If you’ve been shopping for a portable power station, you may have noticed that many sellers utilize vague terminology when describing how long one unit can last. Whether it comes to cycle life or watt-hour energy ratings and how long it can power one’s devices, the truth is, that the answer will depend on which perspective you’ll be looking at.
How to Define ‘How Long Does One Last?
There are two basic aspects to consider when defining how long a portable power station can last:
- How long a power station will be able to power one’s devices;
- How long the power station itself will last.
To begin with, let’s distinguish these terms, because they define fundamentally different characteristics.
How Long Will It Power My Devices? Calculating Runtime per Charge
Every power station will have a certain battery capacity, usually measured in watt-hours. A typical portable power station can range from 500 Wh to 2500 Wh or more, with home backup generators often featuring tens of thousands of watt-hours in battery capacity.
The duration of a single charge, in turn, depends on the battery capacity divided by the power consumption of one’s devices. For example, a 500 Wh power station will be able to power a 50 W camping fridge for ten hours. In practice, this number will be slightly lower due to various losses during the inverter process, but generally, the calculation is rather simple. As a reference point, you can use the following table:
Device Wattage Phone charge 5 – 20 W Laptop 40 – 90 W Small fan 30 – 50 W Mini camping fridge 40 – 100 W CPAP machine 30 – 60 W Space heater / Hair dryer 800 – 1500 W
Therefore, a 1 000 Wh power station will be able to keep your phone charged for days, power a laptop for ten or more hours, and allow you to run a mini camping fridge for the better part of a day. At the same time, it will only be able to power a space heater for less than an hour. It is critically important to understand that the higher the devices’ power consumption, the shorter the runtime of a power station. Therefore, when choosing a unit, it is a good idea to review the wattage of one’s devices to estimate roughly how much battery power they will consume.
Temperature plays a role as well, as extremely cold temperatures will reduce the battery capacity of a power station, decreasing its runtime.
How Long Will It Last? Battery Cycle Life
The second part of the question concerns the lifespan of a power station. Generally speaking, there are two types of lithium batteries, commonly used in power stations: lithium-ion (NMC) and lithium-iron-phosphate (LiFePO4). The latter type is also sometimes referred to as LFP.
Lithium-ion batteries are generally lightweight, inexpensive to produce, and relatively cheap, but they have a rather short cycle life of 500 – 1 000 cycles. A cycle, in this case, refers to a full discharge of a battery from 100% to 0%, although partial discharges also impact the overall cycle life.
On the other hand, LiFePO4 batteries are generally heavier, more expensive, and somewhat less energy-dense, but they can offer a much longer cycle life of 2000 – 3500 cycles, with some manufacturers claiming even more. Due to this advantage, many manufacturers are shifting towards LiFePO4 batteries with their power stations. For reference, a LiFePO4 battery, which can offer 3 000 cycles, will theoretically last for 30 years if discharged once a week (3 000 / 52). In practice, however, other parts of a power station, such as the inverter and wires, will likely fail long before the battery does.
It is also important to note that at the end of discharge cycle life, a battery will generally retain no more than 80% of its original capacity. Therefore, you should expect your 1 000 Wh power station to potentially hold up to 800 Wh after several hundred discharge cycles.
What Shortens the Lifespan of a Portable Power Station?
There are several common ways of shortening the lifespan of a power station:
- Full discharge – discharging a power station to 0% will put more strain on the battery than partial discharges;
- High operating temperatures;
- Storing a power station at 100% or 0% charge for a long time;
- Using a low-quality or non-original charger;
- Charging the power station at unnecessarily high currents.
Generally speaking, the faster you charge a power station, the more heat will be generated during the process. Excess heat, in turn, will hasten the natural discharge cycle life of a power station. Therefore, it is generally advisable to use standard charging methods rather than fast charging when your power station is not due for immediate use.
How to Make It Last Longer?
At the same time, several common-sense precautions will help prolong the lifespan of your power station:
- It is best to store a power station in a dry, temperate room, away from excessive heat and cold;
- If a power station is to be stored for a long time, it is best to periodically check its charge level and ensure that it is neither at 0% nor at 100% if possible;
- Avoid keeping a power station at 0% when possible;
- Avoid using low-quality or non-original chargers and power supplies;
- If the power station features an economy mode, it is best to use it for everyday, low-power applications.
Final Thoughts
A portable power station can provide power from a few hours to several days, depending on the connected load, while the lifespan of the product itself can range from tens of thousands of discharge cycles to merely several hundred.
Obviously, lithium-iron-phosphate batteries will outlast lithium-ion batteries by a decent margin. At the same time, several simple precautions, such as not exposing a power station to extreme temperatures or storing it at too high or too low a charge for a long time, will prolong the life of any power station. By reviewing the cycle life and battery chemistry prior to purchase, one can make a more informed decision on which portable power station to choose.
FAQ
1. How long can a portable power station run?
Runtime depends on battery capacity and device power consumption. A simple estimate is: Runtime ≈ Battery Capacity × Efficiency ÷ Device Power.
2. How long does a portable power station battery last?
Battery lifespan depends on battery chemistry, cycle count, temperature, charging habits, and depth of discharge. LiFePO4 batteries generally offer longer cycle life than traditional NMC batteries.
3. Is LiFePO4 better for a portable power station?
LiFePO4 is widely used for portable power stations because it offers long cycle life, good thermal stability, and reliable performance for frequent charging and discharging.
4. What can shorten a power station’s battery life?
Extreme temperatures, frequent deep discharges, prolonged storage at 0% or 100%, and improper charging can accelerate battery degradation.
5. How can I extend the life of my portable power station?
Store it in a dry, moderate-temperature environment, avoid unnecessary full discharges, use the recommended charger, and periodically check the battery level during long-term storage.
