Tested: NRG Power Stem – charging on the go

The NRG Power Stem is an innovative take on bike components, integrating a 3,500mAh power bank directly into the stem to charge devices on the go. As someone who likes to keep my bike looking clean and uncluttered, I was keen to try it out. On long rides, I’ve often had my GPS, phone, or lights run flat, and carrying an external power bank is bulky and awkward. The idea of having charging built into the bike itself is a clever solution – though it does come with a few limitations.

First thoughts

Out of the box, the NRG Power Stem feels solid and well-made, with a smooth, clean finish. It’s lighter than I expected for something with a built-in battery, and gives the impression it’s been put together with care.

Installation

As with most stems, installing the NRG Power Stem is straightforward, requiring just two Allen key sizes. It’s recommended to use a torque wrench when tightening bolts, and it’s especially important on such a crucial part of your bike.

Weight

Weight is an important consideration for any permanent component. Generic alloy stems of similar length typically weigh between 130-170g, whereas the NRG Power Stem comes in at 240g – an added 60g or more. For weight-conscious riders, that might be a dealbreaker. I was happy with what I saw as a small trade-off, especially after expecting the battery and electronics to add a few hundred grams. After all, 60g is just one less gulp of beer the night before your ride.

Size

Currently, the NRG Power Stem is only available in one size –103mm long with a 5° angle. While this would cater to many cyclists, it’s not a size that will suit everyone. Hopefully, with some success, NRG will expand the range to include both larger and smaller options, as the current sizing limits who the stem can truly accommodate.

Performance

When it comes to charging, the NRG Stem delivers a reliable, steady output capable of charging phones, GPS computers, lights, or even cameras without issue. The built-in temperature cut-out safety feature is a thoughtful inclusion, preventing overheating during extended use.

While 3,500mAh is smaller than most cyclists, including myself, would ideally want, it’s a fair compromise. More battery capacity would mean more weight; for most rides, 3,500mAh is more than enough to get you out of trouble. I’ve successfully topped up my front and rear lights, as well as my iPhone, during a long day out.

I found it easy to charge items with different charging ports because the stem includes a universal USB port and comes with a two-metre charging cable, micro USB cable, mini USB cable, USB-C cable, lightning cable, and custom cable clip.

Conclusion

One thing I love to see in the sometimes stagnant cycling industry is innovation, and the NRG Power Stem is just that – an innovative way to solve an age-old problem. Its clean design and integrated battery pack offer convenience while helping reduce cockpit clutter.

It’s not perfect – the single size option won’t suit every ride, and the 3,500mAh capacity won’t cover ultra-long adventures. That said, for everyday rides where you’re out on the bike for hours at a time, it’s more than enough to top up devices on the go.

Overall, it’s a clever product that blends practicality with thoughtful design. If NRG expands the size range and continues refining the concept, it could become a go-to for riders who value both tech and simplicity.

Technical Specifications

Battery Capacity: 3,500 mAh (Lithium-ion)

Output Power: 5V / 2.4A (typical charging current)

Charging Time: Approximately 2–3 hours for full recharge

Material: Heat-treated aluminium alloy (stem body)

Compatibility: Designed for standard 1-1/8” (28.6 mm) steerer tubes. Compatible with most modern road, gravel, and mountain bikes with this steerer size

Safety Features: Overcharge protection, Over-discharge protection, Over-current protection, Temperature cut-off to prevent overheating

Water Resistance: Weather-sealed, splash resistant (not fully waterproof)

Dimensions: Length: ~103 mm, 5° Angle. Clamp diameter: 31.8 mm (handlebar clamp size standard)

Weight: Approximately 240 grams

Retail price: $195.

More info nrgstems.com/