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July 21, 2017

How to Survive a Festival in 2017 - Festival Essentials

We all know that you need a tent and a ticket. We all know that you need food. There's no need to mention that. But what festival essentials do you need to survive a festival? In 2017?

Hand Sanitizer

This is the most important essential if you care about your health.

At a festival, you are exposed to all kinds of different people. Not all of them take care of their bodies.

Bathrooms aren't in the best condition either. Especially at big festivals. Water isn't available widely.

A hand sanitizer will clean your hands without you needing to use water. It's one of the absolute festival essentials.

Portable Charger

We send snaps on Snapchat. We take videos of artists. We capture great moments. But it’s 2017. Our phones are getting slimmer. They are also getting better. Better and slimmer probably means that your phone won’t last a full day.

Zendure A8 QC will charge your phone 7 to 9 times. In many cases, that should last you the whole weekend.

But perhaps you might not want to carry a portable charger with you at a festival. Festival clothing doesn't tend to have a lot of pockets. That's why the A8 QC is equipped with Qualcomm Quick Charge 3.0. With it, you will be able to charge your phone faster than ever before.

And festivals are social events. Your friends are going to be there with you. And that’s why the A8 QC has four USB ports, and that makes it one of the festival essentials and a must to survive a festival in 2017.

You will be using your devices. Stay with power.

A recent post about what you should look for when traveling abroad also mentions portable chargers.

Spare Cables

Your friends probably didn't bring any cables because they didn't know that you were going to have a charger unless they also read this post.

If you want to be considered a hero, bring some spare cables. It could bring you many benefits.

But cables tend to break. Somebody could stand on your cable. They sometimes just stop working. And a portable charger is of no use to you if you can't charge it. 

Zendure cables have been tested thousands of times to make sure that they last. And they come with an 18-month warranty.


Did you ever just meet someone but felt like you knew them forever? That sometimes happens.

Meet a girl. Meet a boy. Notice your similarities. Decide you like each other. Condoms are essential for your safety. It's simple. People know about them. They still forget them. If you are under the influence of alcohol, that can have long term problems.

Waterproof Backpack

You might not find a backpack useful as it will probably be in your tent at all times but it will keep useful items workin

You definitely don't want to see your electronics damaged because somebody spilled their drink on them. You definitely don't want to see a stain on your favorite jumper.

And that happens a lot. If you want to keep your belongings safe, get a waterproof backpack that will protect them. And if it's shockproof then that is even better.


While most of the festival community consists of people that are fun, there’s always someone that tries to ruin the fun when you are celebrating music. Make sure you have someone watching over your tent or some lock to protect your tent or the valuables inside of it.

Spare Clothes

We get it. You want to wear your fancy denim jacket for the next three days. But what if a drink is spilled on it when you are wearing it. What if ketchup falls on it.

Are you going to be wearing a dirty jacket? I wouldn't say so. Bring spare clothes because you never know what will happen.

Ear Plugs

Imagine you have a headache. All that music. Imagine trying to sleep with it. Ear plugs are one of those festival essentials that nobody ever brings. But yet a vital one.


A headache will be less likely to happen if you keep hydrated. So many people forget to do that. We remember about food, but we skip water. Dancing is also exercise. It dehydrates your body.

It's a good idea to bring your own water as water at festivals is expensive.  If you can, bring a little fridge too. So that you can keep your water cool.

Conclusion - Is That All of the Festival Essentials That You Need to Survive a Festival?

No. Everybody has their own needs. If you are planning to do a BBQ, you need to bring a grill. But these items are universal things that pretty much everyone will find useful.

These are not all of the festival essentials. But they will make your festival easier. If you want to survive a festival, make sure you have these.

Written by Michael Smolski

July 15, 2017

What Should You Check for When Traveling Abroad

Traveling has many great perks but it also has many little problems that can be very problematic if you are not aware of them.

People always mention the good about trips, but you cannot enjoy yourself if you don’t check for a few things when traveling abroad. And this post covers these.

Can You Drive?

Traveling is great. But is it really that great if you have no means of transport? Cabs can be expensive. Uber doesn’t work in every city. A train won’t get you to a precise location. A car? That might be a solution, but it depends on who you are.

When traveling abroad, one of the things you should really look out for is if you can drive because if you really want to go somewhere and don’t have a big budget, it will be hard to do so without a car.

In Europe, you can get away with having a European license. In the US, in certain states, you can get away with a license of your own country if you have an international driving permit.

This is all about safety. Ireland and the UK have a road facing in an opposite direction as an example. And drivers can struggle with that.

