How to Choose a Portable Power Station? (Solar Generator Buying Tips)

As portable power stations are getting popular among outdoor enthusiasts, emergency preppers, and professionals, more and more people are willing to keep one or more with them when they are on the go, at home, or at work.

Despite this becoming the new normal, I have had a lot of complaints from friends that their portable power stations don't meet their expectations. The most critical problems were the inability to run their most power-hungry devices, short uptime time and their lack of customer support. Some of their other concerns were long charging times, noise, size and weight. In fact, most of these problems arise only because they choose the wrong model for their needs.

With new brands and new products emerging, there are hundreds of offerings to choose from in the market. Then, when we need to make a purchase decision, the question becomes: Which model is best for my needs and budget? I am here to help you choose a portable power station that meets your needs.

portable power station - Growatt

What Is a Portable Power Station?

First, we need to know what a portable power station is. Simply put, a portable power station is a rechargeable battery-powered inverter generator. In many cases, people also call it a solar generator as it supports charging with solar panels. A portable power station is similar to a power bank in that it consists of a battery and offers multiple outlet options. Most portable power stations on the market use Lithium-Ion batteries, and support various charging methods such as wall charging, solar charging, and car charging. Often they come with USB-A ports, USB-C ports, car cigarette lighter ports, and AC outlets for convenient charging.

Understanding The Basic Specifications

Battery Capacity: Watt-hour (Wh)

Watt-hours are a measure of battery capacity. With the same discharge devices and environment, a larger battery capacity means you can use more power on a full charge and run the same devices for longer.

A watt-hour is the most basic specification for a portable power station because it not only indicates battery capacity, it also decides the size, weight, and price of your portable power station.

Some people would prefer a larger capacity because it can run more devices for longer, which is true when it is used as a home backup solution, but not always when it is used as a power source outdoors. Lithium-ion batteries are very heavy, taking up roughly 60% of the size and weight of a portable power station, and when the weight of a power station exceeds 20KG, it is no longer considered “portable.”

From a purchasing standpoint, the capacity of the battery also decides the price base of the power station. The battery is the main cost of a portable power station, and most other features have a less significant impact on cost.

In most cases, the output power level is correlated to your capacity, which will decide the type of devices you can power and charge. Here let’s see what to look out for when choosing the right output power level.

Power Output: Watt (W)

Watt is a measure of your power output. This usually indicates the total AC output power of your portable power station and determines what devices you can run with it. You can use it to charge or run your device only if the rated consumption in watts is within the output power range of the portable power station. Any device or appliance with a higher rated power consumption will trigger the overload protection mechanism and force the portable power station to shut down its AC output for safety reasons.

As mentioned earlier, the power output of a portable power station is correlated to its capacity. This is limited by the cell performance of the battery. Most portable power stations only support a 1:1 discharge rate, which means you will find a portable power station with 1000Wh can only run 1000W of output. Some portable power stations with high discharge rate batteries and better inverter technology can support a 1:1.3 discharge rate. For example, Growatt’s infinity 1500 portable power station has a capacity of 1500Wh and outputs 2000W, which will enable it to support more types of devices and appliances than other products at the same level of battery capacity.

Battery Chemistry (What are NMC & LFP?)

In addition to battery capacity and power output, you also need to know what type of batteries your portable power station uses. Battery chemistry comes into play here. The most common battery chemistries you find in the market are NMC and LFP.

NMC (also known as NCM) stands for Nickel Manganese Cobalt, and LFP is short for Lithium Iron Phosphate. The two battery chemistries have different chemical structures and therefore have different energy densities, different chemical stabilities and different lifetimes. Let’s compare the performance of the two:

Battery Chemistry

NMC (NCM)

LFP

Chemistry

Nickel Manganese Cobalt

LiNiMnCoO2

Lithium Iron Phosphate

LiFePO4

Density

Higher

Lower

Size & Weight (w/the same capacity)

Smaller and lighter

Larger and heavier

Stability

Lower

Higher

Safety

High

Higher

Lifecycles

Shorter

Longer

Charging Methods and Speed

Most portable power stations support three basic charging methods: wall charging, solar charging and car charging. Some might say they also support other charging methods like generator charging and EV charger charging, but these mostly use the same wall charge and solar charge input ports.

Wall Charging:

Wall charging is the most commonly used method for short trips or home backup, making wall charging speed an important feature to consider when you make a buying decision.

All the batteries in the world operate with direct current (DC). Before power can be charged into the battery, it must be converted from AC (Alternating Current) to DC.

Charging with an AC-DC adapter
Many portable power stations use external adaptors to accomplish AC-DC conversion outside the product. However, limited by the technical barriers, this wall charge method usually requires a lengthy 5-8 hours to fully charge.
Charging with Bidirectional Inverter Technology
Fortunately, more advanced bidirectional inverter technology is now applied to some high-end models to support faster wall charging. This technology can complete the AC-DC conversion inside the power station and allow the battery to intake more power when charging. Portable power stations with bidirectional inverter technology can sometimes charge from 0-80% in 1 hour and be fully charged in just 2 hours. This new technology also makes wall charging more convenient by eliminating the need for bulky AC-DC adapters. Growatt’s Infinity 1500 Portable Power Station features bidirectional inverter technology to provide full capacity in less than 2 hours, getting you ready for any anticipated or unexpected power needs!

Solar Charging: 

Since portable power stations support charging with solar panels, they are also widely known as solar generators.

