If you’ve been following the ultralight gear scene, you know the Nitecore NB10000 (review here) and new NB Plus (YouTube review here) have ruled the roost for years. Flextail has clearly decided to challenge that throne with the Zero. It is billed as the world’s lightest 10,000mAh power bank, and while the weight savings over its competitors are measured in grams, the usability tweaks make it a very compelling option for the backcountry.
For a hunter or ultralight backpacker, weight is everything, but form facter and “pocketability” matter too. The Flextail Zero brings a forged carbon fiber shell and some thoughtful lighting choices that make it feel like it was actually designed by people who sleep in the woods.
Note: Flextail sent me this battery bank for review.
Specifications
- Capacity: 10,000mAh (38.7Wh)
- Weight: 145g (5.1 oz)
- Dimensions: 4.8 x 2.34 x 0.39 inches
- Case Material: Forged Carbon Fiber
- Input/Output: Dual USB-C ports
- Max Output: 22.5W (Fast Charge) Can also do a 5W slow/efficient charge.
- Max charging rate: 18W
- Water Resistance: IPX4 (Splash resistant)
Usability
The first thing you’ll notice is the USB-C cable/lanyard. It’s a short, reinforced cable that clips into a connector that then loops through the corner of the housing. It’s a brilliant “quality of life” feature because it ensures you always have a charging cable attached to the unit. No more digging through your electronics pouch at 10:00 PM trying to find a cord.
One of the most underrated features is the LED indicator. Most electronics companies use high-intensity blue or white LEDs that can light up a whole tent. Flextail went with a dull orange light. It’s easy on the eyes in total darkness and won’t blow out your night vision or keep you awake while your phone tops off overnight.
It also features two distinct modes:
- Fast Charge Mode: Pushes 22.5W to get your phone back to 50% in about 26 minutes.
- Efficiency Mode: A lower-voltage mode (5V/1A) that Flextail claims reduces power loss by 30%. In plain English: if you aren’t in a rush, use this mode to get more total “juice” out of the bank.
Competitors
- Nitecore NB10000: The primary rival. The Nitecore is slightly more water-resistant (IPX5 vs IPX4), but the Flextail is marginally lighter and often a few dollars cheaper.
- Anker 523 (PowerCore Slim 10K): Much cheaper and very reliable, but significantly heavier and bulkier. It’s a great truck-charger, but not as great for hiking up a mountain where you want less weight.
Conclusion
The Flextail Zero is a specialized tool for the person who weighs their gear before it goes in the pack. It’s tough, incredibly thin, and the forged carbon fiber shell handles the bumps and temperature swings of a mountain hunt better than standard plastic banks. The inclusion of the lanyard cable and the night-friendly orange LEDs show that Flextail is paying attention to the details that actually matter in the field.
