I see these kits all over the place; are they any good? The sort of things, using either some sort of a spoke or even a hub attached to the wheel; that promise to charge your electronic devices. I'm getting into cycling, and one of my 'thoughts' going into this is that I'd really like the ability to keep my phone charged. Especially if I want to use my phone as a bike computer. There's a lot of inexpensive generator-chargers. Wonder if any of them work?

My other thought, was to mount a USB-chargeable battery in line with the generator. I.E., one of those smaller battery paks, that can charge from a USB source (as opposed to a 110V source), attached to one of these generators. And then the external battery, attached to my iPhone. My thought process is, the external battery pak becomes a buffer. And prevents the issue of potentially charging starting and stopping as I start and stop (or even slow down to a point potentially too slow for the generator to work).

Thoughts? Are those junk and a total waste? Or are there usable (and inexpensive) ones out there? If they are particularly expensive; then a dedicated bike computer seems like a better investment. But if there are good cheap ones, then the ability to charge my phone on the bike seems more versatile than just not using my phone and having a dedicated bike computer.

I think a lot of these devices work but remember one key concept, a bicycle generator only puts out 3 watts, do your own calculations here. There is a comprehensive article in Crazy Guy On A Bike that helped me sort through this. crazyguyonabike.com: Bicycle Touring: Solar battery charging for long tours, by Wayne Estes. And no, I have not purchased anything yet.
R

There's a few out there that don't work well, and some that do. I hear good things about sinewave. It will deliver 5W from a dynamo hub. Yes charging a battery pack is the safest bet. You can also get battery packs that will charge while powering your device at the same time (a lot don't do this).

Sinewave Cycles Revolution | Sinewave Cycles

Not clear to me what the OP wants to do. Is this for touring with camping, or homeless living? Work, school, home all have outlets to charge a phone after 4-8 hours riding.

If the bike computer keeps tab of how fast and how far you ride, a bike computer can be had for $30.

If you want help finding your way, you're probably looking at $200 or up for a GPS with routing.

The reputable USB charging solutions run about $100, on top of a $200 wheel with a dyno hub or a $30 stay-mounted generator. A spare charger for your phone costs, what, $20?

The OP just wants to learn. I'm curious, new to this, and intrigued by the prospect of charging devices while riding. The reality is, an external battery pak is all I can imagine I'll ever need. But I was intrigued when I saw those and thought "I wonder how well those would work if I rigged something up like that".

When I mentioned a dedicated bike computer; I was referring to something like a Garmin 810. Something that will record rides, offer routing, keep track of altitude, distance, speed, etc. And log everything nicely. Although that's all down the road. My iPhone will do most of that anyway, for now.

I actually did find a few cheapie bottle dynamos that reviews said (slowly) charged smartphones, or at least staved off battery loss. Although it seems like more trouble than it's worth; I think it's a cool concept. Which is why I asked! That way I might learn something.

No personal experience, but I've read favorable comments on the E-WERK by Busch & Müller, as seen here at Peter White and here auf Deutsch at Busch & Müller and here in English in their PDF catalog (pp. 22-23). Peter White hosts the manual here. It's not cheap. If it's too pricey for your situation, at least the information might provide some perspective on the technology and challenges.

Yeah, you can get a dynamo hub that will produce electricity. It's output is fairly limited - it can charge a phone no problem, but some tablets require to much power.

Usually dynamo's are used for generating power for a bike light at night, if you spend all the money on a dynamo I'd also buy a light to go with it. 15 years ago dynamo light was crap, but then they invented LED's which required far less power and made shaped-beam lights which use the light efficiently (among a number of other things).

Ixon Iq Premium - good light, $110 or so.
Schmidt Edelux II - same light at the iq premium, but slightly brighter and with an led with a nicer color temperature.
Luxos U - both a light and has a built in usb charger. Can only realistically run one or the other, but it's all in one unit. Drawbacks are it's size (it's kinda huge), some people feel it has a slightly worse beam pattern than the previous 2 lights, and it's expensive, though the cost is the same as buying a light + charger accesory.

I mean it all gets pretty expensive, an external battery pack is much cheaper. I have a dynamo light though because the freedom of always have a light on my bike and never ever worrying about headlight battery life was worth it for me.

A bottle dynamo will produce a lot of drag while charging, and won't do a great job. A dynamo hub will be more efficient, but still not sure it would be effective in charging something although I've never tried it myself. When it takes 8 hours to charge my iPad plugged into the wall, I'd say that the low power produced by a dynamo isn't enough.

Thanks guys! Lots of great info. Even if a hub would stave off battery loss I could see it being pretty useful. Though, it really seems like a battery pack is much more the way to go.

It's a classic cost vs convenience vs utility cluster!@#!. Lol.

If you have unlimited money and want to charge a phone, the dynamo is definitely the way to go.

Agree!
R&J

:-)

Has anyone seen a prototype of the Siva Atom? I am thinking about one of those for myself. Should be shipping soon.