Almost too much sunshine in Serbia, Andre. Temperatures on the road peaked at 51°C ( officially 44°C ambient according to Serbian radio in the town I rode through) and went through better than 8 liters of fluid/day. Yes, it made the solar panel very happy.
The little Joos Orange solar panel with 5400 mAh accumulator battery stayed charged in the sun very nicely. It still charged on cloudy days and in the wet (It is submersible). On sunny days, it took a full 12 hours to charge from completely flat to completely full. I have a second one at home and wish I had brought it as well so I could have swapped off between the two. I lacked the ultimate capacity I would have hoped for in my very heavy, high demand smartphone use. For more ordinary needs in generally good weather, I think it would have been fine.
The Golden rule that applies here is to refill the solar charger in daytime and use it only at night to recharge gadgets. Otherwise, one quickly falls behind the curve.
In this case, I used the Joos Orange as a fallback option, partly for time and partly for capacity. My Samsung Galaxy S4 smartphone uses a 2.0A quick charger and that takes the 2700mAh battery from flat to full in a bit over two hours. The Joos Orange has a standard USB 2.0 output of 5vdc @ 500mAh, so it takes 4x longer to charge than the Samsung 2.0A mains - powered quick charger.
I also brought an Anker 20,000 mAh storage battery with 3 USB "smart" charging ports that sense and supply current at the maximum charging rate allowed by the device. I found results with it did indeed match the dedicated Samsung mains quick charger. Figuring losses (the Anker unit is high efficiency as these things go at ~73%), I can charge the phone just under 6 times with it, and as fast as usual.
I also took a spare, fully charged 2600 mAh phone battery for a quick swap when/as needed. I've used the phone heavily on this trip including for non continuous navigation and for journaling with html output and photo/video editing so my demands were greater than usual.
Yes, on days with consistent full sun in most practical use of my smartphone, I could have gotten by on the Joos alone and gone outlet free, even though I didn't choose to do so. In more typical weather and my typical use, I do think I'd want to take my second Joos Orange to be truly independent of mains power in mostly good weather. I think more frugal use and consistent good weather would allow one to do this with a single Joos unit, but not under high demand as in my current phone use, and not if there were more cloudy or rainy days. Yes, the unit will still charge in those conditions and even in the tent in daytime, but the rate of charge is much slower. In periods of consistent rain and clouds, I found the time to fill to full from flat could double or treble.
Even the single panel has been a worthwhile carry for me at present given Andy's bike has no dynohub/charger. It has provided a most welcome backup margin. I think a single unit combined with a dynohub charger would allow true independence from mains power in most reasonable use and conditions...the unit itself can even be charged to ~87% from a dyno-charger on cloudy days. For expedition use, two Joos Orange units and a dynohub would do the trick in nearly all use and conditions, which is why I bought a second one for such use.
However, for maximum convenience and shortest charging times within a 5+ phone charge cycle, then it is awfully hard to beat the Anker storage battery (mine is the Cosmo 3 as I recall). It does require mains power to recharge and cannot be charged from solar, another battery, or USB sources including a dynohub-based charger.
The combo of spare charged phone battery, Joos Orange with built in 5400mAh accumulator battery and the Anker 20,000mAh storage battery has worked fine in greatly extending my independence from mains power but is not the ultimate solution for true indefinite independence on expeditions. For that -- and in largely non - winter weather, for my use (did I add enough qualifiers there?) -- I think my SON 28 dynohub and either TTP2+ or B&M e-werk for daytime powering/charging while riding plus two of the Joos Orange solar panels for nighttime recharging would allow for weather variability and do the trick, albeit at standard USB recharge rates. Add the Anker 20,000 storage unit and you'd be set to get through some extended patches of rough weather.
It is this true independence that causes expedition bikes to run so heavy. To no longer depend on the grid for power, taps or streams for water or shops for food, you've got to carry it with you. That weighs a lot but is really the only option in truly remote places with severe conditions unless you drive through and pre-cache stores of supplies...which kinda kills the thrill of exploring new areas the first time by bicycle. It also brings up the matter of stores spoilage and predation by bears and other animals.
All the best,
Dan.
