SP DYNAMO HUB PD-8X

[Taylor]

Anybody know of a good price?

[johnnystorm]

I think Composite got a good price getting one from the far east, Spa Cycles were doing the hub & revo light combo for £219 but that offer seems to have expired (just had a look). I got mine from keep pedalling, can't give you a hub only price as I had mine built into a wheel & bought a revo as well. They had both the Exposure and plain SP-8 versions.

[JohnClimber]

Johnny - Any chance you can let me know a few things please?

Are these the Revo lights you use http://revolights.com/

Could it run an Chinese type LED light?

During the day can it charge a smart phone plus a GPS at the same time?

Do you notice any drag as some forums say they do?

Cheers

[johnnystorm]

Revo light as in exposure Revo, 800 lumens and output socket for rear light or charging. Has ability to run a front & rear light when you're stopped.

I'm afraid I've no idea if it'll run a Chinese lantern. I'm not planning to charge any device directly but instead to charge a battery or battery charger. Rob Dean has put a lot of work into this and there are a number of solutions to achieve what you want. Things like the Plug 2, etc. I'm sure there is a big thread on here covering it.

[johnnystorm]

Oh, and regarding drag.... When he wheel is in your hand it feels terrible, when spun slowly (in a stand) you can just notice it. When actually riding I don't notice it at all.

[composite]

Johnny - Any chance you can let me know a few things please?

Are these the Revo lights you use http://revolights.com/

Could it run an Chinese type LED light?

During the day can it charge a smart phone plus a GPS at the same time?

Do you notice any drag as some forums say they do?

Cheers

The price I paid wasn't amazing it was just that I had one before they were available in the UK. I would try Koo Bikes though if I was looking for one now, they have given me great prices on other stuff.

It can run other lights but it will be dependant on the connection. Do you have a link to any specific light?

Charging more than one device at a time is a no go really. Also the exact device will effect whether the interface you use between hub and device will need an internal battery or not. I'll post a link in about an hour to some good articles about this stuff, I got to run to a meeting right now.

[HopeValleyPaul]

Good discussion on drag here

http://edwardpickup.com/2013/09/23/gear ... o-systems/

[johnnystorm]

Good discussion on drag here

http://edwardpickup.com/2013/09/23/gear ... o-systems/

In summary, bugger all. :D

[Ian]

On the basis that you don't get owt for nowt, if you're powering a 5W light, you've got to put at least 5W in somewhere else. Allowing for conversion loss, the calculated values of 6-8W seem perfectly reasonable to me.

I might have to start looking at this sort of system for the highland trail

[ericrobo]

I'm keeping an eye on lights and dynamo hubs...
The link to the Revo site says:
"Revolights are currently incompatible with off-road bikes. "

what's the explanation please ? Is it wrong or are you guys talking about road ?

[Ian]

I think revolights.com is not the same as Exposure's Revo. The latter is bundled with MTB hubs, and the former aimed at the commuter market. No association between the two as far as I can tell, so perhaps Exposure didn't trademark "Revo"?

[johnnystorm]

I'm keeping an eye on lights and dynamo hubs...
The link to the Revo site says:
"Revolights are currently incompatible with off-road bikes. "

what's the explanation please ? Is it wrong or are you guys talking about road ?

No connection (ahem) as Ian says above. I'm talking about this:

[Taylor]

Just spoken to exposure and they reckon the PD-8X should be available in the next couple of weeks.

[Blackhound]

On a related note I have been considering a Revo / dynamo set-up for a while. What has put me off a bit is being unable to swap the wheel between bikes.

Someone has told me that there is a Mavic (?) rim which might take a narrow ~35mm tyre but also a 2.1" 29er tyre. Unable to recall who said it, and he did not mention the rim.

If I could use it on a tourer/cross bike and also on my 29er I could almost justify one. Any ideas on a rim that might do the job?

[DoctorRad]

Take a look at the Mavic A319 or A719, both 700c touring rims.

[ianfitz]

Speak to Si at 18 bikes for prices on the hub.

