Good dynamo solution for 100+ miles
 

Hi all, first time posting--so that means I'm still reading the archives looking for previous questions :)

My son and I are training for the BP MS150 from Houston to Austin next year. It's a 2-day, 170 mile trip.

I'm looking for a good way to keep an iPhone running. It's running a wahoo app that works as a gps and cycle "computer". I'd also like some tunes.
I've got a small tray on the back of my bike where a bag slides in, but I have some room to mount elsewhere. It's a Scatante DX 350, so the cabling is on the top of the top tube.

So, I guess there are these questions:

1. battery pack + USB to phone or just dynamo straight to phone? (is that latter even possible?)
2. size of dynamo? It's an iPhone so it's abound to be doing about 5V DC at very small amps.
3. hub or external friction?

I don't do all-weather riding, so the top-end for durability isn't necessary--save what would be needed for a ride like this.

Thanks in advance for any considerations.

May be leave it off most of the time, ?? then the hub dynamo and current conversion pieces
like sinewave, makes,
for going from the hub output to a compatible output for USB,
to trickle charge the phone, can keep up.

generators for bikes have been 6v3w for decades, now they put out AC
so you need a rectifier and limiter circuit.. to go to USB standard.

yout tires will probably not have a utility casing ..
for the sidewall traction band for a bottle dynamo..




..

Hi [MENTION=485346]Dornier[/MENTION]. Charging from a dynamo isn't as simple as it sounds. To do it well, it's expensive and probably not worth your while if you don't do stuff like this often. I have a dynamo hub on a couple of my bikes, and I use it to run my lights whenever I ride (day or night) but I don't use it for charging. I usually run a GPS app on my phone when I ride, and to keep the battery from discharging, I use an external battery. I use the Anker Astro E1, which is small, light, and inexpensive. I can take a six hour ride and keep the screen on the whole time, along with a GPS app and a music playing app. At the end of the ride, the external battery is mostly discharged, and my phone battery is still at 100%. If you think this isn't enough, you can bring two batteries.

If you're still interested in dynamos, a hub is best for most people. The drag is a lot lower than the other types, and it's completely silent. The downsides are extra weight and extra cost.

Thanks Noglider.

I was considering that too--second battery. it'll handle nearly 20 charges of a phone. we're talking 10+ hours on day 1 depending on how we do. Having a second batt in the pouch with a usb cord would be pretty easy too. and cheaper.

I just use external batteries. My rides last up to 4 days, and sometimes the overnights are not that long. So far the batteries have worked fine.

For trips of only a few days, or even much longer if occasional access to outlets is available, I'd recommend just using a high capacity battery. Much simpler, cheaper, and reliable than combining a smaller battery with a dynamo.

Sidewall generators are noisy. Even if they do not slow you down much, you will think they are slowing you down. Not sure if that many miles would destroy the tire from rubbing on the sidewall generatr or not. In other words a dynohub is likely the solution if you do not do the big battery thing.

Sum of:Or, buy a couple power banks that cost a lot less. Run your phone with minimal backlighting, screen off most of the time, any apps not needed turned off, airplane mode to minimize power use, etc.

Not only is a dynamo overkill for the purpose, it doesn't necessarily even work at charging. The $30 rectifiers are problematic. Some phones won't accept a charge from them because the voltage varies so much.

I'm a huge fan of hub dynamos, but this is not the right tool for this particular job.

+1
I have two dynamo wheelsets for one bike, and I plan on building another for my folding bike, and maybe one for my wife's bike. But I use my hubs all the time for lights, and I use them occasionally for powering my electronics if I'm going to be off the grid for an extended period of time. But for an overnight trip, just get a good battery.

On the Tour Divide now a british guys Di2 went out and he has been riding single speed for two days. A first guess might be charging it from the hub dynamo. No diagnosed yet.

First off, great job hanging out with your son. Way to go Dad!

The setup I'm getting ready to use is like many have suggested, but there's another consideration. My battery back-up can recharge the iPhone 8+ a couple of times. I stash it in the under-seat bag with the cable zip-locked up to the phone holder on the bars. The iPhone itself is set to "low power mode" with the screen on minimum brightness and the auto screen
lock set to 1 minute. The fully charged iPhone has lasted over 2 1/2 hours on its own, so I expect to be able to get thru my first century ride with no power issues. During our rides, while i'm drafting as much as possible, I'm only interested in "time" and "averages" and I only check on those every so often. The combination of a battery and iPhone settings seems to do the trick.

After just 2 years a friend got a almost new* phone.. much better battery run time,
batteries and technology get old fast

and IT has put planned obsolescence into high speed


* 'NE yankee' cheap , not the up to the minute latest but what it replaced , just 1 model/generation ago.

fwiw - got this on my wish list

Elzle Solar Charger
https://www.amazon.com/dp/B077ZWCM8B/?coliid=I1PMFS28JVCOQ5&colid=AN82XFURGNTS&psc=0&ref_=lv_ov_lig_dp_it

& just saw this in another thread
https://www.adafruit.com/product/14

or one that takes (4) AAs
https://www.amazon.com/Verbatim-Powe.../dp/B007MLHS2S

That solar charger looks like a lot of crap that I bought directly from China and that disappointed me. On the other hand, the Adafruit and Verbatim products are good ideas if you think you'll need to buy generic cells on the road.

I wonder if there would be a way to directly charge an iphone's wireless charging off of a bicycle wheel.

I.E. Mount a bunch of opposite pole magnets on the spokes, then mount the iphone down near the spoke magnets.

Of course, you wouldn't have access to the phone when in motion.

What kind of facilities are you staying overnight in?

For a long day and a half ride, I'd probably just carry an auxiliary battery. Maybe use a separate ipod for the tunes.

The dynamo would be a better solution if you're regularly doing tours or night commuting.

[MENTION=392454]CliffordK[/MENTION], please read the thread. We made suggestions for him which he says he will use.

Yep... I have a similar solar charger.

It works fine as a high capacity auxiliary battery, but the solar charging capacity is worthless.

One issue that is a bit annoying with it is that it has an auto-off function. A good idea, but it causes problems with float charging from the battery pack.

There may be some larger (fold out) solar chargers that would work, but they need good noon sun exposure.

Well, we might go with the campgrounds--in which case I'm guessing charging is sketchy at best. But, the family will most likely pick us up at scoot to a motel that's farther away than most folks could get without a car. If it's the latter, then I'm leaning toward two battery backups.

thanks for the feedback. is it a bad concept or bad execution? meaning, is there a better one available? got me curious & found this article

https://thetrek.co/mailbag-how-do-i-...lachian-trail/

The concept is fine, but I'd bet it works poorly at charging, if at all. I think it needs more surface area, and with that, the price would be higher. Look at portable panels that get good reviews. They are bigger and expensiver. Because of cost and convenience, a solar panel rarely makes sense for cycling. Most of the time, we reach a power outlet frequently. Like dynamo charging systems, the use cases are special.

I just looked at the Amazon reviews. There is no account of someone taking it from discharged to charged using the solar panel. One person said the solar charging is useless. The satisfaction comes from the battery's large capacity. One review uses poor English and may be a shill.