Originally Posted by billridesbikes

I think plug5+ with an in-line battery would be my preferred solution for charging from a dynamo hub as long as you have a 1 & 1/8 steerer tube. It has an always ‘on’ and load detection so it stops charging when your lights switch off. Haven’t looked at a comparison in a while, but I believe it has higher charging at lower speed than the werk.

Plug5

Originally Posted by ChrisAlbertson

I have a USB current meter that is something like one of these
https://www.amazon.com/USB-Charger-Doctor-line-Voltage/

Bottom line is that a 500 ma charger is weak but you will have two of them and you can cut your power use. I'd run experiments at home for a few weeks and the USB meter can be informative.

Originally Posted by polyphrast

Here is a nice overview about dynamo power harvester (like the E-Werk). In case you need more power, take a look at pedalcell.com (But don't forget that you'll have at least considerably more drag with that system, even if it has an efficiency of 60-65%)

Regarding hub dynos: All better dyno hubs are solid enough to use full time. In case you don't want to spent time of rebuilding your wheel (or you don't want to pay someone for this), take a look at the velogical rim dynamo (here and here are some english reviews). Those are not cheap, but you don't need a new wheel, and they are as good as modern hub dynos. If you order them from outside the EU, you can deduct 19% VAT tax from the price (and have to consider duty/import taxes). There are different versions, one for slower travel (and higher power output), one for lower drag (and less power)

40 lux is imo a bit too less brightness, unless you drive in complete darkness (without ambient street lights or car lights)