I have one, it works well exept the adapter is 0.1mm wider than the hub axle so its not clamped by the qr. Matt has shaved a bit off for me do it should work nicely now.

Mind is built on an arch ex 29er with multi day fun in mind. Have a revo and will be looking at USB interfaces over the next fee weeks...

[slarge]

I've been pondering this one for a while. I have a Garmin 800 (no replaceable batteries) and a Exposure MaxxD and have been thinking about a dyno hub and revo light. I have ended up thinking that the low expense route is to keep the MaxxD and Garmin, and use external battery packs (I have a Portapow 3400mAh pack today). I think that 2 or 3 more 6600mAh packs will last 6 days or so, and the MaxxD won't need a recharge if I keep it on low. So, adding a bit of risk, I am going to limit the spend to £50 worth of external batteries....

Or maybe panic at the last minute and go the revo light and dyno hub route!

This is my main worry for the HTR (aside from the riding bit)

[composite]

I'm in the same boat with the Garmin 800, unfortunately you can't really charge "direct" through just a usb interface as when the output of the hub goes too low the Garmin tells you that the external power source has stopped. Great feature when running off an external battery but not for what we want. Charging usb battery packs from it though obviously works. Alternatively you can go for one of the ubs interfaces that also has a built in battery and that can provide power at the same time as charging. This way the battery acts like the stand light on the Revo so the Garmin is always powered.

This is a great article on ubs devices, it covers most of what is on the market.
http://cyclingabout.com/index.php/2012/ ... b-devices/

[JohnClimber]

Would putting the power from the hub through this
http://www.sjscycles.co.uk/tout-terrain ... prod32128/
charge a Garmin and/or a smart phone?

Would you experts take a look at this http://www.maplin.co.uk/p/lithium-ion-6 ... bank-n48lk and please tell me in the hub via this above unit would charge this battery up, it says it's input is 5V/1h?

It defiantly is the neatest option if it works.

[ianfitz]

As I understand it the Plug will charge an iPhone. That's what I use for mapping so am likely to go down that route.

Biologic make a battery which will charge off the hub then power various USB devices. Although they claim not to charge later iPhones.

I'm certainly no expert but I think certain batteries would have their lives shortened significantly by charging off a variable input. If guess some sort of regulation is needed?

[johnnystorm]

The lightcharge (in one of the links above) looks interesting:

http://www.twinheads.it/images/doc/manu ... ovable.pdf

http://item.mobileweb.ebay.co.uk/viewit ... cmd=VIDESC

[composite]

More info on this old thread from when I first looking into it.
http://bearbonesbikepacking.co.uk/phpBB ... wer#p21482

[chris n]

Unless you're planning weeks at a time without access to mains power the extra drag, cost and faff of dynamo powered usb charging systems just doesn't seem worth it to me*. Get an external back up battery and use that to charge your device when stopped. Or, heaven forbid, take fewer gadgets.

*and I use dynamo lights on my commuter, but for reliability rather than power options.

[Blackhound]

Thanks Doctor rad, will investigate for nexy spring.

Similar to slarge I have a Garmin Dakota and a USE MaxxD and might look at the external batteries. The additional ones need storing somewhere though.

[DoctorRad]

Re the lightcharge: 250mA isn't a lot of charging current. That would be 8-9 hours for a full charge of my Galaxy S3 at 100% charging efficiency. Some more modern gadgets won't charge from such a low current.

When I get my workspace sorted out, I'm hoping to look at DIY solutions. For those who know one end of a soldering iron from another, this may be a good starting point:

http://pages.citebite.com/d2f2p1r7t4dcn

...with this regulator:

http://uk.farnell.com/tracopower/tsr-1- ... dp/1696320

Make D1 a 30V zener with a nice beefy power rating, or else a transient voltage suppression diode.

I have not tested this and it might Blow Sh!t Up, so proceed with caution. At the very least, check with a voltmeter that the output voltage doesn't go (much)above 5.2V at the fastest speed you're ever likely to reach.

Dynamos are funny things when it comes to extracting maximum power at all speeds from them, nothing like as simple as you might think.