I'm not sure if this link has been posted before, but it provides some interesting thoughts about power loss when riding with a hub dymano.
https://www.cyclingabout.com/how-much-do-hub-dynamos-really-slow-you-down/I think the article might help win sceptics over to the wonders of hub-dynamoism and also confirm to those who have already invested in such a hub that this reliable power source allowing lights to run 24/7 and/or USB devices to be charged with adapters does not cause major impact on how fast we are able to get from A-B in real world examples at various speeds and illustrating the actual speed loss in those varying circumstances from using such a hub.
"The most-efficient hub will slow you down:
10-30 seconds per hour with no lights or chargers attached
1-2 minutes per hour with a USB charger
1.5-2.5 minutes per hour with a bright light
The least-efficient hub will slow you down:
0.5-1 minute per hour with no lights or chargers attached
2.5-3 minutes per hour with a USB charger
2.5-4 minutes per hour with a bright light"Those riding with their Shimano entry level hubs with SON users on same ride both with lights on, you can be happy in the thought that if the SON rider arrives 1.5 minutes earlier than you at the next break stop that they can order at the window, and by the time you arrive the coffee is served and STILL HOT
