Boxtron Hercules Z1 Energizer Ultimate Dark Energy Poseidon

The Best Portable Chargers

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Boxtron Hercules Z1

  • Solid construction
  • Light and easy to carry
  • Great value for the money
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Energizer Ultimate

  • Charges three devices at once
  • Big enough to hold several charges
  • Handy USB cord stays with the unit
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Dark Energy Poseidon

  • Made for the outdoors
  • Virtually indestructible
  • Power to go anywhere
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Portable battery packs are a handy item to have around. If you forget to charge your phone, aren’t near a power outlet, or just need some extra juice on an extended night out, bringing one along can keep the selfies flowing. But which one is right for you? Whether you’re an outdoor adventurer or simply always forget to plug your phone in, we’ve got the pack you need.


Boxtron Hercules Z1

Starting from $17

The Details

10,050 mAh charger for USB devices

Texas Instruments intelligent charging system

Qualcomm Quick Charge 3.0

Weighs 6.1 oz.

What / Who It's Best For

  • People who forget to charge their phones
  • People who use their camera a lot when they’re out
  • People who want a low-cost solution to their power needs

Why We Love It

Editor’s note: It appears Boxtron has discontinued the Hercules Z1 since the time of  publishing. The BuzzFeed Reviews team is currently putting together our new $ pick, and we’ll be updating this page shortly! 

If you’re looking to spend less than a 20 on some extra power, you can’t go wrong with the Boxtron Hercules Z1. While you may not have heard of the name on the outside, you’ve almost certainly heard of the names on the inside. To begin with, it uses the Texas Instruments intelligent protection system to keep the charger safe. This chip ensures that the charger switches off when it’s supposed to, stops it from overheating, and keeps it from damaging your device.  

Best Portable Chargers Boxtron upright

It’s also Qualcomm Quick Charge 3.0 certified, meaning that it will charge your phone as fast as your device will allow. For most of our tests, this little thing could take an iPhone 8 or a Samsung S8 from 0% to 100% in about 1 hour and 40 minutes, with some minimal use for texting and checking emails. This was consistent with the time those same phones took to charge from a wall outlet.

Battery Pack Facks…..uh, Facts: If you’re shopping around for a portable power solution and find yourself asking, “What the hell is a milliamp hour?” then great news! Marketing has done its job. They’ve intentionally made this harder to understand than it should be.

Okay, so y’know how it takes 1,000 millimeters to equal 1 meter? It’s the same thing here. It takes 1,000 milliamps to equal 1 amp, which is a unit of measurement that tells you how much electricity is being used. A milliamp hour, or mAh for short, is how much power a battery pack can provide in one hour. So when you look at the specs and it says “10,000 mAh,” all that means is that this pack can supply about 10 amps (or 10,000 milliamps) in one hour.

Why does this matter? Well, this is a good indication of how fast a charger can charge your device. As a point of reference, most phones can’t handle more than about 3.1 amps, so 10 amps is  fast enough to charge them in two hours or less. Those little lipstick chargers you can get at the bodega for five bucks usually can’t come close to that, which is why you can plug your phone into one of them, leave it for a week, and still only have 30% charge.

Best Portable Chargers Boxtron in hand

This is another reason the Z1 is the best choice at this price point: for about $15, you can pick up a charger that will do what you need — namely, bring your phone back from the dead in record time. During our tests, the Z1 fully charged a Samsung S8 about two times and an iPhone 7 about three before it needed to be recharged, which takes about 6.5 hours. This was similar to most others on the higher end of this price range, meaning the Z1 holds its own against higher-priced chargers. It has one USB outlet, charges via mini-USB, and comes with a high-quality, braided gray nylon USB-to-mini-USB cord.

There are four LED lights to let you know how much power is left. You simply hit a button to turn it on. Small and light, this little charger is well worth the money and will keep your phone going with hours of power.

User Reviews

“This charger works well, and it does in fact ‘fast-charge’ your device if your device is capable. It's able to charge my Note 8 about three times before needing to be charged. This worked perfectly on my hikes in Hong Kong. Shipping was fast!”
— Michael S. From Amazon
“Works great. I took five one-hour videos in one day on my phone (taking video for a basketball tournament) and used this to charge in between games, and it worked flawlessly. No issues with heat or anything. Never even ran out of battery (although I was charging it any chance I got while driving around or using my laptop).”
— Jason A From Amazon
“Takes a long time to fully charge and a little heavy, but worth it for peace of mind when I'm stuck on delayed trains, which happens often. Able to fully charge two phones with barely any loss of power and charges any USB-compatible equipment. Holds charge for at least a week when not in use.”
— the metal guy From Amazon


Pocket-sized power

Where to buy

$17 at Amazon

Energizer Ultimate

Starting from $49

The Details

5.8" x 3" x 1" inches

Weighs 15.5 oz.

