This power bank can be used underwater (but we don’t recommend it)

The other day I was checking out what I consider to be one of the best waterproof power banks I’ve come across. But it has one caveat – it was only waterproof when the little rubber covers protecting the ports were in place.

Not a massive limitation, but what are the chances of me forgetting to put the rubber covers on before the critical point where the power bank got soaked?

Quite high.

What I want is a power bank that is waterproof without the need for little rubber covers over the ports.

I found one That NiteCore NBP4.

The NPB 4 has multiple fast charge outputs and offers a maximum power output of 18W, which is enough for things like smartphones and tablets, but not for heavier loads like laptops.

The power bank has enough energy to charge an iPhone about half a dozen times or AirPods a whopping 32 times, and yet the power bank is small enough to be allowed on commercial aircraft.

On the side of the NPB 4 is a touch sensor battery level indicator that shows three blue LEDs when the battery level is approximately 100%, two lights for 70% and one for 30%.

Oh, and if you’re wondering what those little clips on the side do, well, they got me confused too. Apparently they allow the power bank to be connected Nitecore’s HU60 LED headlamp.

If you don’t have these headlamps, they’re a handy fidget tool.

From a safety perspective, the NPB4 has everything you’d expect from a modern power bank, including over-current protection, over-discharge protection, and short-circuit protection, and it’s all encased in a fire-retardant polycarbonate shell.

But it’s the waterproofing that I really like here. Normally, power banks are only waterproof if you cover the connections with rubber seals. Not the case with the NPB 4. Notecore used a high-strength o-ring on the charging port and advanced adhesive molding technology to protect the internal components from water.

And it works really well!

But can you use it underwater?

Well, Nitecore says you can. Here’s a video showing it charging and powering three devices while underwater:

I tested this and yes it works well underwater. However, I would be cautious for several reasons.

First, while it should be safe to charge underwater, I’ve encountered poor quality or faulty chargers where the metal parts are mains related (fancy word for plugged in). I wouldn’t want my hand in that water if that was the case.

Second, water will seep into the wires and connectors, potentially causing small shorts. In my experience, some USB devices can start behaving strangely when this happens and there is a chance of corruption.

The Nitecore manual is also quite reserved when it comes to water:

For this reason, I do not recommend you to use the power bank underwater. If you do so, the risk is on you. I would also keep it away from salt water and chemicals.

However, this is a power bank that I have happily left outside for long periods of time to power a camera or GoPro and let it get wet during use. It is highly resistant to rain and condensation, and the risk of problems is far less than if the power bank was submerged.

Likewise: GoPro Hero 11 Black First Look: The world’s best action camera gets even better

All in all the Nitecore NPB 4 is an excellent power bank. Loads of capacity, easy to use, robust and reliable, and a level of waterproofing that gives me a lot of confidence in the product.

It’s not cheap, but good power banks aren’t cheap.

If you’re in the market for a smaller power bank, Nitecore makes those too 5000mAh NPB 1and a 10,000mAh NPB 2.