Question on Dynamo hub
- toolonglegs
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Question on Dynamo hub
Postby toolonglegs » Mon Jan 11, 2021 8:17 am
Thinking of ordering a Son hub to fit to 29’er wheels. Plan is to let it charge a power pack during the day ( to recharge iPhone, GPS and head lamp ) and let it run light at night.
Is this feasible? Be on a MTB on at times a very hilly off road route, so at times won’t be moving fast. Aiming for 175 kms per day, about 13 days in total.
Any advise and setups would be appreciated.
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Re: Question on Dynamo hub
Postby RonK » Mon Jan 11, 2021 8:54 am
This is the best approach because many devices such as phones do not charge when the voltage drops at lower speeds but the power pack will keep charging as long as there is output from the dynamo hub.
I run the light during the day as well but the Beacon prioritises charging when the power pack is connected to the charging circuit.
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Re: Question on Dynamo hub
Postby ironhanglider » Mon Jan 11, 2021 9:10 am
Cheers,
Cameron
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Re: Question on Dynamo hub
Postby Tim » Mon Jan 11, 2021 10:47 am
To recharge devices you'll need a rectifier to convert to DC, most likely 5V/0.5-1.0A, equivalent to standard USB charging.
Lights such as Ron's do this for you. In my case I use an E-Work converter to charge a power pack then recharge the phone and GPS later.
https://www.sjscycles.co.uk/dynamos/bus ... k/?geoc=AU
This thread is dated but still reasonably current.
https://www.bicycles.net.au/forums/view ... amo+device
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Re: Question on Dynamo hub
Postby Aushiker » Mon Jan 11, 2021 12:48 pm
I also turn off the lights so the dynamo is focused 100% on charging my battery.
My interface is an early prototype of what is now the K-Lite DUAL USB charger. See https://www.klite.com.au/product-page/k ... v2-charger
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- toolonglegs
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Re: Question on Dynamo hub
Postby toolonglegs » Mon Jan 11, 2021 4:05 pm
From what I understand you need to be careful on what battery packs you buy? Need one with “through” power. Able to charge and be charged at the same time? Also better to have two smaller capacity ones than trying to charge one big one?
Still in planning stages so have plenty of time.
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Re: Question on Dynamo hub
Postby robbo mcs » Mon Jan 11, 2021 8:01 pm
https://www.cyclingabout.com/
here is the section on dynamos and charging
https://www.cyclingabout.com/category/e ... nt/dynamo/
this will answer all the questions you have, and many questions you haven't yet thought of
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Re: Question on Dynamo hub
Postby RonK » Mon Jan 11, 2021 11:52 pm
Yes, It's best to use a power pack with pass-through charging capability. This lets you connect the power pack to the charger and your device to the power pack, so the device will continue to charge even when your speed is low. I use a xiaomi mi power bank.toolonglegs wrote: ↑Mon Jan 11, 2021 4:05 pmThanks guys. I was thinking of using a Sinewave Revolution to convert AC/DC but what your saying Ron gives me food for thought. I won’t need to run the light during the day as I will be 80% off road or on very small roads. Like Andrew says my speed will be very slow at times but hopefully 50% of my day will be quicker.
From what I understand you need to be careful on what battery packs you buy? Need one with “through” power. Able to charge and be charged at the same time? Also better to have two smaller capacity ones than trying to charge one big one?
Still in planning stages so have plenty of time.
Of course it's a good idea to take any opportunity to charge using mains power. So I have an Anker 6-port charger. This lets me charge all my devices - power pack, phone, camera, bike computer from one power point.
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Re: Question on Dynamo hub
Postby Cycleops70 » Tue Jan 12, 2021 12:28 am
I've only managed 1 bikepacking trip so far, but a few rides on it on a Sunday morning.
It's a son28 with sinewave beacon light, & a small rear light (can't remember what make).
I charge my phone with a small power bank in line with the output as a kind of buffer. Seems to work quite well.
You might find off road you can't generate enough at lower speeds to make it viable. Particularly with larger wheels like a 29er.
My use is predominantly road, but I did use in on a section of the Munda Biddi & the light was good enough to see where I was going.
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Re: Question on Dynamo hub
Postby toolonglegs » Tue Jan 12, 2021 1:44 am
Pretty sure a lot of the time my speeds will be too slow to charge but the main ride is in August so my days will be long here, at least 14 hours daylight. Not sure how much I will need the light each night, but will be good to have the option to push on into the dark if I feel up to it. I am planning on a hotel every three or four nights so will be able to charge everything to 100 percent reasonably often.
