Dynamos and powering stuff

[composite]

I'm currently specing a bike that I'm building for 12, 24 and unsupported bikepacking type racing/riding. I got a load of stuff already but I'm still planning some parts for it.

I would like to go with a dynamo hub to power a light at night and a GPS in the day. Possibly other devices (phone) to but that's not important at this point.

So I need to get some things straight in my head.

I have been looking at the Exposure Revo. (http://www.exposurelights.com/product/2 ... %28new%29/) This gives you a hub and the light. I believe that the hub is the PD-8 (http://www.sp-dynamo.com/8seriesdynamo%20hub.html) is that right?

So there is a wire that comes out the hub up the fork and plugs directly into the light? Any idea what sort of plug this is? Can you switch the dynamo off to reduce drag when its not needed?

Would you need something like the Plug 2 between "the wire" and my Garmin Edge 800 to make it USB? What are the options for this?

I'm basically looking for a list of kit options to get to my end goal. I'm normally alright with this sort of stuff but I'm a bit confused about things this time. I'm not sure if I'm over complicating it in my head though.

[Mart]

I have done a bit of thinking on this very subject. I hope I can answer a few of the questions

HUB - Yes the Exposure hub is a rebranded SP-PD8 (I had email confirmation of this from Hope)
Hub output is 6V (more on htis later), and feels notchy spinning when you first get it but thats just the magnets inside. You cant feel it at all when your riding

Revo Light - comes with wire that goes from Hub to Light. This plugs directly into the light
The light does not have an Off Switch, but doesnt need one as you can just pull the wire out from the back of the light. There is a output plug on the light that could be used for a rear light.
Exposure website says the Revo is not suitable for USB duties via the booster cable, like their other lights

For further USB duties you need to have some sort of electronics between the Hub and USB. The hub produces 6v and the electronic gubbins are needed to step down the voltage to the USB standard 5v
There are several options here: search for
- Lightcharge
- Kemo
- Plug2
there are advantages and disadvantages for each of the options. I got to the follwing
Kemo - cheapest but not sure on how waterproof, wiring would be very exposed
lightcharge - looks waterprooof but not sure on how the switch arrangement would work as the Revo would not plug neatly into it (like it would the Hub
Plug 2 - Most expensive of the 3, but waterproof and much neater solution

I went for the Plug2+ (gives better outputs at lower speeds) and is wired in Parallel with the light
Its also very easy to install. I'm not the best at spannering and it took me less than half and hour
The Plug 2 was one of the few that would charge an iPhone/smartphone. This opens up options for navigation beyond just using a GPS. The Plug 2 only draws current when you plug something in

Sorry for the ramble. Hope this answers some of the Q's. Its not that complicated but I found I needed to think about how I wanted the set up to work for me and what equipment you already have and what you might need. Im a bit of a late starter with bikepacking so didnt have a lot of stuff to begin with. For me this set up also allows me to keep my options open in the future.

[Zippy]

I remember Rob on a thread previously mentioned that from the hub to power USB reliably, you can get something like one of these:

http://www.ebay.co.uk/itm/2600mAh-Exter ... 35c9c09026

[Mart]

For me that kind of defeats the purpose of going with the dynamo set up. ability to be lighter, and more self reliant, through not carrying batteries.
At the end of the day it depends on what you want (or need) your set up to do

Can you tell i've been converted Blame it on Mr Dean and his great ideas

[composite]

Thanks for that Mart, that's the info I was after. :D

I remembered this morning that Mike Hall was using a plug 2 so looked at his kit list again for the TD and he mentions about his power setup, which is actually exactly what I want. Not sure how this went out of my head... http://normallyaspiratedhuman.com/?p=1337

He does mention in the comments about how the plug 2 is wired up.

...you can just run two cables into the hub connector. Strip back the wires a bit, twist the pairs of ends together and insert and assemble into the connector as normal.

Is this how you set yours up Mart?

Could this not be done with the Lightcharge as well do you think, unplugging the GPS/Light as appropriate to only have one plugged in at a time but not have to keep unplugging at the dynamo end?

[Mart]

...you can just run two cables into the hub connector. Strip back the wires a bit, twist the pairs of ends together and insert and assemble into the connector as normal.

Is this how you set yours up Mart?

Could this not be done with the Lightcharge as well do you think, unplugging the GPS/Light as appropriate to only have one plugged in at a time but not have to keep unplugging at the dynamo end?

Yep - thats how I did it too - easy

I did consider the lightcharge, and is also a neat solution. As far as I can work out its a switch for USB or lights. It looks like you would run just run one wire from the hub to the switch and then connect in the light into the switch. I just wasnt very clear how the connection (Light to Switch) would work out

[ericrobo]

Have started researching this... advice welcome please...

conclusions reached so far are to go for an SP PD8 hub with an Exposure Light (+ rear light), and a Plug II to power GPS etc. I appreciate that there is a wire from the hub to the light, but what about the Plug ? Is that also connected to the hub ? (in other words are there 2 connection slots on the hub ?

How many devices can you power from the Plug ? (or how many connection slots)

Also would this setup allow running a Dakota 20 GPS - it takes 2 batteries so does that mean you would use the Plug to charge spare batteries and just run the Dakota off its batteries ?

How do you get the hub fitted ? Do you get a wheel builder to fit it ? Does it fit any wheel ? I have a Cannondale with a Lefty front fork... the wheels have 24 spokes - would it fit ?

Anyone recommend a shop/supplier who know what they are talking about ?

