3 Game Changing Solutions to Recharge Your Smartphone without an Electric Outlet

When was the last time you went out without your smartphone? If you are like me, the answer is: never. But, now if I ask you when was the last time you checked the battery level of your device, the answer is likely less than a couple of hours. Although the new batteries are better than what we had few years ago, our devices became thiner. Energy storage capacity is hence constrained. To add insult to injury, we witness increased computing capabilities of our gadgets. Now we have multicore chips in our handheld and wearable electronics, with high resolution screens. They require an important amount of electricity. The low-energy labels, should be understood as relative to former technology. Watching a video or playing a game still drain the battery. But, the electronics became smarter. The components shut down and hence save energy, each time they aren’t used. Even for short periods of time, this contributes to save few battery percents. It’s better than nothing, although it does not fully address the problem of limited battery capacity. We still need to recharge too frequently.

One trivial solution is to get a secondary battery (so called energy bank). This solution at least doubles the time you run on battery. Typically, When on the street and the phone’s battery reaches the 5% limit, just plug the energy bank and your gone for an extra 24 hours. That’s more than enough to a place with an electric outlet.

Secondary batteries only save you some time before the next recharge. Ideally, you should never plug your devices to the wall anymore! In the following we introduce 3 game changing solutions that pave the way towards this ideal. What’s more they are eco-friendly. They rely on 3 different sources of renewable energy and hence contribute to fight climate change.

Wearable Motion-Based Charger: Exercise & Charge

The promise of AMPY MOVE is to transform the kinetic energy from your motion into battery power. This portable battery needs to be carried typically attached to your arm or leg, or in a backpack. Then, it automatically charges as you move. The more you move, the more power you get. An optional free companion app allows to analyse the amount of energy you have generated.

AMPY MOVE is about the size of a deck of cards and about the weight of a smartphone. It captures the energy from walking, running, cycling, and other human motion. For the lazy, don’t expect to recharge it while driving. The vibrations from a moving car are typically too weak to charge AMPY. However, you can charge it from the wall, on days you don’t exercise.

Once fully charged, the embedded 1800 mAh battery delivers up to 24 hours of extra smartphone battery life. Thanks to the USB and micro-usb connectors, you can charge all kinds of devices.

According to AMPY’s official description, 1 hour of exercise can produce up to 1 hour of smartphone battery life for normal use, or 24 hours of smartwatch for normal use too. However, walking doesn’t generate that much energy. You need to go for a run or bike to get the most motion power into AMPY. Unfortunately, this promise seems to be far from reality. Customer comments on Amazon are mostly negative. The average score is only 2 stars for 34 reviews. The main criticism is that the AMPY does not charge, even after intense exercise. The answer is that you should ensure that the battery has some charge prior to exercising. It seems that you need to plug AMPY to the wall or shake it for about 30 seconds. This is weird. But, the idea of generating electricity from motion is compelling. Hopefully we’ll eventually get a reliable working product.


Photosynthesis-Based Charger: Welcome to the Future

As crazy at it might sound, BIOO is a USB charger that relies on plants photosynthesis to produce electricity. This plant pot has two parts. The upper parts contains soil and a plant. The lower part contains some micro-organisms that are involved in a chemical reaction that produces electricity. To enable this reaction, the bacteria rely on some organic substances that are generated by the plant’s roots from photosynthesis. The organic substances are drained downward with water, to the compartment with micro-organisms, that decompose them, generating the electrons that will recharge your smartphone (see Video below).

BIOO is currently under development. The Spanish team plans to make a pot that is 25cm height (less than 10 inches). It should allow to charge 2 phones for approximatively a full day. Since the micro-organisms are active all the time, you can charge your USB devices day and night.

Solar Chargers: The Paradox of Choice

Using solar panels to produce electricity is not new by itself. However, we find nowadays plenty of solar chargers, in all sizes and colors. The choice isn’t obvious, since not all items found on the market are effective, as revealed by our analysis.

A solar charge has at least 2 parts: the photovoltaic panels, and a battery pack. When exposed to sun, the panels generate electricity that charges the battery pack. Larger batter packs, provides you with electricity for longer period of time. But, this comes at the expense of weight. Ones that provide about 2000 mAh seem like a good trade-off.

Regarding photovoltaic panels, the larger they are, the better. Larger ones allow faster charge, and produce electricity even under cloudy skies. So, for a true solar charger, ignore ones with small panels. They only allow topping off the unit. A better choice is to take a charger with a foldable panel, or one embedded in a backpack.

It is worth mentioning that sometimes the solar panels are sold alone. That’s the case of the foldable panels made by Anker. You can directly plug them to your smartphone to charge it. However, we recommend you to have a power bank along the solar panels. So, if your phone’s battery is already full, you can store extra energy that you’ll use during the night.


Although good solar panels allow charging a smartphone, the current state of the technology requires several hours in a perfect sunny day to fully charge your smartphone. A very interesting ongoing project to tackle this limitation is rawlemon. It successfully raised $233,062 in an Indiegogo campaign. Although the project didn’t deliver yet, raising a lot of criticism, the team is still active as shown in the video below. It presents a small prototype that is supposed to charge a smartphone in 4 hours. What’s impressive about the project is that it requires only very small photovoltaic panels (only a square 5mm in the video!). The secret? A spherical lens that concentrates the sun light. Welcome to the future!

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