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Re: Question on Dynamo hub
Postby toolonglegs » Sat Feb 13, 2021 3:29 am
- Jante DT SWISS XM421 29er 32T
- Moyeu SON 28 110x15mm Noir 6T
- Moyeu AR DT SWISS 350 148/12
- Rayons Sapim Strong
Thinking I will run Maxxis Ikon 2.35’s ... actually have thought about running 2.6’s but I haven’t got room in the back.
I have read that even with a Son28 I maybe struggling to charge the battery during the day as average speeds can be pretty low especially in the 2nd half of the route. But if they can run my lights ( haven’t 100% decided on them yet ) I will be happy.
I will run a helmet lamp as well which on low power should do me at least 3 nights on the trot. Maybe a hotel or two along the route to top everything up to 100%
I don’t know if I am even capable of doing this yet mentally / physically but I am aiming for 12 days max. Still 6 months off but having watched my little sis prepare for the Tour Aeoteroa I realize how quickly 6 months can pass!
I have no hols apart from this week until August so testing things once it warms up will require innovation!
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Re: Question on Dynamo hub
Postby RonK » Sat Feb 13, 2021 7:36 am
I suggest you consider also Vittoria Mezcals - I have them on two bikes, they are an excellent fast-rolling all-rounder for mixed surfaces. And it's not uncommon to run a wider front tyre so you could run a 2.6/2.35 combination if you prefer.
My personal choice for a long ride such as you are planning is for 29x2.1 Mezcals - wider tyres are heavier and harder to push so better not to choose bigger than really needed.
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Re: Question on Dynamo hub
Postby find_bruce » Sat Feb 13, 2021 10:36 am
As for speed, a hub dynamos produces what is effectively a constant current (~0.5A) however the voltage they can produce increases with speed. Dynamos have a very funky characteristic referred to as load matching. At a particular load for a given speed you can get a dynamo to produce way more than 0.5A - almost double. At slow speeds there is a limit to how much you can achieve.
The easiest way to get a low speed boost is the Forumslader V5. (How good is your german?)
Aushiker refers to power sharply dropping off below 15 km/h - the forumslader gets you that power at around 10 or 11 km/h, but as you can see from these graphs you're still not getting much power below that.
via List of Hub Dynamo USB Chargers and Charging Systems for Electronic Devices
- toolonglegs
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Re: Question on Dynamo hub
Postby toolonglegs » Sun Feb 14, 2021 12:51 am
As to the Forumslader Bruce... is that a USB buffer battery? Aim was to run a setup like Ron suggest before. But I am only organizing the wheel so far. Was thinking maybe a Sinewave into a battery.
I have no idea of my average speed while riding. Hoping for at least 15km av... which probably means a lot of time under 10 when climbing / pushing. I should have a least 14 hours daylight each day... hoping 11-12 hours ride time during daylight hours will be enough to keep everything charged even at the a lower average.
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Re: Question on Dynamo hub
Postby RonK » Sun Feb 14, 2021 8:18 am
I have 2.1 Mecals on my bikepacking bike and 2.6 Mecals on my MTB. I've been running them mounted tubeless for several years, yet to get a puncture or any other problem.
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Re: Question on Dynamo hub
Postby find_bruce » Sun Feb 14, 2021 5:25 pm
Sinewave is a good product - it generates 2.5w at 17kph. The forumslader is a bit more "bloke in a shed" build than others, but you can get it with a buffer battery (2100 mAh). The reason I suggested it is that it generates 2.5w @13 kph & should help make sure everything gets charged.toolonglegs wrote: ↑Sun Feb 14, 2021 12:51 amAs to the Forumslader Bruce... is that a USB buffer battery? Aim was to run a setup like Ron suggest before. But I am only organizing the wheel so far. Was thinking maybe a Sinewave into a battery.
I have no idea of my average speed while riding. Hoping for at least 15km av... which probably means a lot of time under 10 when climbing / pushing. I should have a least 14 hours daylight each day... hoping 11-12 hours ride time during daylight hours will be enough to keep everything charged even at the a lower average.
The headtube & top cap version looks neat when installed
,
The hidden electronics
(image from Rodgerbiltit in this thread
If you get the handlebar bag, at €110 instead of €227, you get
The three purple cylinders are the batteries,
The sinewave revolution is a much more professional looking package
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Re: Question on Dynamo hub
Postby Aushiker » Sun Feb 14, 2021 6:50 pm
This is very interesting Bruce. Off to look into the forumslader. If my translation/reading is correct, you need to put this together yourself. Also, I could not find any purchasing options. Does anyone have more specific details?find_bruce wrote: ↑Sat Feb 13, 2021 10:36 amAushiker refers to power sharply dropping off below 15 km/h - the forumslader gets you that power at around 10 or 11 km/h, but as you can see from these graphs you're still not getting much power below that.
