Does the iPhone 6 need a voltage converter

The right power supply for on the go

Patrick Woods

What you need to know about USB batteries, battery cases or solar chargers. Dozens of products tested and measured.

EnlargeWe have tested various battery cases, USB batteries and exotic ones.

What sounds so banal is actually a complicated matter: pumping electricity into the iPhone or iPad. Because the charging electronics of iOS devices are picky. Not every charger or every external battery is therefore ideal for Apple's mobile devices. We have therefore tried out and measured numerous concepts and variants in more detail. Which concept is best suited for which requirements and how much money should you spend once you have made a decision?

USB and chargers

A little excursion into the basics of physics. The voltage for USB is 5 volts (with minimal fluctuations). In theory, depending on the USB standard, the current strength is between 100 milliamps and one ampere, some chargers can deliver even more. The power results from the voltage multiplied by the current strength. In our example, this corresponds to between 0.5 and 5 watts of power. A practical example: The iPhone charger has an output of 5 watts (with one ampere), that of the iPad even 10 watts (with two amps). Important: the iPhone 6 and especially the iPhone 6 Plus can be charged with a higher power than the supplied power supply.

External battery packs

These are versatile power donors for on the go. These have one or more USB outputs and can thus supply almost everything with power that can be charged via USB - far away from any power socket. In addition to the versatility, the advantage is the large selection of battery capacities on the market. However, since the iPad has a very large internal battery, it must also be a very large external battery in order to regain energy for several hours of iPad entertainment. For the iPhone, however, a smaller battery is sufficient.

The batteries of the iPhones

Depending on the model, the iPhone has a battery with very different capacities. These are the data of the most important models:

Batteries are especially useful if you take a large, long-lasting variant. An inexpensive solution is sufficient for occasional trips and long journeys. However, the additional price for a better battery can be worthwhile. Because "better" batteries usually have longer-lasting battery cells, better features and can charge modern devices faster than cheap batteries. At the same time, large batteries have a disadvantage: even if they can partially charge the iPad quickly, they recharge their batteries more comfortably. It often takes many hours at the socket until an external battery is full again, because none of them support fast charging.

The batteries of the iPads

Fast loading

Background: The charge regulator in the iPad and iPhone determines the current intensity with which the battery is charged. Its task is to allow the battery to be charged gently and safely from the power source. This depends on the battery level, the current power consumption of the device and whether the charge controller and the charger "understand" each other. Because today's chargers and additional batteries almost always work outside of the USB specification. They can output higher charging currents and thus more power than USB originally intended. For this to work, the identification has to work. Only if the charging electronics in the iOS device also recognize that the electricity supplier can deliver more than defined in the standard will it allow faster charging. In practice, this means that many USB chargers and batteries only achieve a maximum output of 5 watts (1 ampere), although the iPad in particular supports charging with a higher output.

EnlargeThe charging process for the iPhone 6. The diagram shows the charging current over time. The charge regulator reduces the charging current - the fuller the battery is.

The fact that many batteries promise "up to 2.1 amps" or more output current according to the label hardly changes that. In many cases, the iPhone / iPad and battery cannot agree on this high charging current and therefore it is not or only partially used. The bottom line is that only higher quality batteries have sufficiently modern electronics so that the iPad fully supports fast charging. "Full" because there are often measurable differences between the "1A-" and "2A-" output of rechargeable batteries, but mostly very small. This is enough for iPhones up to 5S, however, it does not support higher currents anyway.

tip : The iPhone 6 supports more powerful charging than the included power supply unit (5 watts) can provide. Therefore it charges faster if you connect it to a modern, more powerful power supply - for example to that of the large iPad.

How much capacity do i need?

In the case of external batteries, the capacity is usually given and a vague description of how often you can charge "a smartphone" with it. If you know not only the capacity of the battery but also that of the device battery (see boxes above), you might think that you can determine the number of possible charges directly from this. However, this only works to a very limited extent. Because an iPhone battery with around 1500 mAh (iPhone 5 series) cannot be charged twice by an external battery with 3000 mAh. The reason is the moderate efficiency of the charging process, a lot of energy is lost in heat. Therefore, one can assume that a maximum of 80 percent of the energy from the battery can actually be used. The 3000 mAh battery charges the iPhone completely once and only half or two thirds the second time.

EnlargeWe wanted to know exactly and therefore measured the charging performance of a number of devices in conjunction with many different iPhones and iPads.

It's even more complicated with the iPad because it has a very large battery. IPad 3 and 4 in particular are real battery monsters, which therefore have to be charged for a long time and require an extremely large additional battery if they are to be fully recharged on the go. The majority of external batteries on the market with a typical 6000 mAh charge such an iPad only to a maximum of 40 percent and is therefore hardly worthwhile. Fortunately, the other iPad generations and models are a little less demanding.