Solidly built with integrated USB cable

Qualcomm Quick Charge 3.0

3 USB ports for charging multiple devices

LED power indicator

What / Who It's Best For

  • People who need a bit more power
  • Frequent flyers or travelers
  • People who also need to charge their tablet

Why We Love It

If you consistently find yourself forgetting to charge your phone, you might need something that packs a bit more power. If that sounds like you, the Energizer Ultimate is the way to go. While the Boxtron Hercules can charge a Samsung S8 about twice before it dies, the Energizer can double that, charging an S8 four times and an iPhone 7 about six times (also double the Boxtron).

That bigger capacity also means a bigger battery — and the Energizer Ultimate is certainly big. While it wasn’t as hefty as some of the other units we tested, weighing in at just over a pound means you won’t be carrying it around in your pocket. This portable charger is probably better suited to frequent travelers than to hikers.

The Energizer Ultimate has a few small details that help it stand out from the crowd. For one thing, it’s white, while most external battery packs are typically black — an advantage for finding it in a dark backpack or dimly lit space. Its charging cable is integrated into the body of the unit, meaning that you always know where it is, and it won’t get tangled up in the rat’s nests of charging cables, other charging cables, adaptors, and headphones that plague the modern human. Those may not initially seem like big bonuses, but after a while we really started to appreciate how low-maintenance this thing is.

Best Portable Chargers Energizer USB attachment

Battery Pack Fact: Qualcomm Quick Charge is a technology for managing power delivered via USB. Quick Charge 1.0 was released in 2013 and Quick Charge 4.0 in 2017; however, most current devices are certified for Quick Charge 3.0. Almost all USB ports can deliver about 2 amps of power, but with Quick Charge 3.0, the output can be as much as 4.6 amps, which means faster charging.

The Energizer has an input of 2 amps and an output of 4.5 amps, meaning it can charge itself and your device pretty quickly, even if your phone doesn’t have Quick Charge (or QC, as the cool kids say). During tests, the Ultimate charged a wide variety of phones from 0% to 100% in approximately an hour and a half, which was pretty standard among the battery packs in this price range. It could also charge a regular-sized iPad about 1.75 times before dying, which was NOT standard.

Tablets and iPads tend to have internal batteries just as big as the battery pack itself and will suck the juice right out of one. We tested a few that could charge tablets a couple of times, but they were so big and heavy that calling them “portable” was really stretching the truth. The Energizer is one of the few that can hold enough power to charge an iPad even once, let alone almost twice.

Best Portable Chargers Energizer in hand

It does take a while to charge itself, though — seven to eight hours — but again, that’s not unusual for battery packs. It also has a four-LED system for indicating the remaining charge, which you access by shaking it (which is kinda funny). For a good midsize power-pack solution, the Energizer Ultimate does the trick.

User Reviews

“I love this very cute portable charger. When I'm at work, I just plug it into my computer to charge it. When taking pictures at events, it is the best way to keep the juice flowing in your phone. I only have one piece of advice — ladies, when you are carrying it in your purse, be sure to have it in a secure area, such as a pocket. I had it attached to my phone in the bottom of my purse. When I got home I found that the charge port on my phone had broken (the prongs had broken off).”
— P. Newon From Amazon
“Got this on sale, forget exactly what the price was, maybe $37.50 or so. Anyway, the only drawback to most of the batteries is weight (can't really find a workaround for solving that); the second is cables. This was purchased for charging specifically LG phones with USB-C. The included short cable does not have the USB-C but is USB micro; we had some adapters lying around, so we now have to pack those or just use the factory LG cables. This will charge the LG V20 in about 1 hour and 15 minutes, a GoPro in 1 hour, and a Sony HX-400 camera in an hour and a half.”
— CBNo1RN From Best Buy
“This portable power pack for your smartphone allows you to do things like fly on a plane for seven hours and keep using your smartphone without any power outlets. The charger is well-designed and easy to use. Plug it into your USB port or smartphone charger and it will charge itself. Once it is charged, you can bring it along and plug your phone (or other device) into it for extra power. Your phone then charges itself off this external battery. Likes: - Simple to use. - Big capacity. Dislikes: - Not everyone needs one of these. Overall, great gadget — it allows me to play games for hours on my smartphone when stuck on a long flight.”
— A. Fabbri From Amazon


It really does keep going and going


Dark Energy Poseidon

Starting from $100

The Details

6" x 0.8" x 3.5" inches

Weighs 11.2 oz.

