The latest information on portable batteries, now essential for hikers
In recent years, the use of digital devices outdoors has become so commonplace that it's hard to find anyone who doesn't have one. High-tech devices such as smartphones, smartwatches, GPS devices, rechargeable headlamps, and digital cameras have (for better or worse) enabled us to live more comfortably and safely in the harsh and dangerous outdoors than ever before
The more electronic devices you have, the more of a problem battery life becomes. If you're hiking for more than one night, you'll inevitably run out of power after the second day, so it's essential to have spare batteries on hand. In the past, people simply prepared spare batteries for each device, but nowadays, most gadgets are rechargeable with the same USB port, so carrying a mobile battery is a smart choice. With just one of these handy charging devices, which can now be found at any convenience store, you can usually charge all of the electronic devices mentioned above
However, there are a wide variety of mobile batteries on the market, ranging from low-quality to high-performance models, and in terms of performance, capacity, and features, there is a wide range of quality to choose from. Of course, when choosing a model that can be used properly in the special environment of the outdoors, not just any model will do. To avoid regretting your purchase, you need to keep a few points in mind
So, this time, from the new models of mobile batteries that appear every year, I actually purchased some that I thought were the best, using my own money, and tried them out for hard activities like mountain climbing. I will introduce the models that I truly recommend and found to be convenient and safe to use, and in the second half I will explain the points you should check when choosing the best mobile battery
table of contents
- [By category] Recommended mobile batteries for mountain climbing this season
- Recommendation 1: ELECOM NESTOUT DE-NEST-10000BE
- Recommendation 2: Goal Zero Venture 35 Power Bank
- Recommendation 3: Tama Electronics Coleman CLM-TLP122UCAZ
- Recommendation 4 (Bonus Value Category): Powerness U36 Mobile Battery
- [Reference] Specifications of the outdoor mobile battery candidates tested this time
- How to Choose: 6 Points to Choose a Smart Mobile Battery for Outdoor Use
- Point 1: Battery capacity: We recommend a model with a capacity of around 10,000 mAh
- Point 2: Charging speed (output/input) – The USB PD (USB Power Delivery) standard is essential
- Point 3: Waterproof, dustproof, shockproof, and temperature range compatible
- Point 4: Weight and size
- Point 5: Types and number of interfaces
- summary
[By category] Recommended mobile batteries for mountain climbing this season
Recommendation 1: ELECOM NESTOUT DE-NEST-10000BE
Favorite points
- Lightweight and compact
- Fast charging for your devices with USB Power Delivery
- Fast charging of the battery itself
- IP67 waterproof and dustproof, and excellent impact resistance
Close call
- For better or worse, there are no extra features
- Few terminals (USB A x 1, USB C x 1)
Recommendation 2: Goal Zero Venture 35 Power Bank
Favorite points
- IP67 waterproof and dustproof, and excellent impact resistance
- compact
- Fast charging for your devices with USB Power Delivery
- Fast charging of the battery itself
- Abundant terminals with USB C x 1 and USB A x 2
- With LED light
Close call
- Slightly heavy
- Slightly expensive
Recommendation 3: Tama Electronics Coleman CLM-TLP122UCAZ
Favorite points
- Thin, lightweight and compact
- Fast charging for your devices with USB Power Delivery
- IP67 waterproof and dustproof (fairly shock-resistant)
- Includes carabiner and carabiner hole
- With LED light
Close call
- Few terminals (USB A x 1, USB C x 1)
- The temperature range is slightly narrow (5℃～35℃）
Recommendation 4 (Bonus Value Category): Powerness U36 Mobile Battery
Favorite points
- Amazing cost performance
- Lightweight and compact
- Fast charging for your devices with USB Power Delivery
- IP67 waterproof and dustproof, and excellent impact resistance
- Includes carabiner and carabiner hole
- LED lantern included
Close call
- Customer support is a bit questionable
- Few terminals (USB A x 1, USB C x 1)
[Reference] Specifications of the outdoor mobile battery candidates tested this time
| kinds | ANKER PowerCore Solar 10000 | BUFFALO BMPB10000WPBK | Goal Zero Venture 35 Power Bank | INOVA 3R-BTC04BK | LUMENA LUMENA II | ELECOM NESTOUT DE-NEST-10000BE | Powerness U36 Mobile Battery | Tama Electronics Industry Coleman CLM-TLP122UCAZ |
|---|---|---|---|---|---|---|---|---|
| image |  |
 |
 |
 |
