How Long Does a Solar Power Bank Last?

Quick Answer

A Solar Power Bank of 10000 mAh can last around 2 to 3 days once it is fully charged. Remember that the discharge hours can be reduced if you frequently charge your electronic device.

Solar power bank charging would be depending on various factors such as sunlight exposure, location, time of the day, and the fast charging capacity of the solar power bank. 

How does a solar power bank work?

The solar power bank comes with a built-in solar panel to charge the connected batteries. The device is fully reusable, which means the battery connected to the power bank is rechargeable several times. 

Solar panels are made of photovoltaic cells preciously placed between the semi-conductive and glass layers to protect the panel. 

The device would have a positive and negative output connected to the battery’s positive and negative charge. The solar panel allows electricity production to flow freely from the solar panel to the connected batteries. 

portable solar power bank charging under sun light
A person holding a solar power bank under sun light

When sunlight strikes the solar panel, it frees the excess electrons, making them free to flow in the circuit. 

The electron moves from the positive charge to the negative charge in the device to complete the circuit. 

The conductive plate connected to the positive charge is direct the current to the batteries, where the electrons are collected, and the battery is put on recharging mode. 

Lithium-based batteries are widely used in solar devices.

The electron quickly moves from one side to another side of the battery when a sufficient amount of energy is applied to the material. Therefore, lithium-ion batteries are the first choice in solar devices.

What is the best time of day to charge a solar power bank?

Charging solar panels can be done at any time during the day. The day would decide how fast it would be charged like any other solar panel system.

However, if we were to recommend a time, then it’s best to charge between 9.00 am to 12 pm. Sun will be around the top and the outer temperature will not be too much during that time.

Once the temperature reaches its peak point, the solar panel’s efficiency would reduce due to high temperature. It will affect the performance of the panel, making them less effective.

When you keep your solar-powered power bank under direct sunlight, the sun rays hitting the panel free the photons, which start moving from the positive charge to the negative charge, and the circuit is complete. 

Your solar panel’s power generation capacity depends on the run light’s amount hitting the solar panel and exciting the photons. 

Is it possible to charge the power bank in the shade?

There are many misconceptions about solar power banks. Some believe the solar panel can be charged perfectly when there is a high temperature around.

Even in the shade, they say “you can charge the solar power bank due to excess heat in the atmosphere.” This thought comes back that says the heat is used to generate the power. 

Today, we knew that this is not the case. Solar power doesn’t produce electricity because of the high temperature. 

As a result, the solar power bank will not charge in the shade. Solar power needs direct sunlight to excite the photons and free them up so they can move freely. 

The direct sunlight would not reach the shade, resulting in less activated photons, and less flowing electronics would result in no charging.

However, the shade would not block 100% of the sun rays, so there will be a possibility that some portion of the sun rays would reach the panel, and they will do the job. 

A tree, for example, still has many small places or gaps between the leaves that direct the sunlight to the solar panel. 

In such a condition, the solar panel still charges the batteries and generates sufficient light. 

The charging would be slower in the shade and may take several more hours to get the power bank charged fully at its optimum capacity. 

Solar power bank charging time in direct sunlight?

Solar power banks are available in many shapes and sizes. The capacity of the solar power bank would affect the charging time. 

The capacity is measured in the milliampere-hours (mAh). The information about the power bank is mentioned on the packaging. The charging capacity may range between 2000mAh to 15000mAh or more.

The manufacture of the power bank indicates the charging time and the batteries’ capacity in the product specification. 

This helps you decide when to charge and how much energy you can store in the power bank.


1) PEALIKER (10,000mAh) – The power bank has a 10000 mAh capacity. It takes around 30 hours to charge under direct sunlight fully.

2) OUTXE (20,000mAh) – The power bank is developed for emergency use. The battery takes 50 to 70 hours to charge fully.

3) ADD TOP Solar Charger (25000mAh) 4 Panels – The power bank comes with a fast-charging capacity. Some users have claimed that the power bank can be charged in 4 hours under direct sunlight. However, the manufacturer has put the safe calculation of 25 to 50 hours for the full charge as the sunlight does not even occur during the day. 

Best Solar Power Banks

Power BankCapacityWeightSizeCharge Time
FEELLE Solar Power Bank25000mAh1.30 lbs6.1″ x 3.4″ x 1.4″25-30 hours
ADDTOP Portable Solar Power Bank24000mAh1.2 lbs6.1″ x 3.3″ x 1.2″30 hours
Hiluckey Portable Solar Charger24000mAh1.19 lbs6.1″ x 3.4″ x 1.2″35-50 hours
RAVPower Solar Charger25000mAh1.25 lbs7.1″ x 3.5″ x 1.2″85 hours
OUTXE Rugged Solar Charger20000mAh1.15 lbs6.7″ x 3.4″ x 1.1″70 hours
BEARTWO Portable Solar Charger10000mAh.46 lbs5.5″ x 3″ x 0.7″85 hours
Set of solar power banks and their capacity details

Buy FEELLE Solar Power Bank

Factors that are affecting to discharge of solar power banks efficiently

Battery Life: 

Every power bank would have a fixed life. The manufacturer generally mentions the average life of the power bank on the packaging. As the power bank gets old, the power generation capacity of the power bank gets reduced. 

The deep cycle battery needs more protection from overcharging. Overcharging of the batteries and frequent charges would also affect the battery life and cause damage to the battery.


High temperature accelerates the corrosion in the battery. As a consequence, the battery loses its essential function, and electrolyte loss could be seen. 

In contrast, the lower operating temperature boosts the battery life. Still, it is an inefficient way to charge the battery as it may take time to charge the battery to its total capacity. 

The power bank’s manufacturer can claim that the battery life decrease for every 10 degrees celsius increase in operating temperature. 

Self Discharge Rate: 

Based on the type of batteries, the batteries would have a self-discharge rate. The battery would undergo a reduction of the charging capacity. 

The higher the temperature around the battery, the faster the discharge can be experienced. The material used in the manufacturing of the batteries would also affect the discharge rate of the batteries.

How to choose a solar power bank last longer?

Buy a Portable Solar Charger, BEARTWO

The decision to buy the solar power bank could be made based on your requirement. Today, you can find solar power banks of different sizes and shapes. Each would be efficient enough to charge your electronic gadgets. Depending on your need, you can choose the solar power bank.

The higher capacity indicates the power bank would last for days in a single charge. You will be able to charge several electronics such as your mobile phones, radio, etc., without recharging them. 

Also, some high-end solar power bank comes with fast charging capacity so you can recharge the batteries quickly under direct sunlight.

You can buy a solar power bank rating from 2000 mAh to 30000 mAh. The more the capacity, the more power you get to store. 

If you are a frequent traveller and do not get time to recharge the batteries, it is recommended to go with the higher capacity. It will last longer and charge your Smartphone multiple times.

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