Abu Mahendra

So, who sells a kit that converts the output of a Schmidt dynamo hub to USB 5 volts DC?

John Lesar

I use one of these. Works well.

Sinewave Cycles

noglider 

Those look good, but I imagine the output gets pretty low when your speed decreases. If it can't provide 5V at 0.5A (or whatever your phone wants), does it just cut the output to zero? If so, does it resume output when input is sufficiently high? That could be annoying or even unacceptable, so it might be best to use it to charge an external battery. The trouble with those external batteries, however, is that they seem to be designed not to provide output while being charged.

corrado33

Wow those things are expensive. Especially since a rectifier chip + buck converter + voltage regulator + a few caps is on the order of a few dollars.

Makes me wonder if you could take any old cell phone charger and slightly modify it to deal with dynamos.

J.C. Koto

I think you're generally right but there was an old thread here on the ELG subforum where someone posted about a specific external battery that provided output while being charged, IIRC this battery was designed to be used with a solar charger but allowed charging from a dynamo/USB interface as well. I'll see if I can find it again...

e: This was the specific post I had in mind. Of course this is an old thread (older than I thought ) so maybe there are better batteries now.

Drew Eckhardt 

I use a Busch & Mueller USB-Werk with my SON28. It has a small (500maH) built-in cache battery so I don't get "external power supply lost" messages when stopped during the day time (at night with lights it usually works without interruption, but sometimes briefly loses power if the cache battery isn't fully charged). $54 from starbike. bike-discount.de should have similar prices, and has flat rate $22 shipping. Note that shipping may take 10 business days. Also note that's less than half what Peter White charges, and even with nothing else in the order like tires you're still getting a 40% discount.

That works great for a GPS (Garmin Edge 500 or 800) or Samsung S5 Galaxy in ultra low power mode - I get home with 99% battery on whichever was charging.

It does not provide a lot of current like you need with modern smart phones outside low power mode. Trying to power my Samsung S5 to use as a bike computer it runs the phone a little, drops power as the external battery discharges, charges a little, drops power. The result is reduced discharge rate, not recharging. In that case something like an E-Werk is needed, with external cache battery if you want continuous power when stopping.

Some of the other devices are very inefficient, don't come on at low speeds, etc. Most are much more expensive than when you import one of the B&M units from Germany.

dim

[h=1]Tout Terrain The Plug III[/h]
Review: Tout Terrain The Plug III - CyclingAbout CyclingAbout

Drew Eckhardt 

The original isn't very good electrically. No clue about the third try.

Google translated Future Bike USB power supply comparison

dim

I'm still searching as I too will be getting a Schmidt dynamo hub and light (I'm planning to do some Audex rides) ....so I need to be able to charge a satnav, mobile phone, Dinotte rear light etc

I spoke to my LBS and he recomended the Tout Terrain III .... from reviews that I have read, it seems to be pretty good (the new one) .. If I can find something better, even if it costs much more, I will pay the extra .... this will be a crucial element of my rides

I have 2 months to decide, and will be reading some recomendations on the Audex forums .... I have to get a few other things first

fietsbob

It's a crowded marketplace , PLus now, AxA & B&M include the USB converter within the Headlight.

the option of the extrawheel trailer means you can have 2 hub dynamos.


Adding: It Might be good to read up on all the Schmidt Hubs , they Now have produced some that are lower magnetic drag ,

but say the needs of LED lights being a smaller demand allows them to lower the output to just what the lights Need


To achieve that..


a 28 in a 20" wheel may be the way to go.. ..

Drew Eckhardt 

The B&M Luxos-U USB output reportedly turns off when the light is on, which may be bad when you're navigating by GPS on long days riding after dark on roads which are new to you.

Conversely, the stand alone units still have output.

noglider 

This excellent article led me to more excellent articles by that author. Thank you!

fietsbob

.. but still have to 'Rob Peter, to Pay Paul ' doubling the load wont increase the supply ..

either or... or light dims & charge rate slows a even smaller trickle.

no infinite improbability drive..

noglider 

Right, there's no free lunch, but efficiency improves over time because of innovations. Most hubs are rated at 3W, and I'm guessing they are designed to produce full power at fairly low speeds so they're useful for Joe Average. There is probably a niche market of people who want more power and can produce it easily since they typically go faster than Joe Average does. The obstacles are: 1. it's a niche demand so manufacturers have a small incentive to develop this, and 2. assumptions and designs have to change, such as the devices that connect to the power source (dynamo). At higher-than-average speeds, the hub probably produces a surplus of power, but few devices are designed to take advantage of that since it's a safe assumption that the abundance won't be there reliably.

It really is possible to make a dynamo-powered charging system that provides more than 6W. The question is whether the market would support it.

fietsbob

Extra wheel trailer can include a second Hub dynamo..

Or add a Bottle Dynamo Plus your hub dynamo... double the power sources as You want to double the power load.

Still have no Electronic toy addiction..

I toured into Eastern Europe with just a Map Of Poland I got from a fellow Passenger on the over night ferry from Copenhagen.

noglider 

Bully for you. You are telling the original poster that his question is invalid and his quest is useless.

I also toured before there were electronics that were useful to a bike tourist. Of course, I got along fine. If I had to do without electronics, I could manage fine, but I have a choice. If I choose to use them, it would only make sense to find gadgets that work well.

