The PRUFEN USB charging cable became my second most important travelling tool. It is very much versatile, like a Swiss pocket knife for smartphones. I have it since 2017 and I cannot live without it any more.

You can order it here http://prufen.com/ for US$ 19.90.

And here is where I am coming from:

My most Important Travelling Tool is my Smartphone

It goes without saying that my smartphone became my most important gadget for travelling. Not only that I can do my entire professional communication with it, so that I don’t even need a laptop any more. It has a built-in camera, I have access to all my cloud data files, it is my travel clock, my navigation system, my notebook, my translator, my e-book reader, etc. etc.

However, the big problem with smartphones is that they have limited batteries.

How I am Keeping my Smartphone Fully Charged when Travelling

The right charging of my smartphone is crucial. Charging must be quick, and I usually charge my smartphone whenever I am near a 110/240V wall socket or if I am in a car.

Four components are needed for proper charging at any location while travelling:

• a low-loss USB cable,
• a high-power charger,
• a country adapter for the local wall socket, and
• a 12V cigarette lighter charger for easy charging in a car.

I usually carry all four (4) components on me, and the cable is a PRUFEN USB charger cable, with iPhone adapter. From here http://prufen.com/

How to NOT charge your Smartphone When Travelling

When travelling, I usually do not use someone else´s charging cable/charger combination for charging my smartphone, for various reasons.

First, I have no protection against over-voltages. Second, the charging currents often are very low. A normal charging current is 1.7 Amps, but some chargers provide only 0.5 Amps, which means that I get only 30% of the potentially possible charging speed. That makes a huge difference, as this triples a full charging time of only two (2) hours to a total of more than six (6) hours. Only in the first case is my smartphone fully charged over lunchtime.

Second, if you accept an existing charging cable/charger combination, you give the life of your smartphone (and your own life until you are back home) fully into the hands of the friendly but often ignorant person who is offering the free charging. Moreover, many times I found out only after the charging, that the charger did not work at all. So I left the place after one hour with a smartphone that was even emptier than before the charging.

The Right Charging Strategy, not only when Travelling

This is where the PRUFEN USB charging cable comes in. It is actually a low-loss USB charging cable with a built-in multi-purpose measurement instrument.

“Low-loss” means that the PRUFEN USB internal power cables have an extra-large diameter, so that the cable resistance is lower than 0.05 Ohms. Please note that thin USB charging cables can have an internal resistance of up to 0.5 Ohms. That means that there will be a charging voltage loss of 1 V (= 20% of the 5 V charging voltage) if the charging current is 2 Amps. A bad charging cable will therefore cause a long delay in charging and prevent the smartphone from being fully charged.

The built-in multi-purpose measurement instrument in the PRUFEN USB charging cable helps me to find out whether the phone is actually charging at all, and how fast the phone is charging. In case that there is an over-voltage or a high temperature at the electrical connectors, the PRUFEN cable will interrupt the charging and complain with a loud beeping sound that cannot be overheard.

The PRUFEN USB Travelling Charging Strategies

The PRUFEN USB cable features open a wide range of charging strategies when I am on the go.

What I usually do is to sit down in a café or restaurant, plug in my PRUFEN charging cable into my smartphone and ask the waiter whether I can connect the other end of my charging cable with his USB charger. Which is what he usually will do. If the PRUFEN cable does not complain with a loud beeping sound I then check out the charging current, and if the charging current is high enough – let’s say higher than 1 Amp – then I let it sit charging.

Only if the charging current is lower than 0.7 Amps will I take out my own charger. This is more complicated because then I have a problem to also provide the right country adapter for my charger. Usually I have the right country adapter with me, but then we need to unplug the existing charger and to plug in my charger, which waiters are usually reluctant to do, depending on their agreeableness and openness character traits, and depending on how busy they are.

That is how I charge my smartphone when travelling.

When the PRUFEN USB charger cable does NOT work

Plugging in my own charging gear is often a problem because wall sockets are often hidden somewhere in another room to which I do not easily get access. So this often does not work.

Some social skills are needed to overcome this problem, which is often the bigger problem for us engineers. This problem cannot be solved by purchasing something online.

The other Features of My PRUFEN USB Charging Cable

The PRUFEN USB cable multi-purpose instrument comes with a charge energy amount counter mode which helps to determine a damage of the smartphone battery. This usually results in a loss of electrical storage capacity. Other information are the temperatures of the two electrical connectors, and the voltage of the power supply and the charging voltage of the phone (both compensated for the cable losses!).

Some other useful information about the PRUFEN USB cable

I personally know the developer of the PRUFEN USB cable. He is a retired semiconductor R&D engineer in Singapore who worked for MNCs such as Fairchild/National Semiconductors, and Phillips. He developed the 7414 Schmitt-Trigger Inverter IC, and trouble-shooted a lot of other ICs during his active career. His cousin in China helped him to manufacture the first two series of PRUFEN USB cables.

How about Discounts

Don’t fall for cheaper copies of the same device, on Amazon or on Lazada (for example here). These knock-offs come without all the above mentioned safety features of the PRUFEN USB cable, and they provide you only with raw measurements.

Call to Action

Proceed to this web page http://prufen.com/

Then order one cable for yourself and another one for one of your good friends. Don’t forget to order an iPhone adapter, if needed.

Please note that only very few people would appreciate the PRUFEN USB cable. Most people don’t mind whether or not they are properly charging their smartphones. That is the difference between men and boys.

Martin “Optimize Smartphone Charging” Schweiger