Solar charging is the most important charging method for off-grid users and during prolonged power outages. The advantages of using solar as an input source include grid independence, free natural power source, no noise, no odor, and no harm to the environment. Solar charging gives a lot of benefits, but most models only allow very limited solar input, making this method of charging a long wait. The ideal solar charging time is 5 hours as it is most efficient for solar harvesting from 10 AM to 3 PM. However, most solar generators in the market require 5-10 hours of solar charging time.

It is well known that solar energy harvesting is greatly affected by environmental conditions. Panel angels, cloud coverage, temperatures, and other factors can make a significant impact on solar panel yields. Despite this, there are ways to improve solar charging efficiency in certain environments, and that’s where Maximum Power Point Tracker (MPPT) plays an important role. As its name suggests, MPPT is a technique to maximize solar power transfer at the highest efficiency as charging conditions change.

Growatt is a well-known brand in the PV inverter market and has matured MPPT technology that supports conversion efficiency up to 99%. With advanced MPPT technology, Growatt’s Infinity 1500 solar generator has superior solar performance over other models on the market, allowing users to finish charging in 2.5 hours with 800W solar input. This allows users to quickly get green energy anywhere without relying on the grid.

how to choose a solar generator

Before making a purchase, you need to consider….

  1. Your Purpose: People purchase portable power stations for a variety of purposes. Outdoor enthusiasts use portable power station as an outdoor power source for picnics, camping, or short expeditions; off-grid livers may need it for road trips, RV living, or as a power source for off-grid homes; Emergency preppers see it as a necessary power backup; Professionals like DIY makers, photographers, bands, etc. prefer it as a convenient and portable power supply. Different purposes determine how often you use it (lifecycle), how long you need to run it (capacity), what device you need to power (output power), what methods you can use for charging (charging speed) and how you will transport your power station (weight and dimensions).
  2. Devices and Appliances: You must know what you are going to power. Different electrical devices run at different output power levels. A portable power station can only support devices that are within its allowable range. If you just want a portable power station to charge mobile devices, a digital camera, and lighting for  short trips, a 300W output might satisfy all your needs. But if you are expecting continuous power for your household refrigerator or electrical stove during a power outage, you will likely need a model that supports more than 1800W to run all your devices.
  3. Number of Devices: For those who occasionally travel alone, they can be easily satisfied with the number of outlets that most models offer. But for those who prefer family parties or off-grid living, have more devices to charge at the same time. Lack of outlet availability can often leave devices waiting in line.
  4. Discharging Hours:You need to ask yourself: How long will you need power from one full recharge? Although sometimes the output of your portable power station can charge all your devices, that doesn’t mean it’s going to run forever. Once you run out of batteries, the power station will stop working. In some cases, you won’t have a chance to charge again after a long period time. So how do you know how long your devices can run? Here’s a general formula for calculating discharging time: 

    Discharging time = Stated battery capacity * Usable percentage (usually 80%~82%)/ rated power of your device 
    *Usable percentages
    1) Portable power stations usually keep 10% of the battery unused to avoid draining and damaging the battery.
    2) Efficiency loss due to inversion.

  5. Available Charging Methods:In some cases, only certain charging methods may be available. For example, for those who live off-grid, wall charging is not an option; for those who need to be outdoors for short trips or work, solar charging is not the best option; for those who are on the road most of the time, car charging would be ideal. Different models support different charging methods at different speeds. When you're making a buying decision, you'll want to look at these features to make sure the charging method and speed are what you want.

Other Things to Look at:

  1. Size & Weight: When you are using a portable power station outdoors, portability will be one of your main considerations. Lighter and smaller generators are easier to transport.
  2. Number of Outlets: It's better to have more outlets for charging so your devices don't have to wait in line. Otherwise, you may need to purchase additional power strips to expand additional outlets.
  3. LCD Display: Make sure the LCD display provides all the necessary information you need! The more information it provides, the better you can understand your use of power.
  4. UPS Feature: An Uninterruptible Power Supply (UPS) provides ultra-fast switching from the grid to the battery in the event of a power outage, providing reliable backup power to keep all critical equipment running in the event of a grid outage.
  5. Pass-Through Charging: Pass-through charging can charge and discharge the portable power station at the same time, which is especially useful when you need a continuous power supply.
  6. Smart Control: Some models support a smartphone app to realize remote access, monitoring, control, management and upgrade. With an app, you can learn about your power usage and device status, turn your power on/off at your fingertips, and set your own power usage rules.
  7. Warranty Policy: Different brands offer different warranty policies. Check out their warranty policy to make sure your portable power supply is well cared for after purchase!
  8. Customer Support: Brands need to provide multiple channels of contact to ensure they're always accessible when you have issues. It would be best if the brand you buy from has local customer support that you can always contact.
How to Choose a Portable Power Station - Growatt

Finally! Choose a Brand That You Can Trust

Choosing a brand with a good name is important. Well-known brands usually offer better quality products and better customer support. Since they usually go through rigorous quality checks before putting the product on the market, there is less chance of something going wrong with the product. They have better customer support that is always accessible and helpful, even if you have questions while purchasing. However, smaller brands mostly lack the capital and local resources to build such a system and provide related services, and you may end up in a helpless situation.  

To understand the brands, search for their brand names using search engine tools. Check out their websites and learn about their business. Make sure they have good business practices and no bad news. Also, check for people's comments to see what they talk about the brand, the products, and the services.

Hope my sharing today can help you choose the right product! For more portable power station / solar generator products or experience sharing, go and take a look at Growatt’s website and check our latest products and updates!