This photo shows the Dark Energy Poseidon Pro Charger charging a Garmin InReach Mini satellite messenger device.

Dark Energy Poseidon Pro Charger Review

- Field-tested -

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The Dark Energy Poseidon Pro Charger is a ruggedized, waterproof portable battery pack for charging mobile devices in outdoor environments.

To get us a closer look, Dark Energy sent us a review unit. After using and testing the Poseidon Pro out in the field in cold and wet conditions, this is what we learned:

Poseidon Pro Charger Review

While there are many portable rechargeable battery chargers these days, most of the competition is not rugged or waterproof. The Dark Energy Poseidon Pro Charger is both rugged and waterproof. At first glance, the Poseidon Pro looks like a drop-ready burly phone case. The corners feature rubbery bumper guards, and the side polymer construction seems tough, too.

This photo shows the Dark Energy Poseidon Pro Charger charging a Garmin InReach Mini device.
The Dark Energy Poseidon Pro Charger is waterproof, rugged and ready for outdoor activity.

Dark Energy says the Poseidon Pro is certified to military standard MIL-STD 810G and has an IP68 certification rating. The MIL-STD 810G focuses on overall ruggedness and performance while the IP68 rating means it’s completely dust-proof for small solids like sand and dust, as well as waterproof below one meter for more than 30 minutes.

This means you can take the Poseidon Pro backpacking without needing a waterproof bag or case, as well as take it rafting or kayaking with little fear. You could also toss it into a fishing backpack or into a fishing hip pack without needing those packs to be waterproof. I always keep a battery charger ready in my hunting pack, and the Poseidon Pro’s ruggedness means you can stow it in a non-waterproof hunting pack pocket with little fear of rain.



In our testing the Poseidon Pro handles dust and sand very well — no ingress — but you’ll want to blow off the edges of the port flap and hinges before opening it because you can get a bit of debris in those tiny seams.

As for water, I submerged it in a bowl of water and pushed and banged it around to see if some bumps or physical pressure could disrupt a seal and compromise it. No water entered and it works fine.

Of course, the IP68 rating means it’s mostly waterproof — if you drop it into 8 feet of water, I would guess the Poseidon Pro would survive for a few minutes until you could dive down to retrieve it. Just remember that pressures beyond a meter will eventually allow water seep in.

10,200 mAh Capacity

This photo shows the Dark Energy Poseidon Pro Charger outside on a rock with water droplets.
The 10,200 mAh capacity is enough to fully recharge common smartphones 2.5~ times. In case this isn’t clear, the Poseidon Pro is only waterproof when the ports are covered . . . not when you’re charging devices with it.

Forget the number of hours of power that a battery pack can extend for your device. Additional ‘hours’ of usage is not a particularly useful metric because every device is too different to lead anyone toward a meaningful measurement. Instead, focus on the capacity of the battery charger itself.

In this case, the Poseidon Pro has a 10,200 mAh battery. To put this in perspective, an iPhone 13 has a battery capacity of 3,227 mAh. This means you’ll be able to recharge your iPhone 13 approximately three times with the Poseidon Pro. Of course, in the real world you don’t get 100% efficiency when charging devices — some energy is lost based on voltage, output types, internal electronics and temperature. If you consider the capacity in terms of 85% being available for charging, you’ll get around 2.7 charges for an example iPhone 13 (maybe a bit less in very cold sub-freezing weather).


The Waterproof Flap

This photo shows the waterproof flap on the Poseidon Pro Charger.
The waterproof door shows the light and ports underneath.

Aside from a rugged sealed case, the charging ports aren’t waterproof and need protection. Dark Energy solves that by using a hinged flap with a rubber gasket. It snaps shut with enough pressure to inspire confidence but isn’t hard to open. It’s very good actually, one of the better ‘waterproofing’ electronic device covers I’ve used.

