Richard,
I'm so pleased you're looking into this topic, too. I figure if one of us misses something, the other will catch it, and we share similar interests about where we want to go with regard to on-bike gadget-charging, computers for biking, etc.
You wrote...
If I could afford it I would say a MacBook Air 11" (small light powerful).
<nods> Yes, I lingered by that display for some time yesterday, looking and even holding. The leading edge on them is thin enough to shave with. Very nice, but the power requirements worry me a bit, and the price is beyond my means. It does look like a very desirable option if those barriers can be overcome. A drool-worthy device!
Power for such a scenario (charging camera batteries, gadgets, MacBook Air) would require a descent solar panel and substantial battery...
Yes, solar is an appealing option 'cos it requires no additional work! I have not owned a solar panel, and my lack of direct experience has me wondering about the practical aspects:
1) A suitably high-capacity solar panel is rated at maximum output, under ideal conditions. How much power would be supplied on one of those flat-light, gray days, or when it is raining? Would there still be enough for a trickle-charge sufficient to make a difference or to directly power a device?
2) How best to array the panel while traveling? Atop the rear rack/rack-top load is the logical place, but what about angularity? There were many days in Nevada when I looked down and back in my eyeglasses mirror and saw a dark shadow in that same area (I was headed toward the sun at the time). How sensitive is the array to less-ideal positioning?
There is a man living by the river near me, who has an exceptionally large flexible-rollable solar array on his bicycle, used to power a boombox to ear-splitting levels. I would like to ask him about it, but he appears very antisocial and I'm not sure I could hear him over the noise (he has ignored the entreaties of path-users to turn it down). He had it perfectly aimed on a bright sunny day, and it looked to be producing power greater than I would need.
That would be ideal!
The two PowerTraveller batteries you mention Dan require mains adapter to charge, or have I missed something?
You sent me scrambling to check, Richard; a good thing! It appears the powermonkey extreme can be charged initially via mains power so you conveniently start with a full charge. It can also be charged via an available solar panel or via USB, according to
http://www.google.com/url?sa=t&rct=j&q=charge+powermonkey+extreme+via+usb&source=web&cd=8&ved=0CGkQFjAH&url=http%3A%2F%2Fwww.ecoark.co.uk%2Fdocuments%2F905.pdf&ei=qo9PT7vNEaOmiQK10bi0Bg&usg=AFQjCNEjgvzSY66jPsVmrap_kfS3rqgi4A&cad=rja which says...
The powermonkey extreme charger (1) can be charged using either the international mains charger (3)*, solar panel (2) or via USB (4) from an alternative power source (e.g. a computer or powergorilla, solargorilla, minigorilla product
This is an appealing setup, but apparently does not produce enough juice to power most netbooks. That would require the minigorilla, which does indeed require mains power or a solar panel. No mention is made of charging it via USB, and this makes the prospect appear dim:
http://www.brentozar.com/archive/2010/01/powertraveller-mini-gorilla-battery-review/ The lesson I am taking from all this is to read the specs and ad copy for all these devices carefully. Many can be read in several ways, and are often unclear so I go back a few times to check the claims. There have been some unfavorable reports about PowerTraveller products among tourists, but I am not sure if they reflect bad examples, or if the problems extend across entire product lines. See:
http://www.goingslowly.com/gear/Another solution would be a 12V dynamo
It has been done, Richard, but the results are somewhat mixed. Drag seems to be higher, partly as a result of the output and partly as a result of the generator used (it is hard to beat a present Schmidt or Shimano hub dynamo or the late LightSpin in the drag department). There are ways to extract 12 volts from a 6v dynohub (i.e. running two halogen headlights, as was popular with randonneurs for years), and the unregulated output of a dynamo increases with speed. At this point I think the (nominal) 6v solutions are the most mature and offer the greatest compatibility with USB output with a minimum of fuss. However, like you, I'd like
lots of available juice for my efforts. If some if good and more is better, too much is just enough!
I think the HyperJuice Mini looks good.
Me too! I have looked at it, and it certainly does have the power. One thing to keep in mind with such a small charging source (dynohub, solar panel) is the time-to-charge. A large-capacity buffer battery is terrific, and with a pass-through, it is possible to get a true buffer effect, with power being replaced as it is drawn off. The problem comes when one uses more than they can replace. Large-capacity batteries take a lonnnnnng time to charge from flat by our means (and apart from topping off via mains), so one can be without much reserve in the meantime.
My overall goal is to reduce the number of spare batteries I carry, and to keep power available to my gadgets. In the past, my mix of spare batteries and chargers weighed about 1.5kg -- a lot. And, once down, I had no way to recharge them except from rare mains sources. I did find it really paid to devote the last few days at home before departure to making sure the batteries were fully charged before leaving. The Tout Terrain The Plug 2 and the SON28 dynohub present a sea change for me, offering the possibility to recharge fewer batteries while away from the mains.
Apart from direct lighting, here is the direction I seem to be headed with my dynamo charging:
1) Use the Tout Terrain The Plug2 (TTTP2) to power my Garmin Oregon 400T GPS directly, relying on the internal AA cells (which cannot be charged in the GPS) for reserve power when stopped). As it happens, this won't occur often, as I generally use the GPS only sporadically to check my position, rather than running it continuously. However, there are times when it would be extremely handy to have it available continuously, so I am in-process on making a cable to allow it (the "State-named" Garmins require either a change of charging mode or a specially-wired cable to avoid going into data-transfer mode; I'm going with the cable and learning a bit about nonstandard USB wiring).
2) Use the TTT2 to top-off the embedded rechargeable batteries in my gadgets (cell phone, electric shaver, MP3 player).
3) Use the TTTP2 to charge AA/AAA cells to work as reserve power for my gadgets that use them (GPS, SteriPen, LED blinkys, LED headlight for camp use.
4) Use the TTTP2 to charge camera batteries (a special case for me and very problematic, as the chargers I have will need to be internally modified. I really want to charge my camera batteries, as shooting in HD video pulls them down very quickly, and I shoot a lot of stills every day as well).
5) Use the TTTP2 to top-off and maintain a level of charge in a buffer battery that would be used to power a netbook in camp for journaling, photo editing, and GPS track-transfer.
6) Use a solar array to supplement the TTTP2. To be honest, I can feel the drag of the SON28 when it is charging heavily and it would be nice to avoid that. I have thought about placing little flags on the wheels for wind-charging overnight in camp, but this has so far proven impractical (the bike has to be on its side; inverted would be better and I don't want to do that. Also, the charging SON28 requires an amazingly high effort to start it spinning from rest when it isn't being ridden. Once spinning, resistance drops due to magnetic hysteresis, but it is hard to start on its own...). The other problem comes from being in camp so little of the day. I basically start at first light, and by the time I stop for the night, it is nearly nighttime, and light levels are low. If I go solar, it has to be chargeable on the way.
The other problem I face that greatly complicates things is my extended time away from mains sources. If I stayed in a motel even once a week, I could top off a buffer battery and use that to tide me over, but I can't count on that. On the few times I've used formal lodging, I was grateful I remembered to pack a lamp-base-to-outlet adapter, as there weren't enough wall outlets in the room for all my AC chargers.
Keep the ideas coming! I'm surely interested to see how others would approach the problem!
Best,
Dan.