 |
 |
 |
 |
| Size (mm) | 164×78×20 | 121×68×27 | 112×68×28 | 166×82×20.5 | 129×75×22.7 | 126×61×36 | 97×97×28 | 142×72×18 |
| Weight (g) | 267 | 272 | 286.9 | 375 | Approximately 280 | 241 | 275 | 253 |
| output |
|
|
|
|
|
|
|
|
| input | DC5.0V/2.1A | DC5.0V/2.0A | Max 18W, 5-12V Max 3A | DC5V/2A (microUSB) | 5V/2.4A | 5V/3A, 9V/2A maximum 18W |
PD18W (5V/3A, 9V/2A, 12V/1.5A) | 5V/3A, 9V/2A maximum 18W |
| USB PD | ◯ | ◯ | ◯ | ◯ | ||||
| Specifications Capacity (mAh) | 10,000 | 10,050 | 9,600 | 16,000 | 10,000 | 10,000 | 10,050 | 10,000 |
| Charging time (approximate) | Approximately 5.5 hours | Approximately 6.9 hours | Approximately 3 hours | 10 hours *When using a DC5V/2A AC adapter (sold separately) | 5 hours * 5V/2.4A | 2 hours 45 minutes *When using a USB PD 18W or higher AC charger | Approximately 3 hours (when using an AC charger with Type-C PD function and an output of DC9V/2A) | The shortest time is about 4 hours |
| Operating temperature range (approx.) | 0℃～55℃ | 10℃～40℃ | 0～45℃ | ？ | 0℃～40℃ | 0～40℃ | -10～60℃ | 5℃～35℃ |
| Interface |
|
|
|
|
|
|
|
|
| Waterproof/dustproof function | IP64 | IP65 | IP67 | IP67 | IP67 | IP67 | IP67 | IP67 |
| Shock resistance | US MIL Standard | ◯ | △ | △ | ◯ | ◯ | △ | |
| Solar charging | ◯ | ◯ | ||||||
| Light Lantern | ◯ | ◯ | ◯ | ◯ | ◯ | ◯ | ◯ | |
| accessories |
|
|
|
|
|
|
|
|
How to Choose: 6 Points to Choose a Smart Mobile Battery for Outdoor Use
Point 1: Battery capacity: We recommend a model with a capacity of around 10,000 mAh
The first thing you need to decide when preparing a mobile battery is how much battery capacity you should bring
Battery capacity generally refers to the total amount of electrical energy that the battery can store, and is expressed in units of milliampere hours
This number is like the size of a car's fuel tank, and naturally the higher the number, the more power it has (= the longer it can run) and the more power-hungry devices it can fully charge. However, it's not always the case that just because the capacity is large, it tends to be physically heavier and larger, and also more expensive, so you need to consider the balance when making your decision
Now that you understand the concept of battery capacity, we will explain how to determine the optimal capacity size
To get straight to the point, as of 2022, we recommend a model with a catalog-listed battery capacity of around 10,000 mAh . Anything more than that is a bit too heavy. If you're on a short trip of up to one night and just need your smartphone to last, or if you're carrying it as a backup (prioritizing portability as much as possible), then a 5,000 mAh model may be sufficient. Incidentally, for longer trips of more than three nights, relying solely on a mobile battery will require a larger, heavier model with a higher capacity, and in that case we recommend using it in conjunction with a solar charger or similar.
To find out how much battery capacity you need, first measure the total battery capacity of the devices you will be carrying
The battery capacity you need for your mountain trip simply depends on the total battery capacity of the devices you will be carrying
For example, the battery capacity of the iPhone 6 used to be around 1,800 mAh. Today, the iPhone 14 Pro Max has more than double that, at over 4,000 mAh. The Android smartphone Pixel 6 Pro has a whopping 5,000 mAh. The GoPro HERO11 Black, a popular action camera model, has a battery capacity of 1,720 mAh. The Insta360 X3, a 360° camera, has a 1,800 mAh battery. The original battery for the Sony α7 III mirrorless digital camera is 2,280 mAh. As you can see, to fully charge a single electronic device today, you need a minimum of around 2,000 mAh, and as much as 5,000 mAh.
It's no longer the case that you could just think about charging your smartphone, as in the past. Now that we carry around many electronic devices, including smartphones, digital cameras, smartwatches, and headlamps, it's natural that you need a capacity that can cover them all
By the way, here is a list of all the devices that I take with me on overnight mountain hikes that need to be charged
- Smartphone "Google Pixel 6 Pro" ... 5,000 mAh
- Smartwatch "Garmin fēnix 6X Pro" - Less than 500 mAh (estimated)
- Black Diamond Revolt 350 headlamp: 1,800 mAh
- Camera "SONY α7 III" ... 2,280 mAh
- GoPro and other video cameras "insta360 X3"...1,800 mAh
Just to give you a rough idea, there are a lot of electronic devices that need charging. The total comes to a whopping 11,383 mAh! Of course, not all of these devices need to be charged to 100% every day, so even if you take that into account, 5,000 mAh is still not enough..