Bringing your car isn’t always an option. Long trips aren’t too comfortable, so your car might not always be the best choice.

So should you rent a car?

Perhaps, if you can.

You might be a great driver but if you are too young, then you won’t able to rent a car. In Poland, while the legal age is 18, you still have to be 21 to rent a car. And that comes with an extra fee for being young. Watch out for that.

Make sure your license will be valid in the country you are going to and that you can rent a car. Otherwise, you might have a big problem.

Socket Types

Arrive at your destination. Unpack. Take out your camera, phone, earphones, and your tablet. Realize that you cannot charge any of them because all of your plugs differ. What are you going to do now?

You need an adapter. Depending on your location, it might not be easy to get. And adapters are like chargers. A bad one will work but will eventually also break.

There are four different socket types in the world. If you are going from the US to Ireland followed by Germany, that’s three different sockets. That’s a lot of space and extra money.

They take up space. They aren't easy to find in shops. They often break because there are more amps coming in than the fuse can handle.

Zendure Passport adapter is like a passport. It works all around the world, and it has an auto-resetting fuse. But we are living in 2017. It’s not enough to have a socket. That’s why there are 4 USB ports present. To make sure that you can charge everything that you need to charge.

And if your device doesn’t have the greatest battery life but needs to last you a day while you travel, then use a portable charger. Zendure A8 QC will let you charge your phone 7 to 9 times. And it charges fast thanks to Qualcomm Quick Charge 3.0.

Fees and Whether Cards Are Accepted When Traveling Abroad

Not every country is pushing towards debit or credit cards. Certain places like to use the traditional method. And that’s why you should make sure to bring money with you.

Using cards abroad also brings fees. Banks need to make money, and one of the best ways to do it is by putting fees on people when they are traveling abroad. You need to be aware of that or the next time you try to pay then you might be out of funds.


Alcohol isn't legal to drink in public places in every country. Crossing the road isn't legal if there are no crossing paths in certain countries. You can get fined because of that in Poland. Some countries don’t allow alcohol at all.

And while certain countries might look similar at times, rules differ. When traveling abroad, you need to watch out. Especially in strict countries.


Transportation matters. You won’t get anywhere without it. Power is just as important in today’s era of electronics. Make sure you have an adapter that works everywhere and has everything that you need. Be aware of the fees. And most importantly, make sure you follow the rules.

Written by Michael Smolski

March 20, 2017

My Totally Unbiased Opinion on Durable Power Banks

Do you like to go camping in the spring, but you don't want to have to do without your electronics while you're roughing it? Zendure external batteries will be your new best friend.

They come in a tough and sleek ABS/Polycarbonate case, so you don't have to worry about damage while you rock climb, wrestle with bears, or go on long hikes in the wild. It's compatible with all your devices: phones, e-readers, your new Nintendo Switch that you can't put down. Essentially anything with a USB port. Zendure was developed by popular demand from a Kickstarter campaign and made to be just what people wanted in an external battery. Durability, sleek design, efficiency, and great value. Not all batteries are created equal. You don't have to sacrifice style to have a tough product, and we believe in listening to what people really want. That's why we have thousands of fans who stand by our products.

Sometimes you just absolutely need something that simply works, with no doubt in your mind. When you are expecting an important phone call, need to use GPS on your phone, are bored at the DMV and want to play games on your phone, the last thing you want to see is a red battery symbol on your screen. When you don't have access to an outlet, battery anxiety can ruin your day. Stop worrying about your devices being charged. Future camping you will thank you, and so will future airplane you, and road trip you. Never have to play the, "How long will my phone's battery last?" game again. Rest easy with Zendure.
December 01, 2013

The Ultimate Guide to Capacity (mAh,Wh) and Efficiency of Portable Chargers (a.k.a. Power Banks or External Batteries)

Portable chargers, a.k.a. power banks or external batteries have been in the market for years and have become a household item for almost every family. However, average consumers and even people in the industry are still confused about the basic concepts of this product, such as the capacity and efficiency. Some manufacturers use wrong or exaggerated data to mislead customers in their own interests. As the founder of Zendure, I'd like to clear up the doubts and misconceptions surrounding these very important factors.

Before we start, let's introduce some basic concepts.

Capacity: A battery's capacity is the amount of electric charge it can deliver at the rated voltage. The more electrode material contained in the cell the greater its capacity. A small cell has less capacity than a larger cell with the same chemistry, although they provide the same open-circuit voltage. Capacity is measured in amp-hours (aH). For power banks, milliampere hour (mAh, equals to one-thousandth of an ampere hour) is more commonly used.