Edit: Found the price list at http://www.forumslader.de/fileadmin/use ... nglish.pdf
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Re: Question on Dynamo hub
Postby find_bruce » Sun Feb 14, 2021 8:30 pm
They used to only come in kit form, but he will also assemble it for you - for what looks like a fairly modest fee of course - the downside is that it looks like it adds 3 months to the availability. The price list is dated 2017 so I'm not sure if it is current. I believe ordering is via email: info ((AT)) forumslader (dot) de so that would be the best way to confirm current prices etcAushiker wrote: ↑Sun Feb 14, 2021 6:50 pmThis is very interesting Bruce. Off to look into the forumslader. If my translation/reading is correct, you need to put this together yourself. Also, I could not find any purchasing options. Does anyone have more specific details?find_bruce wrote: ↑Sat Feb 13, 2021 10:36 amAushiker refers to power sharply dropping off below 15 km/h - the forumslader gets you that power at around 10 or 11 km/h, but as you can see from these graphs you're still not getting much power below that.
Edit: Found the price list at http://www.forumslader.de/fileadmin/use ... nglish.pdf
I don't own one, but I like the design because of its low speed boost. I know TrevTassie has owned one for a few years now, so he can probably point you in the right direction
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Re: Question on Dynamo hub
Postby toolonglegs » Sun Feb 14, 2021 8:53 pm
Thanks Ron, I will look into them... I know I have a habit ( love ) of bombing techie downhill sections, will have to reign that in as I also have a habit of damaging sidewalls!
So much new stuff to figure out!
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Re: Question on Dynamo hub
Postby find_bruce » Sun Feb 14, 2021 10:06 pm
Iphones are somewhere between 7-15 watt hours, so if your phone was completely flat, you would need to ride for 2.8 to 6 hours (AT) 2.5A to fully charge. Most GPS unit use less than 500 mAh, so maybe 1.5 hour. No idea about your particular headlamp, but I'm guessing around 3 hours if completely flat. Worst case scenario would be something like 10.5 hours.
BUT - if you're on the bike for 11-12 hours you're unlikely to have flattened your phone - when they talk of a phone having an 11 hour battery life, that's with the screen on, loading a web page every 30 secs. Similarly you probably won't be staying up late reading.
Plus it's really speed dependent - anytime you are doing 20km/h or more, you're looking at more than 5w with a forumslader, so basically halve those times
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Re: Question on Dynamo hub
Postby Aushiker » Sun Feb 14, 2021 10:18 pm
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Re: Question on Dynamo hub
Postby RonK » Sun Feb 14, 2021 11:12 pm
The problem with charging the iPhone is that its charging circuitry senses when the current drops and disconnects - this is to protect the phone from accidental discharge if you happen to plug it in to an unpowered USB port. It won't resume charging until the input stabilises, so when your speed is fluctuating close to the threshold it won't charge much at all. This why you need a power pack with pass through charging - to keep the iPhone charging continuously. In practice it's usually better to charge only the power pack then use it to recharge your devices once stop for the night.toolonglegs wrote: ↑Sun Feb 14, 2021 8:53 pmGetting to 2,5w at 13 instead of 17 makes it very interesting! Stupid question but at aforementioned 2,5w how long do you have to ride at the corresponding speed to charge everything? I expect to have GPS ( plus a spare ) ... iPhone and head lamp.
Thanks Ron, I will look into them... I know I have a habit ( love ) of bombing techie downhill sections, will have to reign that in as I also have a habit of damaging sidewalls!
So much new stuff to figure out!
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Re: Question on Dynamo hub
Postby Aushiker » Sun Feb 14, 2021 11:21 pm
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Re: Question on Dynamo hub
Postby toolonglegs » Mon Feb 15, 2021 6:37 am
Head torch I am thinking Supernova Airstream 2... should get 2 to 3 nights out of that on low power.
GPS will probably be a 1030+ ... the track can be tricky, looking at previous years traces there can be a lot of hunting around for the correct route. Organizers are really strict with penalties.
25mm internal width rims should be good I hope!
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Re: Question on Dynamo hub
Postby Aushiker » Mon Feb 15, 2021 11:19 am
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