[chris n]

You can't get a dynamo to fit a Lefty. Closest thing is the SON XS-M, but the axles are different: http://www.nabendynamo.de/produkte/son_xs-m_en.html

[paul78]

Also worth looking at the K-Lite dynamo offering ..

https://www.facebook.com/kLite.com.au?fref=ts

They are currently making me a switching box with USB outputs and a battery pack for storage when GPS,Phone etc doesn't need charging.

I have an Exposure Revo but my life would of been easier if I had gone to K Lite first

[Ian]

I heard the other day that the SP hubs are non-serviceable. So when the bearings are worn, that's it, the hub's dead...

[Zippy]

I heard the other day that the SP hubs are non-serviceable. So when the bearings are worn, that's it, the hub's dead...

Sounds like a challenge

[Mart]

[quote="ericrobo"
SP PD8 hub with an Exposure Light (+ rear light), and a Plug II to power GPS etc.
I appreciate that there is a wire from the hub to the light, but what about the Plug ? Is that also connected to the hub ? (in other words are there 2 connection slots on the hub ?

How many devices can you power from the Plug ? (or how many connection slots)

Anyone recommend a shop/supplier who know what they are talking about ?[/quote]

Yes just twist the two wires together from the light and Plug and inset into the hub.
Hope you can see from these pictures





Plug has one slot, and has a 500 ma at 5V output so realistically its only one device at a time

Hubs are not user servicable, however SP say they will replace bearing Free of Charge if you send it back to them. Given you would need to probably disassemble the wheel to send hub away overseas and then wait until return, it could well be easier to just buy a new one. Not ideal

[Chew]

I've been thinking about this too.

I'm assuming you have to disconnect the electrics when you remove the front wheel?
How good is the seal on the electronics, assuming Yorkshire drizzle, grit and river crossings?

[ericrobo]

I phoned a shop yesterday to ask basic questions about dynamo hubs, the guy had been wheelbuilding for the last 8 or so years, and fitting dynamo hubs more recently... he said he fits about 10 a week (if I heard correctly, it seems alot). He said that the SP hubs were not good at all, they had some in stock but were not going to get anymore. The best ones were Son Schmidt BUT if you needed a repair it was a very long winded process, they had to be sent from their shop to a shop Bristol way (probably SJS Cycles), then from there sent back to Germany.

His hub of choice was the Shimano N80, because it was simple and repairable (but I don't think that one is for a disc hub ?)

[chris n]

I phoned a shop yesterday to ask basic questions about dynamo hubs, the guy had been wheelbuilding for the last 8 or so years, and fitting dynamo hubs more recently... he said he fits about 10 a week (if I heard correctly, it seems alot). He said that the SP hubs were not good at all, they had some in stock but were not going to get anymore. The best ones were Son Schmidt BUT if you needed a repair it was a very long winded process, they had to be sent from their shop to a shop Bristol way (probably SJS Cycles), then from there sent back to Germany.

His hub of choice was the Shimano N80, because it was simple and repairable (but I don't think that one is for a disc hub ?)

Yes, Schmidt hubs have to back to the importer (SJS) first.

Shimano DH-3D80 or DH-3D72 for discs. You can rebuild the bearings on one side of a Shimano hub yourself but it's not easy. The coil/axle assembly is available as a spare part from Shimano. Still won't fit your lefty though...

I'm assuming you have to disconnect the electrics when you remove the front wheel?
How good is the seal on the electronics, assuming Yorkshire drizzle, grit and river crossings?

Easy to disconnect for Schmidt (two spade terminals) and Shimano (a small plug). Not well sealed at all, but in practice it's no big deal. My old Shimano hub had been running on my winter bike for 6 years and around 10,000 miles with no corrosion or electrical issues.

[slowupslowdown-under]

I have an Exposure hub and light and it runs well (limited testing).

I also want it to power the GArmin 800 and, instead of the Plug - large out lay) got one of these for £25

http://www.kemo-electronic.de/en/House/ ... ini-B-.php

Can I work out how to wire it all up?? Can I buggery!

Some one please help before I try to fix it with a hammer!!!

[Ian]

I'm no expert, but it looks to me that the wiring instructions are printed on the case?

[Bearbonesnorm]

Some one please help before I try to fix it with a hammer!!!

Yep, I reckon this sums it up pretty well.

[slowupslowdown-under]

the only bit I get is the usb that goes into the garmin!

the other 3 wires (light, earth and dynamo) each have one wire. The contact on the hub has to ports. Do I split the wire to be in contact with both or just one?

Then the wire going to the light. The exposure light connects directly to the hub. So with the wire from the Kemo do I a) leave it hanging or b) put it in the port of the light with the 'propoer' wire from the dynamo hub

Earth wire? I have a carbon frame!

[Ian]

Numbering the cables on the box left to right: 1) USB, 2) earth, 3) light, 4) hub.
The fifth cable goes direct from the hub to the light. Your little black box is a switch that directs current either to your USB device, or the light. All current from the hub must pass through it.

You need to have a cable 5 going from the hub to the light, and a cable 4 from the other contact at the hub back to the switch. Cable 3 goes back to your light to complete the circuit when the switch is in the light position. The earth cable 2 could be attached to a fork, or anything that acts as a conductor will do.

Simples.

[slowupslowdown-under]

FIFTH CABLE??!!

[slowupslowdown-under]

will try again!

so, don't split the cable 4 between the two contacts on the hub - just wire it t o 1 of them?

[Ian]

The fifth cable is the one that goes from the light to the hub direct, and is not part of the kemo box.
Don't split cable 4 between the two contacts.

[slowupslowdown-under]

done it!!!

thanks to all, and Ms A.Wench for trying the other day too!

Cables are a bit short so for my next trick I will by some cable tomorrow and bodge it better!

[Ian]

hooray!