750W. The Giandel 4000W Pure Sine Wave inverter will do nicely here.
That is a 25% safety margin which should be enough. Don’t get an inverter that’s too big because it will not be as effective. If running powerful appliances like refrigerators and air conditioners, a 50% safety margin is not unheard of.
How Much Power Can a 3000W Solar System Produce?
It comes down to how efficient your solar panels are. Using the example above, a 250W can realistically produce 200W. With 5 hours of sunlight that’s 1000W per day. With 15 solar panels expect around 15000W or 15kw daily under ideal conditions. The level will drop off during the fall and winter. This is where you will find that battery or solar generator useful.
What is the Cost of a 3000W Solar System?
A 3000W solar system costs $6000-$8000. This does not include the installation cost, though homes that install solar panels are entitled to various tax credits and rebates. As to how long before this investment pays off, it can be from 7-20 years. The reason for the wide range is electrical usage varies greatly. Simply put, the more you use solar power, the faster it is going to pay off.
Installing a 3000W solar system is a serious undertaking. It is not just about the cost but also the time it takes to put the entire thing together. if you’re going to need this type of power, go over your requirements thoroughly to ensure that is is sufficient. With this kind of power though, you can really live off the grid.