Chargers for on the go

Normally, the original charger is also the best choice in a hotel or holiday apartment. In addition to the Apple power adapter, which charges the iPad faster than most third-party power adapters, there are also special travel power adapters that also do a good job. We tested the Digipower Dual USB power supply as an example. This has two USB outputs, has an output of up to 17 watts and costs around 25 euros. The highlight here is that the manufacturer has built in modern charging electronics so that new Apple devices also support fast charging here.

EnlargeCan be practical: a travel charger (here Digipower Dual USB) can replace several power supplies at the same time.

In the test, for example, the Digipower charges an iPad 3 a little faster than the original power supply. At the same time, a smartphone, for example, can still be charged with full power. This is not absolutely necessary, but can replace the individual power packs of the iPad and smartphone when traveling and quickly charge several devices at the same time. Intended for power users with many devices, or if you have lost the original power supply.

Electricity from the car

EnlargeOn the left a cheap power supply, in the middle a car charger with 12 watts for tablets (25 euros), on the right a smartphone supplier with 5 watts (10 euros).

Of course, the juice from the cigarette lighter is also part of the mobile power supply. Here, too, there are a number of variants that differ primarily in terms of performance. The cheapest 12-volt power supply units or the models that are included with some gadgets for free are not at all good for the iPad - and hardly for the iPhone either. Because these often only provide a maximum of 1.25 or 2.5 watts (250-500mA). This means that iOS devices do not charge at all, up to a maximum of very slowly. We recommend using only car power supply units with at least 5 watts of power, i.e. one ampere charging current. These are available from many manufacturers (often identical) and cost around 10 to 15 euros. This means that the iPad loads slowly at least. More power is even better, but these power supplies for the car are relatively rare and here again the question arises whether the iPad will accept this additional power at all.

Electricity from light

Solar chargers are becoming cheaper and cheaper and promise free energy away from the socket. That sounds like unlimited freedom and a self-sufficient power supply in the middle of the wilderness. In theory. Since solar chargers are still expensive and are therefore more of a niche product, we only tried one product from the category. The Sherpa 50 set from Goal Zero. This consists of a solar module and a large battery. The solar module has a maximum output of 13 watts, the battery is the buffer for solar power. It stores (converted to the iPad voltage) over 15 Ah. The Goalzero set is not a gadget, but a serious outdoor tool. Therefore, the battery pack (Sherpa 50) can not only output power via USB, but also has an output with 12 volts, a laptop output with 19 volts and, optionally, there is even a voltage converter that generates 230 volts. So you can even run a small laptop with it. This is reflected in the price. The solar panel costs 160 euros individually, the battery another 200 euros.

EnlargeGoalzero Sherpa 50: Versatile, high-quality and expensive, but a solar system makes only limited sense when you are out and about.

According to the manufacturer, the large battery should be full after around eight hours of sunbathing. In our practical experience, however, this cannot be achieved. Although we were lucky with the weather during testing, it takes two days instead of one to fully charge the battery. As soon as the solar device is not in direct sunlight, the charging time increases enormously. Then several days are necessary to even remotely fully charge the Sherpa. You only become self-sufficient if you don't have to permanently supply more devices than a smartphone or maybe two. To charge a small laptop or an iPad 3, you need all of the energy in the battery, which is then recharged after two days. If you take several battery packs with you on the camping weekend without electricity, this type of power supply is cheaper and more calculable than electricity from the sun.

Battery cases for the iPhone

Sunda_Extra_Strong The cheap home. The Sunda Extra Strong battery cover is a cheap China cover for around 11 euros plus shipping. Lightning without certification, somewhat sharp plastic edges and otherwise the last light in terms of processing. But it works and doubles the battery life for a fraction of the price of branded products.

© Macwelt to the picture gallery full view

iPhone cases with a built-in extra battery are great and terrifying at the same time. Because they have some advantages, but also serious disadvantages. One of the advantages is that the iPhone charges in your pocket and remains fully usable without the need for a cable or the inconvenient stowing of the iPhone in the backpack to connect it to a battery. The disadvantages, however, are that battery cases make the iPhone thick, are mostly expensive and can only fully charge the iPhone once, then your own battery is exhausted. In addition, the case will be completely useless with the next iPhone model because it no longer fits.

EnlargeThe cheapest case is poorly made and loads slowly, but is sufficient for casual users.

We tried battery cases (for the iPhone 5 / S) with prices between eleven and around 100 euros. From the cheapest Amazon offer to the high-quality Mophie cases. Our conclusion: even if the expensive cases are much better processed, the cheap case has the largest capacity in comparison and does what it should. It comes by post from China and is questionable with regard to the CE mark and does not have an original Lightning license, but otherwise there are hardly any differences to the mid-range battery cases, which cost 40 to 60 euros. However, it charges the iPhone rather slowly with only 500 mA. Such a cheap variant is sufficient for occasional use.