How to Charge a Lithium Ion (Li-Ion) Battery

Lithium-ion batteries are among the most common rechargeable battery chemistries used today.

They’re in smartphones, electric vehicles, and solar power systems. EcoFlow uses a new subset of Li-ion batteries — lithium iron phosphate (LFP/LiFePO4) — in many of its products, such as most portable power stations, Smart Devices, and Power Kits.

Both traditional and LiFePO4 batteries typically have multiple charging options. Each method presents unique benefits.

Learn the most common ways to charge lithium-ion batteries and how to safely and effectively recharge your Li-ion battery below.

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5 Common Li-Ion Battery Charging Methods

If you have a lithium-ion battery powered device, you’ll need to know how to charge it properly. Plugging into an AC wall outlet is typically one way, but it’s not always the most efficient. It’s also not an option when you’re off-grid.

Lithium-ion batteries typically charge in one or more of five ways:

  • AC (household) electricity
  • DC power (often using a car or motorhome adapter)
  • USB-C
  • Solar panels
  • EV charging stations

Lithium-ion batteries undergo a similar process in each of these charging methods: lithium ions are released by the cathode (the positive electrode) and received by the anode (the negative electrode).

The method you choose can impact charge times and the battery’s lifespan.

Read on to find out how the different lithium-ion charging methods work.

1. AC Power (Household Electricity)

The most common way to charge up a Li-ion battery is with AC power using a standard wall outlet in the home. Simply plug your device into the outlet with the appropriate cable or cord that it came with.

Remember that if you’re travelling overseas, different countries use different wattage and voltage to power electronic devices. Most portable devices like smartphones and laptops can handle all the common electricity currents worldwide. However, many appliances cannot.

Before using an AC plug adapter to hook up a device outside your home country, ensure it’s compatible with the local current. Otherwise, you could damage or destroy the device.

2. DC Power (Car Adapter)

DC power, usually supplied by a car or motorhome adapter, is another common way to charge Li-ion batteries, and this method works with various types of devices. DC charging typically requires a cable that plugs into the device and the car or other vehicle’s 12V DC outlet.

It’s crucial to note that charging a Li-ion battery with DC power when your vehicle isn’t running can quickly drain your car’s battery. Also, ensure that the voltage of the adaptor is compatible with your device’s DC input rating to avoid damaging the battery.

3. USB-C

Often, you can also power your lithium-ion battery using a USB-C port. USB-C ports are becoming a universal standard, replacing older micro-USB and USB-A ports on most small electronic devices.

USB-C offers greater power transfer than the previously common USB-A port.

To use this method, simply connect the device to a USB power source such as a laptop or desktop computer, an external battery pack, or a wall adapter.

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4. Solar Panels

Solar panels are becoming a popular way to charge Li-ion batteries, allowing users to generate electricity using sunlight as a renewable energy source. You can charge your Li-ion batteries using solar panels by connecting the battery to the panel system following the instructions from the manufacturer.

Solar panels are relatively easy to set up and use, but their efficiency may vary depending on several factors.

Also, note that the warmth and direction of the sunlight will likely impact the amount of energy produced, so it will sometimes vary. The best way to increase the charging speed of your battery when using solar panels is to ensure the panel or panels are always in direct sunlight while charging.

EcoFlow’s Portable Power Stations and many of its smart devices offer the above four charging methods. All current PPS models use long-lasting LiFePO4 batteries. You can charge them via your car adapter, USB-C port, AC (household) electricity, or solar power by connecting them to our solar panels.


5. EV Charging Stations (240V)

Electric vehicles utilise lithium-ion batteries, and an increasing number of new EVs now use LiFePO4 batteries due to their many benefits compared to Li-ion.

Given lithium-ion chemistry’s ubiquity, EV charging stations can obviously charge Li-ion and LFP batteries. However, EVs consume and store a huge amount of electricity. Very few consumer devices and electronics can recharge using an EV station.

There are two phases of charging a lithium-ion battery with an EV charger: the constant current phase and the “topping charge” phase. Each is important. The constant current phase is much faster and can quickly get the battery up to about 80%.

Then, to get the battery from 80% to 100%, it will enter a topping charge phase, which is much slower to avoid overheating — this is critical. Covering this small percentage of battery power (such as from 80% to 90%) can take just as long as it took to go from 40% to 80% battery.

You cannot charge most Li-ion batteries using an EV charging station. For example, only EcoFlow’s highest capacity solutions —the DELTA Pro Portable Power Stations and Power Kits — are compatible with EV charging,

Frequently Asked Questions

Are LiFePO4/LFP Batteries and Lithium-Ion Batteries the Same?

While both types of batteries use lithium ions, LFP batteries are a much newer subset of Li-ion batteries with different chemistry and benefits. LFP batteries are safer and longer lasting than other Li-ion options.

They also don’t use cobalt, which requires dangerous and unethical mining to source the materials.

What Voltage Should I Use to Charge My Li-Ion Battery?

The voltage for recharging lithium-ion batteries can vary depending on your location and the input capacity of the individual device. The minimum and maximum voltage required to fully charge your Li-ion battery without risk of damage should be clearly stated on the manufacturer’s label, the product manual, and the manufacturer’s website.

If you’re unsure whether your device can charge or operate at a specific voltage, double-check before you plug it in. Otherwise, you can damage or destroy your device.

Should You Leave a Li-ion Battery on Charge All the Time?

No, you should unplug the lithium-ion battery from the charger as soon as it’s fully charged. Some lithium-ion batteries even have the potential to explode if left to a charging source while already fully charged. It’ll also decrease the battery’s lifespan and performance if it’s always connected to a charger.

Final Thoughts

A Li-ion battery powered device with multiple charging options offers you greater flexibility to use your devices at home or off the grid.

Luckily, most devices that rely on lithium-ion batteries can recharge using multiple methods. Some methods — such as household AC power — require on-grid electricity.

Devices with a solar input for PV panels allow you to generate off-grid electricity from sunlight to charge your lithium-ion and LiFePO4 powered devices.

Knowing how your device’s charging methods work and protecting your battery during charges helps ensure your battery delivers peak performance and lasts you for years.

If you’re looking for reliable off-grid power solutions that use Li-ion and the latest LiFePO4 battery chemistry, check out EcoFlow today.

EcoFlow is a portable power and renewable energy solutions company. Since its founding in 2017, EcoFlow has provided peace-of-mind power to customers in over 85 markets through its DELTA and RIVER product lines of portable power stations and eco-friendly accessories.


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