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Travel and USB Electronics

Universal Serial Bus (USB) electronics have changed how we travel.  These devices are small, lightweight, and work internationally.  This is why traveling with USB is one of the Five Key Principles of Light Travel.  An increasing number of electronics charge and communicate via USB, making it even easier to take electronics on the road.  Unfortunately, many people don’t fully understand how USB really works.  Since they don’t understand USB they are travelling with more equipment (and more weight) than needed.  Today we’ll look at how the majority of USB powered devices work and show you how to travel lighter with them.

Many electronic devices have a USB charge option

When most people think USB they think of smart phones, MP3 players, battery packs, and GPS devices.  But wait, there’s more!  Manufacturers have expanded the choices to include personal computers, headlamps, batteries, mobile Wi-Fi (MiFi), and portable shavers.  Almost any low power device is now available with a USB charge option.  Consider looking for a smaller and lighter USB version of your electronics the next time you shop for a new or replacement item.

Some of the many electronics powerd by USB.

These are just some of the devices powered by USB. From top to bottom, left to right: Tablet PC, MiFi (personal wireless device), smart phone, steri-pen, headlamp, solar charger and battery backup, power port battery charger.

Petzl Tikka with optional USB powered battery pack.

My Petzl headlamp accepts a battery insert that recharges via micro-USB. I get several hours of very bright light using this system. It usually takes around 4 hours to fully charge a drained battery pack. If needed, I can pop the insert out of my headlamp and use AAA batteries as a power source. I have many ways to recharge my headlamp so I never have to worry about running out of battery power while on travel.

All USB chargers convert incoming voltage to 5 volts direct current (DC)

All USB chargers are known as “step-down” converters and drop the output voltage to 5 volts – regardless of the input voltage.  So why do you really care about this?  It means that the charger will convert any standard input voltage to the correct output voltage.  You can use a USB charger on all continents without using a voltage converter.  All you need is a country specific adapter plug.  You can also use the 12 volt power port in your automobile.  Your USB power device is happy and fine with it.

Most USB chargers are dual voltage making them appropriate for minimalist travel

The specification for this dual port USB charger shows that it takes 100-240 volts, 50-60 Hz. This means it works for international travel with only a country-specific adapter plug. There is no need for an electrical converter. The charger converts the output to 5 volts DC.

USB electronics have multiple charging options

USB devices are low power direct current (DC) devices.  This means that they have many charging options that are not available for higher power alternating current (AC) devices.  USB devices charge through solar cells, USB auto power plugs, USB wall chargers, computer USB ports, and hand crank batteries.  The odds are that you will find at least one of these options available during your travel.  The solar charging and hand crank options also make USB devices great for emergency situations. It may take a while to charge the device, but at least you will eventually charge it!

Charging options for USB devices

Many charging options are available for USB devices. From left to right, top to bottom: A solar charger, a multi-plug power strip, a laptop USB port, a USB wall charger, and a USB auto charger

Most newer USB devices – except for Apple – use micro-USB connectors

Apple micro-USB to Lightning adapter

Apple has created a micro-USB to Lightning adapter that complies with the international micro-USB standard.

Several manufacturers met in 2007 to standardize mobile phones.  This means that most phones manufactured after 2007 use micro-USB connector/synch cords.  Other electronics groups started using this standard too.  The only major exception is Apple, which uses the Lightning protocol.  Why do you care?  It means that all of your non-Apple devices can share the same connector cord.  Rumor has it that Apple will be forced to use to the new standard by 2017.  Apple does provide a micro-USB to Lightning adapter if you only want to use a micro-USB connector cord.  I have had mixed success using the adapter.  I have never had problems charging my iPhone but have had multiple problems synching with iTunes.  I finally gave up and decided to carry an extra Lightning connector cord when I travel.  That means I bring 2 cords – an Apple connector for my iPhone and a micro-USB connector for everything else.