Therefore, it is important to note that a mobile battery with a capacity of 10,000 Ah does not necessarily mean it is safe
Don't be fooled by specs: How to calculate your battery's actual capacity and how much capacity you need
For example, with mobile batteries, a mistake to assume that a mobile battery with a specified capacity of 2,000 mAh can charge a 1,000 mAh device twice (in reality, it is not enough).
In fact, a 2,000 mAh mobile battery can charge a 1,000 mAh device up to 1.4 times, although this varies slightly depending on the manufacturer and product. The reason for this is due to the following two factors:
- Decrease in output capacitance due to boosting
- Power consumption of the mobile battery itself
To explain as thoroughly as I can, the output voltage of the lithium-ion battery (battery cell) in a mobile battery is 3.7V. By contrast, the voltage of a USB port is 5.0V. When charging a device, this 3.7V must be converted to 5.0V, a process known as "boosting" from 3.7V to 5.0V. According to the formula "3.7 / 5.0 = 0.74," the capacity at 3.7V output is reduced to 74% at 5.0V output. In other words, the first reality is that no matter how hard you try, a mobile battery can only theoretically charge 74% of its specified capacity
Another thing to note is that some power is lost during this voltage conversion. Various other types of power are also required for the mobile battery to function properly. The power consumed by the mobile battery itself also contributes to its overall capacity. When all these factors are taken into account, the actual charging capacity of a mobile battery is actually only 60-70% of its rated value .
What's surprising is that manufacturers don't properly explain this reality at all. Some conscientious manufacturers will casually include the actual number of charges possible when claiming that a product can "charge a smartphone XX times" (even then, many of them don't include the battery capacity of the reference smartphone), but some of the worst manufacturers simply divide the theoretical value from the specifications to provide the number of charges possible (for example, a 10,000 mAh battery can charge an iPhone 11, which has approximately 3,000 mAh, 3.3 times). In any case, users must be mindful of this inconvenient truth
How to calculate the optimal capacity for you
For these reasons, when estimating the actual charging capacity of a mobile battery before purchasing, we recommend multiplying the capacity indicated in the specifications by roughly 66%
- We will tally up the mAh consumption per day of each device you bring
- Multiply this number by the number of nights you will be hiking (or the number of charges you will need before refilling)
- Divide the number obtained in step 2 by 0.66 to calculate the approximate required capacity (the mAh value displayed in the specifications)
Example: The battery capacity required to charge a smartphone (5,000 mAh) and a smartwatch (500 mAh) on an overnight hike is:
(5,000 + 500) mAh × 1 night / 0.66 = 8,333 mAh
By the way, in my case, if I were to charge all the devices listed above to 100%, the total would be 11,383 mAh, but in reality, I assume that about 60-70% of that would be sufficient, so the calculation is 7,000 / 0.66 = approximately 10,000 mAh (for a one-night mountain trip)
Point 2: Charging speed (output/input) – The USB PD (USB Power Delivery) standard is essential
Conditions for high-power, speedy charging
No matter how much capacity your mobile battery has, when you plug it in and try to charge it, it can be frustrating because it never finishes charging. Have you ever had that experience?
To avoid this, it's important to check the charging speed (= output) of a mobile battery when charging a device in order to choose the right product. Generally, the charging speed of a mobile battery is determined by the amount of power expressed in units of watts (W), which is calculated by multiplying the current and voltage as shown in the formula below
Power (W) = Voltage (V) × Current (A)
In other words, the larger the voltage (V) and current (A), the larger the output power (W)
The voltage and current values that can be selected when charging are selected based on the performance of each device, such as the minimum and maximum output allowed, and set standards, and the output power (= charging speed) is determined based on this
As electronic devices have become more sophisticated in recent years, battery capacities have continued to grow. This, combined with the growing demand for fast charging, has led to yearly advances in high-output, fast-charging mobile battery technology. As of 2022, one technology worth knowing about is the USB PD (USB Power Delivery) standard. When considering a mobile battery, we strongly recommend choosing a device that supports this standard
Going into all the detailed rules and exceptions would make this topic too complicated, so I'll just give a brief overview. "USB PD" is a standard for USB Type-C (connector/cable) established by a USB-related specification standards organization, and allows for much higher-output charging than conventional USB (Micro-USB) connections (Type A or B). Unlike the proprietary standards developed by individual manufacturers until recently, it offers high compatibility between devices, and is a noteworthy standard that is likely to become even more common in the future. A distinctive feature of the USB PD standard is that each device's connector is a "USB Type-C" type, and USB PD charging requires a cable with USB Type-C on both ends (although the iPhone still has a Lightning connector on one end)
One thing to keep in mind about charging speed, not just for USB PD, no matter how high-output a mobile battery is, it doesn't necessarily mean it will charge quickly . This is because whether or not you can charge quickly depends on three factors: the performance of the battery, the performance of the receiving device, and the performance of the cable connecting them .
