E-wan, I've three seasons of experience with the Sinewave Revolution, which I'm happy to offer to you here. The "but" is that my experience may not be directly transferable to your situation -- but I'll let you judge that.
I ordered the Revolution charger when I spec'd my Raven in the autumn of 2013. The charger had been on the market for a couple of years before that, and I had read several positive reviews about it. It's readily available from the States -- I live in Ottawa, Canada, so I had the benefit of proximity, along with the disadvantage of the USD/CAD exchange rate.
Here's the summary of my experience:
1) First, my requirements: I wanted a power source for my headlight (a Trelock 40-lumens item) and for the charger. My headlight is mainly for conspicuity on grey/shady/misty/rainy rides and routes -- I rarely ride at night when I'm touring, so I don't need a headlight to show me the way. I use a couple of battery-powered tail lights. I also have modest requirements for recharging electronic devices -- a simple cellphone, occasionally my camera, and odds and ends like batts for my headlamp and (occasionally) my Garmin eTrex 20.
2) The circuitry: Sinewave included piggyback connectors in their kit, allowing the user to install two circuits from the hub. Following Danneaux' detailed guidelines on wiring his Nomad, I installed Deans connectors in both circuits, about 10 cms "upstream" from the hub. These allow me to (i) have a drip loop in the wires; and (ii) disconnect the wires at the Deans connectors, when I need to remove the front wheel, rather than tugging at the piggyback connectors where they mate with the tabs on the hub itself.
3) How it has worked in practice: No problem in getting the SON28 to power both the headlight and the charger, or one and not the other. Both worked as advertised. BUT, when both circuits were 'ON', the headlight had priority. This meant that on grey/shady/misty/rainy rides, the Sinewave was slow to charge even my modest devices. Travelling in Northern Europe in late Aug & early Sept 2014, for example, I had a few days like that. I rode all day with the headlight on, and as a result had to recharge my phone and batts from the mains at places where I stayed overnight. Not such a big problem, but that trip did show the limits of my setup. (Even less of a problem in Eastern Ontario, where I live, because in the summer at least, happily we rarely have more than one grey/shady/misty/rainy day at a time.)
(I did have a couple of other problems with my setup, but those were due to my less-than-expert soldering, and to a quality control problem with the headlamp -- no problems at all with either the SON28, or the Sinewave.)
4) This past spring, preparing for a trip in the western mountains June/July, where I figured I probably would have to deal with grey/shady/misty/rainy days, I changed my charging/lighting setup, as follows:
> I removed my Trelock headlight, and replaced it with a Cygolite item with a lithium-ion batt which is fed by a USB power cord. The Cygolite has a couple of powerful beams, and a nice flashing mode, which is what I use a on those grey/rainy/whatever days.
> I bought an Anker 2600 cache battery (a bargain at CAD 26!!) and hooked that up to my Sinewave charger during the day. (I had also bought a Y-shaped "splitter" USB cable, so that I could charge both the battery and a device like my phone or camera at the same time, if necessary.)
> This arrangement worked brilliantly well. I did have some grey/shady/misty/rainy sections, though happily, no full days of such weather. So, I used the Anker to recharge my phone, my Cygolite, or my camera overnight. Typically, I was recharging only one of those at a time, so the battery would usually do its work in less than an hour, and its charge would be run down by no more than 25%. During the day, the dynahub & Sinewave recharged the battery very quickly. Usually, if it was down 25%, it was full in no more than an hour or two. The one time I made heavier demands on the Anker, everything also worked fine: I lent it to the Kiwi I was riding with in the Canadian Rockies, and he recharged his Samsung tablet from about 30% to full in about 3 hours (and 30% to 80% in about 20 minutes!) I then recharged the battery in an afternoon's ride, mostly downhill from Bow Glacier Lake to Lake Louise, rather less than 4 hours' riding.
Hope that's helpful, E-wan, and good luck.
John
