sp-pd8 dynamo hub question?

[ton]

anyone know if you can fit some kind of switch to one, to turn it off?

[jameso]

Not unless it's a switch in the wire from the hub, it's not really needed to switch the mechanism itself off anyway. Ison did have a switchable version a while back though, a bit heavier but bonus of larger flanges. Had a rotational switch at the hub edge to disengage the dyno magnets. Can't remember if it was SP or someone elses.

[sean_iow]

It only generates power when connected to something. You could put a switch in the lead but I just unplug the lead from the light when I don't need it. The resistance you can feel when you turn the wheel would still be there as that's the magnets passing each other but I've never noticed it when riding. There will in theory be more resistance when plugged in but it's negligible.

[ton]

so there is not much chance of the light unit blowing then?

[sean_iow]

Not unless it's a switch in the wire from the hub, it's not really needed to switch the mechanism itself off anyway. Ison did have a switchable version a while back though, a bit heavier but bonus of larger flanges. Had a rotational switch at the hub edge to disengage the dyno magnets. Can't remember if it was SP or someone elses.

I remember seeing the one with the rotatable bezel to turn it off, can't remember who made it. I guess it moved the magnets? It seemed like another area for water to get in to me, which is the last thing a dyno hub needs

[sean_iow]

so there is not much chance of the light unit blowing then?

I've had 45mph on my mtb (downhill on the road in Devon) with the revo connected with no problems. The circuitry protects the light. I would predict that the life of the LEDs will exceed the life of my legs to power it

[ton]

cheers for the info.

[ScotRoutes]

Oh, and you do eventually get used to folk telling you you've left your light on

[johnnystorm]

I'll be mightily impressed the day that an SP manages to outlast a light.

[sean_iow]

I'm on my second hub, PD-8X, but the warrantee replacement was a brand new unit as they were out of recon ones and I had to get new spokes as the casting is new with different (bigger) flanges so I'm hoping the changes are to accommodate bigger/better bearings and/or seals. But I'm a glass half full kind of guy, fingers crossed they've listened to the feedback and improved it.

[pistonbroke]

I have a setup which suits me well. I connect the Dynamo to a Kemo device which allows you to switch from running a Revo directly to charging a buffer battery via a USB lead and then powering a phone or gps. Kemo's are good value at around £30 from maplins on line and imo work better than the Plug devices costing 4x more. http://www.maplin.co.uk/p/kemo-bicycle- ... -usb-n18dd

[SixPotBelly]

No need for an inline switch, unless your headlight doesn't have one and you want to to turn it off. (I've seen gushing reviews of that K-lite stuff and wondering why all the fuss about it having a toggle switch, then realised he uses a light without one). I use a B&M headlight, with a USB charger in parallel. When the light is on it takes enough power to work and the USB power is reduced. When it's off the USB charger gets full power. No toggle switch needed.

I'll be mightily impressed the day that an SP manages to outlast a light.

Maybe not relevant to the OP, but have had no problems at all from my PL8. I've read conjecture that it's the 12mm ones that suffer rather than the QR.

[ton]

2nd question, can I somehow had a junction box to wire a rear light from the hub. or is it solely for the front light?

[SixPotBelly]

My front light has wires coming out for rear light wiring to connect to. They're switched along with headlight.

[sean_iow]

Which light are you using? The Revo has an smart port for the Red Eye Rear which is available with a cable long enough to route along the top tube.

[ton]

excuse my idiocy..........

the rear is a secura the front a bm. the rear is wired, and the connections were not plugged in. they now are.
and you can turn them off via the back of the front light unit.

sorted now...............cheers all.