Solar Power Stations
The modern Solar Power Station compiles dozens of technical components into a seamless plug-and-play unit. The basic function of the power station is to accept power, store it, and supply it, with minimal user input required. Some of the most important components enabling this seamless exchange are listed below:
Inverter - The heart of most solar power systems. Why? Because photovoltaic solar panels generate DC power, but most of your devices require AC power. The inverter converts DC power into AC power. In every inverter, some power (ex. ~ 10 - 20%) is lost in this conversion process. Every inverter has a continuous power rating (ex. 3000 W) and a peak power (a.k.a. Surge power) rating (ex. 6000 W). The continuous power rating is how much Wattage can be sustained continuously without harming the inverter. The peak power rating is how much Wattage can be sustained for a brief moment without harming the inverter. Oftentimes, the peak power output can only be sustained for a fraction of a second. It is useful to have a high peak power rating for certain appliances. For example, electric air compressors are well-known for requiring 5 times their rated Wattage during their initial power-up. In conventional inverters, peak power rating is about double the continuous power rating. Low-quality inverters will not perform as well as stated. High-quality inverters will perform at least as well as, if not better than, their rating.
Battery - This is what supplies your electricity when the sun isn’t shining! Out of all power station components, the battery has seen perhaps the most impressive innovation in recent years. For the cost-conscientious consumer, tried-and-true AGM batteries are better than ever. But the most significant recent innovation has been in lithium-ion batteries. Modern lithium-ion batteries are safe, reliable, high-capacity, lightweight, and long-lasting. 2,000+ life-cycles are the new industry standard for lithium batteries. All power stations require a well-engineered Battery Management System (BMS) to charge each individual cell appropriately.
Maximum Power Point Tracking Solar Charge Controller - This MPPT Charge Controller manages the interface between the PV array and the BMS. The MPPT technology ensures that energy is not being wasted in the exchange.
Case/Inputs/Outputs - The entire system should be assembled into a well-integrated and durable case. An intuitive user interface should allow the user to control the unit without hassle. And at the end of the day, functionality comes down to what can go in and out of a Power Station. It is important to have plenty of AC and DC input/output ports supported by adequate circuitry. AC input/output amperage limits should be as high as possible. A battery expansion port is a useful tool for high-capacity power stations, giving the user flexibility in sizing power banks. Good power stations feature the ability to charge from and relay (i.e. “pass-through power”) AC input power, thereby enabling the user to completely utilize grid power when it is available.
Safety Protections - A good power station has its limits. Voltage and amperage input/output must stay within their allowed ranges. But, accidents do happen. What if a PV array is sized wrong? What if too much power is drawn to power a device? What if a device short-circuits? A good power station will not be damaged by these commonplace accidents. Built-in protections safeguard against them, notify the user that something is wrong, and prevent any harm being done to the unit, the devices, or (especially!) the user.
Choosing a Power Station - It is important to consider all specifications of a unit and determine if it meets your power needs. The most important figures are kWh of the battery bank and kW of the inverter. After that, ensure the power station has the input/output ports you require. If it all checks out, carefully consider the PV input ranges of the power station and make sure it corresponds to your intended PV array.
For example, let’s say a Power Station specifies a PV input voltage range of 60 - 150 V and a maximum array Wattage of 1500 W. This means that, for example, a maximum of 5x 300 W solar panels may be used to stay under the wattage. But if each solar panel has a voltage of 75V, how can they all be connected? Connecting them all in series would generate a voltage of 375V, above the allowed input range. Connecting them in parallel would keep the generated voltage at 75V, which is within the allowed input range. It is important to carefully plan your PV array in accordance with your power station.