There’s two things you should know about me, your intrepid reviewer: I hate the feature creep associated with modern power banks, and I love shaving grams off the gear I carry when backpacking, bikepacking, and trail running. So imagine my delight when Nitecore released a new generation of its ultralight NB10000 battery. After a few weeks with it I can confidently say: Haribo be damned!The $83.95 NB10000 Gen 4 weighs just 146 grams, according to my scale, and measures 1.45 x 11.6 x 4.68cm (0.57 x 4.57 x 1.84 inches), according to Nitecore’s spec sheet. That makes it the lightest and most compact 10,000mAh power bank I can find. Even when factoring in the extra 6 grams added by the included USB-C lanyard, it still beats the previous ultralight champ: Nitecore’s NB10000 Gen 3. The secret to the Gen 4’s impressive weight is a silicon-carbon anode, the same battery tech increasingly appearing in flagship smartphones, including Samsung’s.As small as it is, the Gen 4’s 39Wh battery still fully recharged my aging iPhone 15 Pro twice, with a few watt-hours left in the tank. And with up to 22.5W of output, it can even top-up my 14-inch MacBook Pro when needed. It also supports pass-through to charge your gadgets as the power bank itself charges.Have I found power bank perfection? Almost.8Verge Score$84The GoodClass-leading energy densitySmallest and lightest 10,000mAh aroundGreat for endurance athletes and backpackersImpressive water resistanceThe BadExpensiveKnock-to-wake is hit-or-missSilly RGB lightingI like that the NB10000 Gen 4 gets all the basics right. It has a simple, four-element indicator to show the battery level, which I much prefer over a fancy display. It’s constructed out of carbon fiber sheets and offers IPX7 protection against water ingress, allowing it to withstand rain or even temporary submersion – exactly what you want from an adventure battery.In my testing, I measured 33.58Wh of the claimed 39Wh capacity for an 86.1 percent efficiency. That’s a pretty good result for a premium power bank and a slight improvement on the 33.33Wh we measured on the Gen 3 model. That works out to 229.98Wh/kg of delivered energy, or 220.90Wh/kg with the cable — class-leading results, either way. The NB10000 Gen 4 supports PD, QC3.0, and Huawei’s SCP charging protocols.The Gen 4 battery on top of an iPhone 15 Pro. It’s very small for the charge capacity it holds.The RGB lights are pretty but a little superfluous and that button is touch-sensitive instead of mechanical. Silly.Carbon fiber shell with strong IPX7 resistance to water ingress.Supports pass-through charging to charge and be charged simultaneously.The Gen 4 model also didn’t suffer from the overheating and shutdown issues we saw when the Gen 3 would run low on juice. I did, however, see a temporary interruption in power delivery when the Gen 4 unit was almost fully depleted, but that’s only because I had a meter attached — otherwise I wouldn’t have known since it continued charging almost immediately.The only thing that could be considered superfluous is the animated RGB lighting that flows around the dual USB-C ports. The lights are there to guide you to the USB-C ports in a dark tent, says Nitecore, but you can also… feel them. Give the battery a double-knock near the top and the lights (and battery indicator) illuminate. This can be helpful if wearing gloves since Nitecore inexplicably opted for a touch-sensitive wake button on the Gen 4. Fortunately, that so-called “Touch Button” did reliably sense my wet finger in testing. The knock-to-wake feature seemed to only work about 75 percent of the time, but it, and the RGB lights, can be disabled if you want.1/8The lanyard is actually a braided USB-C cable rated for up to 60W.The lights will also glow yellow (regular mode) or green (eco) after a long press of the power button if you want to toggle between full power and extended life, respectively. Eco mode works by dropping the output to a slow 5W (5V at 1A) max. This can keep the power bank from automatically shutting off when charging low-draw devices like headlamps, watches, or wireless earbuds. It can also yield a little more total charge capacity by producing less heat waste, and allow the battery to operate closer to its native voltage resulting in less conversion loss.The Nitecore NB10000 Gen 4 is the ideal power bank for endurance athletes, backpackers, or anyone looking for an ultralight and ultracompact power bank that mostly avoids feature creep. The only real negative is the price, having gone up to $83.95 since the launch of the $64.95 Gen 3 model two years ago. That makes the Gen 4 power bank two to three times more expensive than the typical 10,000mAh power bank, but it can save you 50 grams or more. That’s a price premium I can see lots of active, outdoorsy people happily paying for.All photos by Thomas Ricker / The VergeFollow topics and authors from this story to see more like this in your personalized homepage feed and to receive email updates.Thomas Ricker