Wurkkos H1 Powerbank

I recently found myself with dozens of 21700¹ Li-ion cells, but I had no specific application in mind. I wanted to see if I could use them to charge a phone with minimal weight over the bare cell. I went looking for a power bank that had a user-replaceable cell. However, there weren’t many options on the market. Nitecore advertised an option that used a 21700 cell, but some quick research indicated the cell was not user-replaceable. Nitecore also offers an option that utilizes their proprietary 21700 battery, which features the anode and cathode on the top of the cell. While this enables some very lightweight designs, it didn’t help me utilize the standard 21700 cells I already owned. All the other 21700 charger cases worked with two or more 21700 cells rather than just one.

The best option I found for a user-replaceable power bank that used one standard 21700 cell was the Wurkkos H1. Its listed specifications were quite promising:

• IP68 waterproof
• Durable metal case
• USB-C input and output, USB-A output
• 20W charging and discharging
• User-replaceable 21700 cell

I didn’t know anything about the brand, but some users on Reddit reported some success with it, so I figured I would give it a try. I wanted to purchase the power bank without an included 21700 cell, as I already had many of them. However, I could not find any in stock, so I had to purchase the charger with an included cell. I performed all testing with the included cell.

Features

The H1 is a minimalist power bank. It has a status light indicating 60-100% charged, 20-60%, and <20%. I wish it had more a granular charge indicator. Wurkkos claims it is IP68 waterproof, meaning you could submerge it in water up to 1 meter. It supports simultaneous USB-A and USB-C output. The H1 charges via the USB-C port. It can charge and discharge at 20W using USB-C PD protocols. There aren’t too many more features to speak of here. Other than the subpar status indicator, the H1 balances features and compactness well.

Build Quality

My first impression upon opening the box was that this power bank was well-built. It boasts an all-aluminum enclosure. There are gaskets on the threads and a rubber plug covering the charge ports, which helps keep water and dust out. I figure this will be able to live up to its IP68 rating. It comes with a removable clip that feels solid. Overall, I would feel very comfortable throwing this in my pack and not worrying about it. The power bank weighs approximately 134g (4.73 oz) with the clip attached and 125g (4.41 oz) with the clip removed. The included 21700 cell weighs 68g (2.4 oz).

Included Accessories

As previously mentioned, the H1 features a removable clip. I took it off immediately to save some weight (9g). It comes with a USB-A to USB-C cable. I would’ve liked to see a USB-C to USB-C cable that was a bit shorter, as all of my higher-wattage USB chargers only output USB-C. It also comes with a lanyard that can thread through a small hole on the power bank.

Capacity

The listed capacity of the 21700 cell is 18Wh (5000mAh @ 3.6V). This about standard for 21700 batteries, though I’ve seen some have at much 21.7Wh, like this one from vapcell. For reference an iPhone 16 Pro battery is 13.94 Wh, so I hoped I’d be able to get a bit more than one charge out of the cell, which is reasonable considering its compact size. However, I found that I was able to get less than a full charge. Only going from 1% to 82% on a full charge using the stock cell. The real-world capacity is somewhat disappointing, and I’ll elaborate on why I believe this is the case in the testing section.

Power Testing

I wanted to see how this power bank performed in the real world, so I purchased an RD TC66 USB-C Tester, which would allow me to monitor the voltage and amperage going in or out of the power bank in real-time and log the data over a long experiment.

Charging the Powerbank

It took about 90 minutes to charge from empty² to full. The charging curve was typical for a lithium-ion battery, initially operating at full speed of about 18 watts for a while, then slowing down to a lower speed until it reached maximum capacity. The highest power I saw, 18W, was 2 watts below the claimed charging speed of 20W, but it’s close enough.

Charging a device with the power bank

My primary use for using a power bank like this is to charge my phone on backpacking trips and expeditions. My iPhone 16 Pro has a 13.8Wh battery, which is approximately 75% of the capacity of the 21700 cell included with the Wurkkos H1. I discharged my phone down to 1% and then observed the charging behavior with the USB-C PD Tester. It was able to charge my phone to 80% in about 60 minutes, almost as fast as a wall charger. It then trickle charged to 82% before the battery couldn’t charge the phone anymore. Integrating the test results, the charger delivered 13 Watt-hours of power. I was honestly quite disappointed with this result, as it claims to be an 18Wh battery. The H1 purports to be able to charge a device at 20W, and it did get quite close to that for 15 minutes. It did get pretty close to what the 20W wall charger can do - 1% to 85% in one hour. During this process, the power bank became quite warm to the touch. I measured it at about 120°F. That’s on the high end of normal discharge temperatures for a battery and will impact its performance and lifespan.

I suspect the reason for the inefficiency is that the power bank has to use a boost converter to take the 3.6V of the battery and output 12 Volts. To get the peak charge rate we saw, 1.5A at 12V, the power bank is drawing roughly 5 amps from the cell, which will reduce the effective capacity of the cell. I haven’t been able to identify what chip this device uses, but boost converters often have efficiencies of 80-95%, which means that for every 10W of power drawn from the battery, you might only see 8W of output. The power testing with the H1 I conducted suggests an efficiency of 72%. The included USB-A to USB-C cable is not capable of USB-C PD, and thus charges a device at a much lower 6W. During the charge test with the included cable the H1 did not get nearly as hot. However, the H1 stopped charging my phone at a similar 82%.

Bottom Line

This device performs worse than other power banks I’ve used in the past and isn’t lightweight for its meager capacity. Where a power bank like this might shine is on longer trips where you could bring as many cells as you wanted to carry. If one were to need 500Wh of power (about 40 phone charges), a Goal Zero YETI 500 weighs 16.1 pounds, whereas a H1 and 28 cells would only weigh about 4.5 pounds. The H1 fulfills a niche use case.