Solar battery for charging the phone – Solar Power Bank mobile chargers are in high demand today among smartphone owners. This is understandable – the very idea of charging gadgets from the sun is very interesting. However, there is one small “but”.
Space technologies, even in miniature sizes (solar battery for charging a phone), are expensive, so users choose cheap Chinese counterparts that can be bought on AliExpress for only a few tens of dollars.
On sale there are Solar Power Banks of different sizes and designs, while the most striking is the resource intensity of their built-in batteries, which ranges from 10,000 to 45,000 mAh.
But do these portable devices really live up to the manufacturer’s specifications?
How to check the real performance of a Chinese power bank?
Externally, the Power Bank with a solar battery unambiguously inspires confidence – the device has a rather complex design, which consists of monocrystalline photo panels that “absorb” the energy of the sun, and electronics hidden under a durable plastic and metal case.
The standard package includes several connectors: two USB ports (for charging smartphones) and one mini USB for charging the power bank from the mains.
The Power Bank is also equipped with LED indicators that indicate the level of the battery being charged, and a simple LED flashlight for backlighting.
Now let’s move on to the main question: how can you check the real indicators of solar charging of a mobile phone at home and compare them with the factory specifications? First, you need to open the device case – depending on the design of the power bank, you need to unscrew 6-8 screws or just open the plastic latches.
1) Checking the solar cell
You can measure the voltage of the photovoltaic panel using a standard voltmeter or multimeter. Usually this figure is kept at 5 V, but note that the voltage can “jump”, depending on the position of the photocells relative to the sun’s rays.
For the most accurate verification, it is recommended to place the Power Bank at right angles to the sun.
The original models sometimes show solar batteries for charging at 6-7 V, which is definitely good. While some Chinese power banks are very often unable to generate even 70% of the manufacturer’s declared power of a photovoltaic module.
In this case, it is better to return the mobile charger – there will be little benefit from it, since the batteries will be charged from the sun for several months.
Please note that in diffused light or bright artificial lighting, the photovoltaic cells will not charge the battery, and even if the green charge indicator is on, this only indicates that the photovoltaic module works as a light sensor. The built-in rechargeable battery requires only solar radiation to fully recharge.
2) Checking the battery capacity
Most of all, users are interested in the real capacity of the battery, because it depends on how many gadgets can be recharged at 100% charge of the power bank. There are two ways to measure the resource intensity of a lithium-ion battery or a lithium-polymer battery.
The easiest, but far from the best, method is to check the charging capacity of solar panels based on the actual number of full charge cycles of the smartphone. If you have a smartphone with a 2000 mAh battery, then you will need to calculate the total number of complete charging cycles of a mobile phone from a portable power source. For example, if it was possible to fully charge the smartphone only two times, and the third time the recharging “stuck” at the level of 75%, then you can determine the real battery capacity of the power bank using the formula:
(2 * 2000) + (0.75 * 2000) = 5500 mAh.
In doing so, do not forget to take into account the loss factor in the process of converting solar energy. The default is 1.3.
5500 * 1.3 = 7150 mAh.
In this case, the real capacity of the power bank’s battery is about 7000 mAh. As practice shows, the real capacity of Chinese portable power supplies is usually 2-3 times less.
There is also a more accurate way to check the battery charging capacity for a phone from a solar battery, but for this you will have to additionally purchase a special USB-Tester, which is able to measure the main characteristics of the battery, as well as current and voltage indicators.
Be sure to discharge the device before starting the test.
How can you modify a power bank with a solar battery?
Upgrading Power Bank is a delicate matter, and only radio amateurs and “techies” are engaged in this. It would be inappropriate to give any specific advice in this case, since each user has his own needs and preferences.
Adding new lithium-ion batteries in order to increase capacity must be extremely careful, since the built-in balancer (charge controller) simply cannot cope with the load.
If you add new batteries in parallel and bypassing the balancer, the device will work, but until the first battery explosion.
Advanced owners of Power Banks operating on lithium-ion and lithium-polymer rechargeable batteries recommend making a remote solar panel, because in Chinese models, “artisanal” batteries often overheat when they lie in the sun for a long time. This will damage the lithium-ion batteries.
Why buy Chinese Solar Power Banks at all?
Portable food sources are useful, especially if you are going on a barbecue or camping trip. Despite the fact that Chinese chargers that are sold in Moscow are most often found defective, the demand for them is still growing. And it is the low cost that attracts.
Why pay more money for a brand when you can buy a fake and modify it? At the same time, you do not have to additionally tinker the case – everything is already ready and looks very presentable.
Also, portable chargers are often bought for home experiments. And in this case, the Chinese counterparts are considered the best option.
There is no need to solder the microcircuit “from scratch” – even cheap boards have built-in protection against overcharging, over discharging and short circuits, as well as a solar energy-to-electric current converter. Therefore, the Chinese solar phone charger allows you to experiment without compromising your home budget.
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