Review: Deuter AC Lite 23 and AC Lite 21 SL Daypacks

Deuter AC Lite 23 and AC Lite 21 SL
$110, 23L/1,404 c.i., 2 lbs. 1 oz./920g (AC Lite 23)
One non-adjustable size in men’s and SL/women’s models

On a two-day hut trek in New Hampshire’s Presidential Range in June sunshine and high humidity, a friend and I hiked 21 miles with about 6,000 cumulative feet of elevation gain and loss each day, including scrambling up the steep slabs and talus of what’s widely recognized as the hardest trail in the White Mountains: Huntington Ravine, and descending some little-used trails in steep terrain and clambering over the broad, rock-strewn bed of the Dry River. Through the countless high-stepping and four-points-of-contact movement and the hours of streaming with sweat, the Deuter AC Lite 23 demonstrated its strengths of comfort and back-cooling ventilation.

The AC Lite daypacks come in four models—the AC Lite 23 and 24 and AC Lite 21 SL and 22 SL—each in one size with a fixed, or non-adjustable suspension, with the two larger packs designed for bigger torsos and marketed as men’s-fit (torsos 17-21 inches/44-54cm, according to Deuter) and the SL models designed for shorter torsos and built to fit women (torsos 15-19 inches/38-48cm. For some hikers, the fit may depend on your torso size more than gender. With an 18-inch torso, 38-inch chest, and 30-inch waist, I found the AC Lite 23 fits me well, even though I might wear a small or medium pack from other brands. Short story: Size it based on your torso, not gender.

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The Deuter AC Lite 23 daypack harness.
The Deuter AC Lite 23 daypack harness.

Deuter also offers the AC Lite packs in two different styles: top-loaders with a lid in the even-numbered packs (AC Lite 24 and 22 SL, $120) and panel access designs in the odd-numbered models (AC Lite 23 and 21 SL, $110). I chose the AC Lite 23 because I often prefer daypacks with one-step, single-zipper access to the main compartment to eliminate unnecessary steps because you might open it up multiple times on any dayhike.

These packs stand out most distinctively for Deuter’s Aircomfort harness and frame, which features a pronounced curve that creates enough separation to slip a fist in between the tensioned trampoline-style back panel and the back side of the pack bag. That’s about as much ventilation as you’ll find in a daypack, maximizing air flow over a sweaty back.

The design priority of maximum ventilation manifests in the AC Lite’s lumbar area—featuring a gap for air movement where many daypacks have a dense pad—the lightly padded shoulder straps, and the wide, nearly see-through mesh in the unpadded forward parts of the wide hipbelt. While the hot and humid days we hiked in the Presidentials would have left the back of my T-shirt and waist of my shorts quite wet from sweat, the AC Lite left me considerably cooler and allowed my next-to-skin layers to dry out at times of lesser exertion.

But the minimalist padding does not compromise on carrying comfort. I found the AC Lite 23 handled up to 20 pounds/9 kilos quite well, not shifting around even on the steepest trails and delivering enough comfort and stability for hauling at least that much weight (varying between people).

The frame’s elastic spring steel rods, crossing in an X shape between plastic framesheet pieces at top and bottom, allow a little flex while providing abundant rigidity that prevents a full load from overwhelming the frame—or the hiker. Two pads cushion the lower back on both sides of your spine (on either side of the lumbar gap) and attach to the lower framesheet and pack bag in a way that permits a bit of flex, dampening the pack bounce that can occur with some daypacks that hug your torso tightly.

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The 23 liters/1,404 cubic inches of capacity provide enough space for three-season dayhikes, while maintaining a moderate weight for a hiking daypack of two pounds, one ounce/920 grams (AC Lite 23). In the Presidential Range, I basically filled it starting out with my trail food for two days, more than two liters of water, various layers for a range of weather, a small DSLR camera and two lenses, and hut-specific items like a liner bag. The pack’s curved shape does compromise the ease of loading and unloading a bit when it’s full.

The long, front center zipper runs nearly the full length of the pack, exposing most of the contents from top to bottom; but with the pack filled to capacity, the increased tension on the fabric makes spreading the zipper opening widely for larger items like a jacket more difficult.

Notably in today’s hiking daypack universe, the four AC Lite packs have just three exterior pockets: one zippered top pocket for sunglasses and other small items and two stretch-mesh side pockets, one a drop-style that will hold a liter bottle, the other with a vertical zipper that you can reach while wearing the pack with a little arm twisting. The lack of hipbelt pockets—while definitely facilitating much better ventilation through the mesh fabric—may be missed by some hikers.

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Other than the light mesh fabric on the side pockets, the AC Lite packs are armored with fabric made from 600-denier polyester yarn and with a PU coating, giving them more durability than some of the top packs in this category.

Other features include a helmet holder ($20, sold separately) that attaches to docking loops on the front, a pole attachment on the front, and a sunglasses holder on the left shoulder strap. The pack’s internal sleeve accommodates a two-liter bladder and when it’s full; and that and the curved shape of the frame more noticeably eats into some of the main compartment’s capacity. It also lacks side compression straps, limiting options for attaching things to the outside.

Deuter AC Lite 23 and AC Lite 21 SL


The Verdict

With superior ventilation, comfort, and durability, plus good capacity and quick access, the Deuter AC Lite 23 and AC Lite 21 SL daypacks will appeal to many dayhikers and others who want a pack where comfort takes priority over lots of bells and whistles.



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See “The 10 Best Hiking Daypacks,” “5 Tips For Buying the Right Backpack” (which includes daypacks), and all reviews of hiking gear at The Big Outside.

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NOTE: I tested gear for Backpacker magazine for 20 years. At The Big Outside, I review only what I consider the best outdoor gear and apparel. See the Gear Reviews page at The Big Outside for categorized menus of all reviews and expert buying tips.

—Michael Lanza

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2 thoughts on “Review: Deuter AC Lite 23 and AC Lite 21 SL Daypacks”

  1. What a wonderful write up! Thank you. I am 5’9 with narrow hips (35 in) and my torso is 18.5 in. I’m am not sure if the Tempest or the Juno or Maya would better fit my body type. Guessing either 20 or 24L would work fine for my day hikes. Your thoughts? Also, durability and fit/comfort are very important to me. Thanks!

    • Thanks, Paige, and good question. Getting a good pack fit is always tricky. With non-adjustable daypacks, I usually find that the fit will be good on a torso length that falls roughly in the middle of the recommended fit range. With the AC Lite packs, your torso would fall near the upper end of the SL model’s fit range, which may not be ideal. The men’s model seems a better fit for your torso and maybe also for your narrow hips. But the Tempest and Maya have fit adjustability, which is often the best way to dial in comfort; and don’t rule out the men’s models in a pack if that seems like it’ll fit your torso best.

      Good luck!