Solar Inverter Buyer’s Guide

Read the following material will help you broaden the understanding of the solar inverter. It also helps you better manage renewable energy systems and address the problems that may occur in the system. If you intend to design and install the system, then you’ll want to know as much as the knowledge of the inverter. Here are some important factors to consider when selecting the solar inverter.

System voltage

When buy a off-grid inverter, you need to select a input voltage and battery voltage inverter to match your system. As mentioned earlier, wind power, solar power and micro hydro power system voltage is usually 12v, 24v or 48v. In smaller applications, such as small hut or summer cottage, 12v system is very common. Civil systems usually voltage 24v or 48v.most are 48v, because 48v is most efficient.

System voltage refers to renewable energy technologies (PV array, or micro-hydro turbine generating electricity voltage). In other words, photovoltaic arrays or wind turbines connect in accordance with 12v, 24v or 48v output voltage ,as same with the battery Group,so it also produces 12v, 24v or 48v output voltage. The solar inverter will increase the voltage to 120v or 240v AC .Since the off-grid energy systems all components are working in renewable at the same voltage, and power inverter and battery must match .24v voltage inverter do not work in the 48v system. If you plan to install 24v PV array, you’ll need a battery inverter 24v of 24v unit and battery pack. You can exchange with Inverter Go technical, ask us which one is the best suitable inverter for your system, it always doing good.

When selecting the inverter for grid-connected systems, you need to select a PV array match the Solar inverter.

Modified square wave and sine wave

The next factor you should consider is its output waveform when selecting an inverter. Off Grid inverter has two forms: Modified square wave (also often called modified sine-wave) and sine-wave.On Grid Inverter is a sine-wave inverter, so that it can match the power grid form.solar inverter set

Modified square wave power is a kind a rough approximation of grid power forms. But for most applications, such as refrigerators, dishwashers and power tools, it is a good form of energy. It also applies to most electrical equipment, including televisions, lights, stereo equipment, computers and ink-jet printer. Despite all of these devices can be operated in the form of poor quality energy, their efficiency will be reduced, and more serious fever (lights or water pumps, etc.), which is caused by a given input.

However, when the modified square wave supply sensitive electronic circuits, such as a microprocessor-controlled front door drum-type washing machine, the device having electronic watch, charger all kinds of wireless tools, copiers and laser printers. Problem appeared. These devices must work in the sine wave power. No sine wave power, That would be bad. For example, First inverter dan purchase is a modified square wave inverter, he found his front door frigidaire gallery energy-efficient drum-type washing machine does not work in this energy form. This washing machine control microcontrollers – Microcontrollers also control other similar models (except staber washing machine), can not work in this energy in the form of poor quality. Since dan replaced the sine wave inverter type , There have not encountered such problems.

Some laser printers performance is not good under modified square wave, as well as some of the chargers, ceiling fan and dimmer battery tools.

Worse, some electronic equipment, such as televisions and stereos, as long as it work in the modified square wave energy, it will send annoying high-frequency hum. Modified square wave energy may also cause nasty streaks appear on the TV screen, and damage sensitive electronic equipment.

Work under modified square wave energy, the microwave cooking will take longer time. In the modified square wave, instruments and equipment will appear more serious fever, life will be reduced. Computers and other digital devices work will happen more errors and catastrophic failure, the digital clock can not work as setted, the motor sometimes does not work at the rated speed. So why manufacturers produce modified square wave inverter?

The most important reason is the cost. Modified square wave inverter is much cheaper sine wave inverter, each will save you 30% to 50% of the cost.

Another reason of maintaining modified square wave inverter production is that they are very rugged. They require little care and can work for many years (related with their durable performance and simple structure: they are much simpler than the sine wave inverter on an electronic device).

Modified square wave inverter has two types: high-frequency switching and low frequency switching. In contrast, high-frequency switching is cheaper. For example, a typical high frequency switching inverter 2000w price is cheaper 20% to 50% than the low-frequency type. weight of High frequency type is lighter, and therefore it is easier to install. High-frequency inverter weight 13lb, and low-frequency type weight 501b.

Low-frequency switching-type modified square wave inverter compared with high frequency switching inverter,it costs higher, but also heavier, but these investments are worthwhile. One reason is that they usually have a higher anti-surge capacity. This means that they can transmit more energy surge, which is necessary for starting certain electrical equipment for the well pumps, power tools, dishwasher, washing machine and refrigerator. The Shorter start-up time take, the greater the surge needed.

Although there are some solid improvements square wave inverter on the market, we recommend that you buy a sine wave inverter for the off-grid system. There are many modern electronic devices in the home, and the sine wave inverter output is an ideal fit for the use of these devices. InverterGo company’s sine wave inverters are very good, and it is reasonably priced.

Output power, surge capacity, and efficiency

When selecting inverters, even if it is a grid-connected inverters, you also need to consider three additional factors:

Continuous output, surge capacity and efficiency.

Continuous output

Continuous output is a measure of the inverter output power under continuous operating conditions (if the system has enough energy available any). Inverter output power unit is w (watts), but some inverter is described by the current continuous output. The power conversion to electric current, you can refer formula: Power = current × voltage. For example, InverterGo sine wave inverter, model IG3000-1, continuous power 3000w. This inverter can easily while a microwave 1000w, 1200w of a hair dryer, and a few small load power (incidentally, “30” meaning the model number of the continuous output power of this unit It is 3000w). Continuous output inverter listed on this specification is 15a.