USB devices come in 0.5 Amp, 1 Amp, and 2 Amp versions

Most of the older (pre 2007) and smaller USB devices take 0.5 A as the input current.  Smart phones take 1 A as the input current.  Larger devices, such as Kindle, iPad, PCs, and tablets need a 1.8 – 2 A input current.  This means that you can’t use a 1 A smart phone charger to charge your 2 A iPad as it doesn’t have enough current.  But here’s something you should know –  the same 2007 standards that directed that USB devices use micro-USB connectors also directed that USB electronics automatically limit current so they won’t blow up. That means  you can use your 2 A iPad/Kindle charger to charge your 1 A smart phone.  That’s right – a single 2 A charger will charge all your devices!  If you want to charge two devices at once then buy a 2 port USB charger that outputs 1 A on one port and 2.1 A on the other port.  This will take care of all your charging needs.

Warning #1 – some multi-port USB chargers list their amperage as a combined amperage.  The spec will say something like “2.1 A combined”.  This means that the total output is 2.1 A.  If you plug a 2 A device into one port then there is nothing left over for the other port.  If you want a true dual port charger that charges two devices at once it will have a 3 A total rating. (1 A + 2 A).  Read the specification before you buy!

Warning #2 – Older automobile power ports are not equipped for the higher current dual port chargers, although true cigarette lighters do have enough current.  You will blow the auto’s fuse if you try to charge a 1 A device and a 2 A device at the same time in a low power port (you’ll know when it goes dead).  Keep your charge current below 2 A  in an older auto (one iPad or 2 smartphones).  Even some newer autos only output 1 A, which isn’t enough for a tablet device.  It will charge very slowly, if at all.  Autos are slowly switching to higher power outputs but it is a bit of a gamble, especially with rental cars.

I always take a dual port auto charger and a dual port wall charger with me when I travel.  The 2.1 A side is needed by high power USB devices such as iPads, Kindles, and table/PCs.  Other devices may use both sides of the chargers.  Devices manufactured after 2007 limit the current if they are plugged into a higher current side.

I always take a dual port auto charger and a dual port wall charger with me when I travel. High power USB devices such as iPads, Kindles, and table/PCs need the 2.1 A side. Other devices may use both sides of the chargers. Devices manufactured after 2007 limit the current when plugged into a higher current side.

My Personal Solution

I travel with an iPhone and several standard USB devices.  Sometimes my travel companions use a higher power iPad.  My solution is to bring a dual port USB wall charger.  One side charges at 1 A, and the other side charges at 2.1 A.  That means that I can accommodate any type of USB electronics.  I have a dual port auto charger configured the same way.  I can charge two items at the same time using the wall plug – I just need two connector cords.

Because I have an Apple device, I bring two different types of connector cords. One cord is a micro-USB cord and the other is an Apple Lightning cord. My Lightning cord is 4 feet long (1.2 m). The longer cord lets me use my smart phone while it is charging. It also reaches the auto power port when I have my phone mounted on the car as a GPS device.  If I did not own any Apple products I would bring two micro-USB connectors.

I bring a USB powered head lamp and a USB powered battery charger in addition to my synch cords, auto, and wall chargers.  My electronics fit into a small zip-loc.

Lady Light Travel personal electronics cords.

These are all the cords and electronics I take with me, with the exception of my smart phone, door alarm, and hair tool. From top to bottom, left to right: Micro-USB synch cord, headlamp with USB insert, power port USB battery charger, dual USB wall charger, dual USB auto charger, Lightning USB synch cord (for Apple devices). The micro-USB cord works for all of my non-Apple USB devices. The 2.1 A side of the chargers powers all devices, while the 1 A side of the dual port chargers powers all devices but PCs, Kindles, and iPads.

Travel lighter – dump the chargers!

Take some time to go through your travel electronics. See if you can combine chargers and cords. Consider ordering a multi-port USB plug so you can combine chargers even more. Dual port chargers eliminate fights over the wall plug/auto power port. They are also great when all the wall plugs are in use.  You can almost always negotiate sharing the plug with another user if you have a dual port plug.  That feature alone is worth the investment!

Updated on July 7 2014 – Added warning about dual port USB chargers in response to a question from Facebook.