Dyno hub testing

[rufus748]

I've never been that impressed with the ability of by hub to light my Revo lights four bulbs, it's used mainly for charging my gps.
Yesterday I rode down a steep hill with it on and the four only came on well over 20mph.
It's set up on a 29+
I've bought a volt tester which I've wired to the hub. Instructions are poor, so anyone one know which setting I should use??
Thanks

[Bearbonesnorm]

AC volts straight from the hub ... should output around 6v.

[GregMay]

What Stu said. No issues with mine 2 years in.

[AlasdairMc]

I've never been that impressed with the ability of by hub to light my Revo lights four bulbs, it's used mainly for charging my gps.
Yesterday I rode down a steep hill with it on and the four only came on well over 20mph.
It's set up on a 29+
I've bought a volt tester which I've wired to the hub. Instructions are poor, so anyone one know which setting I should use??
Thanks

The four should come on at 15mph AFAIK, and they do on mine. I reckon it'd be difficult to test it unless you wire the voltmeter across the contacts and go riding on Tarmac.

[Chew]

Isn't it based on rpm, so bigger wheels with need a higher speed?

[atk]

Which hub are you using? Exposure/SP?

[Justchris]

I've never been that impressed with the ability of by hub to light my Revo lights four bulbs, it's used mainly for charging my gps.
Yesterday I rode down a steep hill with it on and the four only came on well over 20mph.
It's set up on a 29+
I've bought a volt tester which I've wired to the hub. Instructions are poor, so anyone one know which setting I should use??
Thanks

The four should come on at 15mph AFAIK, and they do on mine. I reckon it'd be difficult to test it unless you wire the voltmeter across the contacts and go riding on Tarmac.

You could try rollers. A roadie friend may have some.

[trail717]

Isn't it based on rpm, so bigger wheels with need a higher speed?

Yes--and both Son and SP offer dyno hubs specifically made for smaller diameter wheels--so if one of these type hubs were unknowingly laced up to a 700/29 rim they would not produce max power at normal speed.

OP should be able to easily verify if his hub is, or is not, meant to be used with a 29 rim size--I belive both manufactures have this info on their web sites

[burty]

i have the sp exposure hub on a krampus 29+.
all four lights are on at around 10-12 mph

[rufus748]

Burty, I remembered when I rode with you on the WRT your lights were on all the time hence my doubts over my set up. It's taken me until now to sort it...!
Hopefully I'll have some readings soon.

If the hubs ok, anyway I can test the light separately?

[atk]

Are you trying to charge something and run the lights at the same time?

[rufus748]

Atk, "Are you trying to charge something and run the lights at the same time?"

No, I've got a Cyclecharge wired to the hub along with the Revo wire but only use one at a time. I'm conscious that the hub won't produce enough juice to fully power the light and charge a separate device even if it was working properly.

[ianfitz]

Atk, "Are you trying to charge something and run the lights at the same time?"

No, I've got a Cyclecharge wired to the hub along with the Revo wire but only use one at a time. I'm conscious that the hub won't produce enough juice to fully power the light and charge a separate device even if it was working properly.

My cycle 2 charge had a fault where it would draw power with nothing plugged in. It also didn't output much charge either!

[rufus748]

Test results:
Direct from the hub:
10kph - 7.8
15kph -12

cycle 2 charge: 6kph - 5.16 and didn't rise irrespective of a rise in speed

Tried the light again with just the Revo lead attached to the hub and four lights only started to come on at 26kph (16mph) and were fully bright at 32kph (20mph).

The readings direct from the hub don't make much sense to me looking at the output chart on the SP website, appear to be far to high (or I've set the multimeter wrong...)

Given Burtys's light I'm thinking I've got an issue with the light rather than the hub?

[JerseyMountainBiker]

My revo laced to 29 rims and 2.4 Maxxis Icon only lights up all 4 LEDs at 15mph. Not sure if this is right or wring but I've had two hubs now (first one stopped working and was replaced straight away by Exposure) and both have been the same i.e. 4 LEDs at 15mph+.

[johnnystorm]

Atk, "Are you trying to charge something and run the lights at the same time?"

No, I've got a Cyclecharge wired to the hub along with the Revo wire but only use one at a time. I'm conscious that the hub won't produce enough juice to fully power the light and charge a separate device even if it was working properly.

My sp8 can charge my smart phone while running Google satnav and produce usable light from my Fargo when not really hoofing along.

[ctznsmith]

All four lights on mine somewhere between 12 and 14mph with a 700c wheel and a 40c tyre.

Can test with a 29x3.0 at the weekend.

[rufus748]

Thanks to everyone so far.
I've emailed Exposure and I'm waiting a response.