I'm surprised how many dyno users here say they can't feel the drag of the hub when it's charging. I've got a Son28 on one bike with a Sinewave Revolution converter on the stem. I noticed on my first tour with it that under a certain speed (~6mph IIRC) it would stop putting out enough power to charge my iphone. On long slow loaded climbs, I would hear the "charging initiated" chime over and over as my speed varied around the threshold. That seemed like bad news for the phone, so I got in the habit of unplugging it when climbing (the converter was ziptied to the stem, so this wasn't too fussy). The reduction in drag when unplugging the load was not subtle! It didn't take long to realize that the drag from the charging system was always there, even when the output was not high enough to trigger the phone charging cycle. Pretty annoying to have that extra drag and get nothing from it. So I spent a lot of brain cycles plugging and unplugging and kicking myself when I realized halfway up a mountain that I'd forgotten to unplug, and likewise forgotten to re-plug on a descent.

Next tour, I wired up a switch into the computer mount to connect and disconnect the hub from the converter and it was awesome. Flick on, flick off - I found I used it all the time. Sometimes I just wanted more speed on a descent, or to chase down some roadies after I'd ridden myself into top shape, and definitely on every climb. With a switch at your fingertips, the drag is very palpable. I mean, you can feel the ~3/4 seconds it takes for the converter to charge up and activate the output and trigger the charge on the load end; it's so obvious.

I guess if you plug it in, forget about it, and never try this kind of A/B ride test, it's just part of the background and you won't ever notice it. Maybe with squishy draggy tires, sitting bolt upright in the wind, never lubing the chain, rarely checking tire pressure, or any number of things we all do that make bikes slow - the relative drag of the hub is missed.

I don't think I would ever tour without the convenience of a dyno (got another pair of Son28 disc hubs I need to build into wheels for my newer bike and the GF's) but I would also never ride a tour without the switch, because it's great to have control. I purchased and built a Forumslader to use on the next tour, and I'm very curious what its increased charging rate and corresponding increased drag will feel like over time. With a switch on the hub input, 3x18650 battery cache, and tons of info in the highly detailed phone app I expect I can figure out how much of the time I'll need to run it for: phone, Garmin, front & rear USB rechargeable lights, airpods, etc.

PS: I haven't tried solar on a bike trip yet, but my experience in 2013 on a long trek in Ladakh with a small Goal Zero panel was not great. Best I could do with the panel on the backpack while hiking, and optimally placed in camp, was a slow net negative on my phone I used for music and ebooks at night at minimum screen brightness. Needed a heavier panel I guess.