One risk to waterproof device covers with rubbery gaskets is that it could wear in and become looser over time and extended use. I wouldn’t worry about it, but it’s something to be aware of. The more likely culprit if you plan to use the Poseidon Pro in wet environments is if a tiny bit of sand goes unnoticed when you close it, which could compromise the seal. Waterproof cameras have this risk, too, by the way. Just blow it off and inspect it before you close the flap.

Charging Ports

This photo shows the charging ports on the Poseidon Pro Charger.
Small flashlight to the left, USB-C for in/out charging in middle, standard USB out to the right.

The Poseidon Pro has two charging ports: The USB-C port is for both charging in and out while the standard USB port is for out charging only. Dark Energy says that if you use a USB-C to USB-C charging cable, you can improve charge times up to 2.5x faster. Nice.

Dark Energy also includes a small flashlight bulb. The light doesn’t put out a lot of lumens — barely any — but it’s perfect for quick use when you’re looking for something in the dark in the bottom of your pack. The button is on the outside of the case. Press it once for a steady light, twice for a blinking intermittent light, and a third time to turn it off. The only drawback is that you have to open the port flap to use the light — so it’s a no-go if it’s raining out.

If you accidentally press the light button, the light will come on, potentially draining your battery. To alert you of such a press, Dark Energy lights up on of the green battery light indicator lights on the side of the case.

The button on the other side of the case from the flashlight button is a battery indicator button. Four green lights to tell you the relative percentage of battery power that’s left.


Competition & Alternative Options

While there are many portable rechargeable battery packs available these days, there are distinct differences in quality and longevity. While you can buy a portable battery pack at a gas station, don’t expect that pack to last very long — it might give you many charges over several months or it might die in a few weeks. Dark Energy says its Poseidon Pro is designed to last 3+ years. In our experience, most decent battery packs last 12-24 months depending on how often you use them and how often you completely drain their batteries. More use with more frequent complete drainage tends to shorten battery pack life. (The Poseidon Pro is in rotation for longer-term use to test this, and it’ll spend some quality time while rafting this summer in case a long-term review update is warranted.)

In any event, one option to ‘waterproof’ a portable battery charger is to invest in a quality waterproof case like the SealLine E-Case. The biggest benefit here is it lets you buy a quality non-waterproof charger at a lower price point. This solution has the added benefit of giving you a spot to stow your phone and/or electronic vehicle keys. The drawback is increased bulkiness and extra stuff to manage.

Without a separate waterproof case, consider these options:

GoalZero Venture 75 — The GoalZero Venture 75 is a high-quality USB-C rechargeable power bank with a whopping 19,200 mAh capacity. Like the Poseidon Pro, it’s waterproof. Unlike the Poseidon Pro, its waterproof rating is slightly lower. With its IP67 rating, it can withstand submersion up to 1 meter for at least 30 minutes.

myCharge Adventure H20 Turbo — The myCharge Adventure H20 Turbo is available in two sizes, a 10,050 mAh option and a 20,100 mAh option. mCharge claims that both are waterproof but doesn’t report a specific rating — so we recommend that you consider them only highly water-resistant.

If you have a waterproof case, consider BioLite:

BioLite Charge 40 PD — The BioLite Charge 40 PD is a high-quality fast-charging USB-C rechargeable power bank. One key benefit is that you can charge multiple devices at the same time. It has a 10,000 mAh capacity, but you can get the smaller Charge 20 or larger Charge 80 if you want a different size option.

The Bottom Line

All-in-all, the Dark Energy Poseidon Pro Charger is a rugged, waterproof rechargeable battery bank that’s designed for wet and dusty outdoor use. While it’s not waterproof while you’re using it to charge devices, the protective port flap does a great job of sealing out the elements so it’s ready to charge when you are.

Get the Gear:

Dark Energy Poseidon Pro Charger
IP68 dustproof/waterproof rating
Ruggedized shell with burly bumper guards
Includes newer USB-C port for faster charging
Costs a bit more than the competition
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