Drew Eckhardt 

Most hubs are rated at 3W into a 12 Ohm load at 15 km/h.

They're current sources, so they'll deliver more power into higher impedances and less into lower.

New SON28 output at 20 km/h increases from 3.2W into 12 Ohms to 4.5W into 24.

Speed increases current.

New SON28 output at 30km/h into 24 Ohms increases from 3.2W into 12 Ohms to 6W into 24.

Nearly all dynamos are built for the German market, which requires dynamo powered lights on all bikes weighing over 11kg. Consequently they're made to comply with the StVZO (much easier to type than Straßenverkehrszulassungsordnung which is one big German word for road traffic licensing regulations) rules on bicycle lighting.

noglider 

Drew, I read somewhere that the dynamo requirement was lifted in 2013 and that battery-powered lights are allowed. I guess that explains why B&M is now making some very nice battery lights.

The nice thing about the StVZO bike lights regulations is that good lights are mass produced and are reasonably priced, and they're available outside Germany.

fietsbob

MS in Electronics & computer science , I dont have, so I'll let those who do, finish this..

Chris Pringle

Just some notes on audax/brevet rides and the use of electronic devices:

1. You will need to think seriously and smartly about consolidating electronic devices. This is not so much of an issue for 200-300 Km rides, but the longer you go the more you will need to figure out ways to save energy while staying safe with some connectivity/communication. Take advantage of the power of the latest cell phone technology -- Phone, GPS, cycling computer, camera and more in one package. The newer cell phones are also more energy efficient. For the longer rides, audax riders usually carry handlebar bags. Throw a 20000 mAh power bank in there and you should be golden for a couple of days. Using a simple Cateye or similar computer is a always good idea. The batteries on those last up to a year.

2. For lighting, dynamo power will be your best friend - Get the best front and rear dynamo lights you can afford. Great and rapid advances in LED technology make it feasible to get really good illumination and safety with very low power input. Remember that lights in flashing mode are not allowed in brevets in order not to blind fellow riders. This makes you think even harder about lights, especially if they are battery-powered. Dynamo lights clearly become the big winners. But you will still need to carry some spare battery lights because no technology is fail-proof. No fun getting disqualified for technological reasons.

3. A dynamo is not a panacea for your energy-hungry devices. In fact, it is far from it. It is true that you can charge some devices with a dynamo hub while your lights are off. There is, however, a certain romanticism about being able to charge your electronic devices by simply pedaling, but the reality is that pedal power is very limited. In the end, most users feel somewhat disappointed when it comes to charging electronic devices with a dynamo.

VegasTriker

Seems like an expensive solution for what can be accomplished for just a few dollars using the newer Lithium polymer battery packs. The Plug III sells for $158-$171 online. It has a 500 mAh built in battery. That's not very large. I have one of the same 500 mAH capacity built into a tiny LED USB rechargeable 100 lumen taillight.

If you are willing to use international sellers you can buy a 3 ounce 5600 mAh universal battery pack for under $6 postpaid (Ebay item # 252099712013). Dimensions are 4.17" X 1.5" X .38" I have similar battery packs that I use to power LED lights and they are fantastic compared to the batteries I used just a few years ago. If you are on tour, a solar charging battery pack might fill the need - 20,000 mAh solar charged power bank $14.19. Not as compact or light as the first one ~5" X 3" X 5/8" and a little under 8 oz. (Ebay item # 261946804795) Some solutions are pretty elegant but they are too expensive to be practical.

If you are already a user of 18650 Li-ion batteries you can get a battery box that holds 4 batteries and produces 5V for $2.58 postpaid (eBay item # 371580608892). I switched to these batteries for my flashlights and some other uses. It's way cheaper than using throw-away batteries.

noglider 

I've used 18650 batteries, and I've bought inexpensive gadgets from Chinese web sites. Lately, I think I'm getting a better value buying from Amazon because of their customer service. Some of the items arrive shipped from Chinese makers, but that's fine. If I have a problem, Amazon responds quickly. If the originating vendor doesn't answer, Amazon gives me a refund anyway. A self-contained battery (which has cells such as 18650 sealed inside) cost only a little more and are more convenient to charge. They last about as long as 18650 cells, two to three years, so that's fine. I've gotten the small, medium, and large kind. They all serve a purpose.

dim

thanks Chris ... some interesting points and I will do a lot of research.

This is all new to me, so I have lots to learn. I am reading a forum with Audex riders (yacf.co.uk) and will join the forum shortly and post many questions

in the meantime, I have ordered the following which will come in very handy:
[h=1]RAVPower 26800mAh 3-Port 5.5A iSmart Output Portable Charger Compact Power Bank External Battery Pack for iPhone, iPad, Samsung and More - Black[/h]

J.C. Koto

FYI, as of this moment your link is going to a "UFOs, Conspiracy Theorists, Lunatic Fringe" forum, not even a particular post, just the list of threads. I don't know if that was your intention or if bikeforums is being sketchy with it's links again.

dim

lol .... i read that forum daily .... must of been my mistake

here is what I bought:

https://www.amazon.co.uk/RAVPower-26800mAh-Portable-Charger-External-Black/dp/B012V9H3WA