To calculate how much continuous power you need, you can put common electrical and continuous power together. Whenever possible and reasonable, usually only two or three large loads will work simultaneously. However, keep in mind that, in some cases, a lot of the load can work at the same time. For example, when run the dryer and the well pump, the dishwasher and the sump pump can run too. If you intend to open an stores close to home, and use the same power inverter, you may need a higher continuous output power of the inverter.

Surge Capability

Electrical equipment with motors, such as vacuum cleaners, refrigerators, dishwashers and power tools, are required to start the pulse energy. You can easily observe this: when someone opens a device, such as a vacuum cleaner when you can take a look at renewable energy systems installed in the meter, or look at the current watt meter on. If you look carefully, you will find there is a transient current spikes, which is needed to power the motor starter surge. Spikes usually only lasts less time ls, but even so, as long as the inverter does not provide enough energy to power tools or appliances can not start. That Can not start the problem is not just inconvenient, the motor will stall generate a lot of current, soon serious fever. Unless it is equipped with a thermal protection device, otherwise the motor will burn.

At the time of purchase of the inverter, make sure to check the inverter surge capability. All the quality standards of the low-frequency inverter design can ensure it can withstand short-term power surges, typically 5s or so. surge capacity or power surge of The instructions,  will be listed in the form of power or current.

Efficiency

when buying inverters Another consideration is the efficiency of the inverter. Calculated the energy efficiency :the input energy/output of the inverter.

Inverter efficiency is from 80% to 95% range, maximum efficiency of the most models are up to 90%. For example, a 92% efficiency of the inverter, the DC into AC 120v, it will lose 8 percent of the energy.

It should be noted that the efficiency of the inverter can change with the load. richard perez is a renewable energy expert, is also a “home power” magazine publisher, according to his introduction, in general, as long as the output reached 20% to 30%,the rated power of the inverter can reach the highest efficiency. For example, an inverter 4000w, when output exceeds 800 ~ 1200w, will reach maximum efficiency. Power is lower than this, it will significantly reduce the efficiency.

Inverter heat dissipation

Since the efficiency of the marine power inverter is not 100%, the solar inverter internally generate excess heat. An 90% efficiency ,at rated conditions of operation 4000w inverter will generate heat internally 400w (equivalent to the heat emitted by four 100w bulb). The inverter must isolated from the heat, otherwise it will be damaged.

Inverter heat sink and fan rely on isolation to reduce internal temperature.it Increase the area of ​​heat sink cooling fan ,which blowing through the internal module to dissipate heat. However, if the inverter is in a high temperature environment, That promptly dissipate heat to keep the inverter in a safe temperature conditions is very difficult.

The inverter often equipped with a thermal protection circuit. That is, the program will control the solar inverter when the internal temperature exceeds a set value automatically it will reduce the output (less electricity). With the power oscillator (h bridge) internal temperature Increases, the output current is reduced. In other words, this means that if you need a lot of power, but the solar inverter internal temperature is very high, your needs will not be met. For example, a solar inverters, in 77of (25 ℃) at up to 100% continuous output, but in 117.5of (47.5 ℃) output has dropped 60%.

This data has many meanings. First, the solar inverter must be installed in a relatively cool location. dan inverter installed in his room Utility, and it was his muddy house coolest places on earth. Second, Do not mount the solar inverter into a box to isolate noise (though not all inverters are noisy). Third, be sure to buy a good heat dissipation of the solar inverter. Ideally, you need a natural cooling of the solar inverter can, that is a inverter can cool itself not consuming power. Many off-grid inverter has a cooling fan, for example, in a balanced charging.

The IG Series inverter has a die-cast aluminum housing equipped with fins, can naturally dissipate internal heat. On some models, the internal circuitry is fully encapsulated so that it can be isolated from the outside to prevent dust, moisture, insects, and may damage the inverter little mouse intrusion. However, That models equipped with vent holes allow outside air to flow through the interior of the electronic device may improve the performance of the inverter. Such models produce more than the enclosed AC power, Solar inverter have a better performance in high-temperature environment.

Battery charger

Most standard household battery inverters are equipped with a battery charger. So, if you plan to install off-grid system, or with a battery back-up with network-based system, be sure to select an inverter with a battery charger. With it you can use from the grid (with battery backup for the grid-system) or a generator(For off-grid systems or with a battery backup and grid-system) AC to DC battery pack.

No matter which inverter you choose, keep in mind that the inverter battery charger must be charged within a reasonable period of time. In addition, the capacity of the generator must be sufficient charging current and the current workload needs all the room needed to provide chargers.

The solar inverter can be installed and to be installed outdoors indoors. Most inverters installed in a weatherproof shell, just as mentioned before, all solar inverters need to avoid too low or too high a temperature. Many on-grid inverter rated ambient temperature -10of. Off grid inverters or hybrid inverters are usually installed indoors, so you can leave the battery recently, reducing line losses (as described above, the battery needs to “live” in a warm space). Most grid-connected inverter is installed in a room off the main circuit breaker panel near the place. Power transmission line is the introduction of housing from the main circuit breaker panel at the (most solar inverter manufacturers recommend their installation at room temperature).

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