How well do on-bike dynamos work? I'll be doing more, longer bikepacking trips this year and am intrigued by the prospects of charging the batteries on my iPhone, Wahoo and lights while riding.

The friends I have that use them like them a lot, especially those who splurged for the Sondelux hub. Note that most all dynamos require a converter to charge other devices.

They work quite well for commuting.

For charging other devices while bikepacking, I suspect they'd work well while going downhill. Note that most don't start putting out significant current below 6-10 miles per hour. How fast do you climb gnarly single-track?

When it comes to questions like this Alee is the source.

CyclingAboujt Dynamo Lights

I love my two dynamos they are super awesome. Having lights all the time powered by your movement is freakin cool and on my touring bike I do have a Sinewave Reactor but truth be told I haven't actually ridden that bike as much as I would like recently since I got the Sinewave working so I haven't used that as much but the lighting is awesome. If I had to spec again I would probably have gone with the Cinq Plug V with the integrated battery bank which makes more sense for modern devices but I could get the Sinewave at the time and it looks good and is well made for sure.

I would probably do a dynamo on most of my bikes if I didn't;t have so gosh darn many of them and some I don't really ride at night that often. Currently using a SON hub and a Shutter Precision (my first dynamo) and both are great but of course the SON is the top of the top so it is hard to beat.

Don't expect too much. When you navigate with a phone, the dynamo stalls the drain of the phone's battery, but does not eliminate it. When the screen is off, yes, you charge it, but slowly. The dynamos are designed to provide 0.5A at 6V or 3W. With the 5V of USB this will transcribe onto 0.6A. A slow USB charger provides 0.5A and a fast one 2A. I.e., you have a slow charger with a single output at hand.

In the Touring subforum there is a write-up of the Pedalcell rim dynamo. As I have been looking for a better way to charge a device while riding this caught my eye. Seems the thing has very good output and very low drag. Certainly a lower cost option than building a wheel around a hub, plus higher output to boot. Something to consider.

https://pedalcell.com/collections/frontpage

I'll make sure all my bikepacking trips are all downhill!