Voltage, electric potential difference, electric pressure or electric tension (formally denoted ∆V or ∆U, but more often simply as V or U, for instance in the context of Ohm's or Kirchhoff's laws) is the difference in electric potential energy between two points per unit electric charge. The voltage between two points is equal to the work done per unit of charge against a static electric field to move the test charge between two points. This is measured in units of volts.

Current, measured in amperes or amps (A) is the rate of electric flow which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed one meter apart in vacuum, would produce between these conductors a force equal to 2×10−7 newton per meter of length.

Energy, measured in watt-hours (Wh) or joules (J), is a measure of the amount of work, or change, that can achieved. One watt-hour is equivalent to 3,600 joules. If the energy is being transmitted or used at a constant rate (power) over a period of time, the total energy in kilowatt-hours is the power in watts multiplied by the time in hours. The kilowatt-hour, equal to 1,000 watt-hours, is commonly used as a billing unit for energy delivered to consumers by electric utilities. For power banks, watt-hour (Wh) is more commonly used. 

Power vs. Energy: The terms "power" and "energy" are frequently confused. Power is the rate at which energy is generated or consumed and hence is measured in units (e.g. watts) that represent energy per unit time. For a power bank, the power is the maximum flow of energy that it can output, which equals to the voltage multiplied by the current. For instance, the power of a 10,000mAh power bank that can output 2.4A at 5V has a power of 12W. However, energy is the capacity times the voltage, so it's 10,000mAh*3.7V/1000=37Wh. 

During Zendure's Kickstarter campaign, we introduced a new term called Total Energy Conversion Rate (TECR). It means the total actual energy that a user can get from the power bank, divided by the rated energy capacity of it. This is the most accurate way to measure the efficiency of a power bank.

Now let's look at some of the common misconceptions. 

Misconception 1: Rated capacity is the actual capacity you will get

This is the most common misconception that a first-time power bank user has. A typical power bank consists of the following parts: internal battery cells, a PCB (printed circuit board) with voltage conversion and power management system, USB Ports, and the exterior shell. The rated capacity normally refers to that of the internal battery cells at the nominal voltage. For instance, if the power bank has two cells inside with each cell of a capacity of 3350mAh at 3.63V, it's rated capacity is 6700mAh at 3.63V. From here, there's still a long way to the actual total energy that can be delivered to your devices.

Misconception 2: Conversion Rate is the same as Efficiency

So the more educated consumers usually fall into this trap. A lot of power bank manufacturers educate consumers with this so called "conversion rate" concept. However, there are are lot of manipulations with this concept.

Manipulation type A: Some companies claim that their power banks have an conversion rate of over 90%, but what they won't tell you is that they're only referring to the efficiency of the PCB, not the whole unit. Internal resistance takes some of the energy out of the system. The batteries themselves usually hold a charge at about 3.7 volts, while the devices that they power require 5 volts. This transformation takes energy out of the system, as do other circuit operations. Manufacturers mislead customers by only providing a small piece of the total energy conversion picture.

Manipulation type B: This is actually a more misleading way and it's far harder to explain or expose. Some companies would print on their packaging the following numbers:

Rated Capacity: 16,000mAh 3.6V

Output Capacity: 10,200mAh 5.1V

Conversion Rate: 16000*3.6/10200*5.1>90% 

This is really misleading. Actually, 10200mAh refers to the capacity that it can charge the cell phone at, and the cell phone battery is normally 3.6V too, so, simple math here:

Total rated energy: 16000mAH * 3.6V = 57.6Wh

Energy Usable: 10200mAh * 3.6V = 36.72Wh

Actual TECR: 36.72Wh/57.6Wh=63.75%. 

How to calculate the actual capacity before you buy a power bank?

Congratulations. If you have read thus far, it means you have a basic understanding of what energy efficiency mean for power banks. However, this step is crucial for you to really understand the final answer.

As we know, Zendure A-Series batteries have an 80% TECR. This means, to approximate how many times a Zendure battery can charge your device, multiply the battery's capacity by 0.8, and then divide it by the capacity of your device. While this is true in most cases, you need to understand that this formula assumes that the device's nominal voltage is about 3.7V, is charged at 1A in a 25°C environment, and is powered off and not in use when being charged. Actual results may vary slightly depending on whether the device is in use, output used, temperature, how much heat the device's battery generates, the condition of the device, etc. So if you are using the power bank in a very cold place, charging the device at 2A, and if your phone also happens to be a very old phone with a worn-out battery, the TECR you might get would be much lower.

I hope that this has helped you gain a better understanding of the science behind power banks, so you can make an informed decision when choosing a product that will work best for you.