Military-grade exterior

IP68-rated for dust and water

Built-in flashlight

Paracord charging cable

What / Who It's Best For

  • Campers, hikers, and other outdoor enthusiasts
  • People who need a rugged power solution
  • People who work or play near water

Why We Love It

When Special Forces guys crawl into their jungle beds at night after a hard day of doing secret Army stuff, they probably like to unwind with a good game of Candy Crush. Or maybe it’s Angry Birds. We can’t say for sure, because that’s probably classified information and the Department of Defense ignores our emails, but what we can safely assume is that those guys are using the Dark Energy Poseidon to charge their devices, no matter what casual mobile games they play.

We can’t say that the Poseidon had the largest capacity of the battery packs in this category, because it didn’t. And we can’t say it was the cheapest, because at $110, it very much wasn’t. But darn it, did we use this thing ALL of time. It was so easy to just slip into a pocket and forget about until we needed it. One of our testers even took it on a canoeing trip, forgot he had it on him, and jumped into the water. Since it’s IP68 rated for water and dust, this means it is virtually waterproof, and this little episode was merely humorous and not at all an issue. The Poseidon showed no ill effects after it had been dried off and continued to provide power up and down the river.

Best Portable Chargers Dark Energy in hand

Battery Pack Fact:. You might see input and output mentioned in the product specs, and again, this has to do with power. Input is how much power the battery can draw to charge itself; output is how much power it can provide to whatever device it is charging. This also translates to how fast it charges your devices.

You may have noticed that some USB wall plugs can’t seem to charge your phone in less than a fortnight. If that’s the case, look on the back. You’lll usually see numbers that look something like this: “Input – 1A. Output – 1.5A.” That’s 1 amp and 1.5 amps, respectively, which is pretty low and explains why it takes 40 forevers to charge your stuff. Generally, you want the output to be at least 2.1 amps.

Best Portable Chargers Dark Energy ports

The Poseidon has two ports, one with an output of 2.4 amps and the other at 1.0, for a total of 3.4 amps. Although it is not rated for Quick Charge 3.0, it was still capable of charging a Samsung S8 in about 1.5 hours. This meant it was almost exactly as fast as the ones that were QC 3.0 certified.

As small as it is, we didn’t expect it to be able to charge a smartphone as many times as the larger battery packs, but were surprised to find that it could hold about 3.5 charges for the S8 and almost five for an iPhone 7 before needing to be recharged, which took close to seven hours. Like most of the others, it also has a four-LED light system to let you know how much juice is left; unlike the others, you can clip this one to the outside of your backpack and forget about it. It says it’s MIL-STD-810-G rated, and although we don’t exactly know what that means, we do know that you can accidentally bang it on several rocks on your way down a waterfall because you forgot it was there and it will still work.

Best Portable Chargers Dark Energy carabiner and flashlight

The built-in flashlight and carabiner clip that come with the Poseidon are designed to make you feel like you could jump out of an airplane with this thing and it wouldn’t even blink. Given what we put it through during testing, we have to believe it.

User Reviews

“Quickly becoming my favorite power bank due to its IP68 rating, which was accidentally tested due to my oversight. Not a single issue!”
— matt ~ ohio From Amazon
“STRONG, SOLID-MADE PRODUCT. Holds charge and can charge four iPhones or two tablets and two phones. Really solid product. Durable as can be.”
— Christopher Levy From Amazon
“I take this with me everywhere. I’ve never dropped it or submerged it in 6 feet of water, but I do use it for my shit iPhone battery, and I get about two charges (not three to six, like they claim). It takes all night to charge and my cable cap broke after about six months. But I will say this: I’d buy it again. When my iPhone has decided it’s gonna burn through 40% of my battery in about 10 minutes, my Poseidon has come through in the clutch.”
— Ryan From Amazon

Dark Energy

Battle-ready battery

Where to buy

$100 at Amazon