Three conditions that determine charging speed
- Mobile battery output performance
- Output capabilities of the receiving device
- Cable output performance
Also, if you have a model with multiple charging ports (USB outlets) and are charging two or more devices at the same time, keep in mind that each port's output will be limited, making individual charging much slower than usual. If you have two high-power tablets plugged in, be prepared for charging to be frustratingly slow
The USB PD (USB Power Delivery) standard also has the fastest charging speed for mobile batteries
Just as the charging speed from a power bank to a device varies, the charging speed of the power bank itself also varies depending on the connector standard. If you want to charge faster, the current optimal solution is to charge with a USB Type-C port that supports USB PD. Doing so can reduce the charging time from over five hours for a 10,000 mAh battery to less than three hours (assuming you're using a compatible cable). This may not be much of a benefit for people who can charge slowly at home every time, but it's important for through-hikers who want to reduce the time they spend in town to resupply
Point 3: Waterproof, dustproof, shockproof, and temperature range compatible
When outdoors, you're faced with a variety of risks that are unimaginable in everyday life, such as dust, rain, snow, extreme heat, bitter cold, and even submersion in water or being dropped to the ground. For this reason, the more challenging the field you take your device into, the more you need to be vigilant about these risks and take precautions, otherwise you could suffer serious consequences if something goes wrong. For this reason, we recommend choosing a battery suitable for outdoor use that is durable and offers protection against the external environment
Waterproof/dustproof
First, there's the "IP protection rating," an objective indicator of a battery's resistance to dust and water. This is the same rating you'd see on headlamps. If you're looking for a model that can withstand bad weather, an IP67 rating or higher is ideal. "67" means that the battery is completely protected from dust and dust, and will not be adversely affected by minor submersion in water. This rating means that the battery will be fine even if it's exposed to rain or dropped into a river
Shock resistance
There are no universally accepted, objective standards for impact resistance (such as the US military MIL standard), but we recommend that you choose a model that at the very least has a shock-absorbing structure and advertises itself as "impact-resistant" in some way
Applicable temperature range
Finally, you need to be a little careful about the "temperature range" that's supported. Most mobile batteries today are made with lithium-ion batteries, and while there are minor differences, the safe operating temperature during discharge is said to be roughly between 5°C and 45°C (I'm sure many of you have experienced your iPhone quickly running out of battery at a cold ski resort). From what I've researched, while there are some differences, it seems that there are no general-purpose models that guarantee safe operation in sub-zero temperatures or extreme heat. For this reason, they are unlikely to function properly in extremely hot weather or when overheated, so they should not be used. Also, in extremely cold conditions such as on snowy mountains, there's nothing you can do, so you should try to keep the temperature as high as possible by placing them inside your clothes or sleeping bag .
Point 4: Weight and size
Mobile batteries are quite heavy, so naturally the lighter and more compact they are, the better, but as you try to ensure sufficient charging capacity, both weight and volume inevitably increase, so it's important to find the optimum balance. Furthermore, waterproof, dustproof, and shock-resistant models tend to be bulkier than models with the same power capacity, so you should aim to choose a model that is as light as possible while still offering the necessary capacity and durability
Point 5: Types and number of interfaces
Until now, most mobile battery interfaces (connectors) only had USB or Micro USB ports for charging, but more recent models are now equipped with the USB Type-C port used in many smartphones. If you're considering buying one, you should choose a model with a USB C port without hesitation (the reason is that, as we've already explained, it features USB PD, which allows for fast charging)
Regarding the number of ports, there is certainly a drawback in that charging speed will decrease when multiple devices are charged at the same time, but since there are often situations where you want to charge multiple devices while you sleep, it is best to choose a model with two or more ports of the types you need
summary
Mobile batteries, which are peripherals for smartphones and tablets, are often made by shady manufacturers, and it was difficult to find a list of products that are truly "usable" for outdoor use, so we decided to make this list. In this world where it's no longer possible to be confident that something is "made in Japan" or "made by this manufacturer," the products featured here are all ones that have actually been used successfully in the field, so please use this as a reference, along with some tips on how to choose one. Have a wonderful mountain trip!
Related reading
