Can you run a Hub dynamo light from a battery?

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BigFoz
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Joined: 2 Jun 2011, 12:33pm

Can you run a Hub dynamo light from a battery?

Post by BigFoz »

I'm considering converting from battery to hub dynamo. As I do so, I'm going to need a complete new front wheel, so I'd like to try the light with a battery first before committing a lot of money and being stuck with something no better than I already have for 4x the money...

Am looking at a Schmidt Edelux II High Power LED Headlight, it's a 6v/3w system, can I run it from the 6V battery I already have from my Ay-Up light set? While I understand bikes intimately, I'm not quite so familiar with elecktrickery... Is there a DC/AC issue?
I asume a battery input would appear like a long ride at maximum output from hub to the light?
I assume I'd also need to make some sort of conversion cable to convert the Edelux boxy connectors to the Ay-Up round one... (Which may require more electrickery than I can manage...)
nickpaton
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Re: Can you run a Hub dynamo light from a battery?

Post by nickpaton »

From this video it seems you can https://m.flickr.com/#/photos/44932385@N06/6899239298/

EDIT from the edelux brochure "battery powered use is not recommended and any voltage of more than 7.5V will damage the unit. Voltage of less than 6.5V results in reduced brightness.
So I guess you'd OK with battery voltages between 6.5V and 7.5V
http://www.nabendynamo.de/service/service_en.html, scroll installation instructions edelux.
Last edited by nickpaton on 21 Apr 2014, 6:31pm, edited 2 times in total.
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[XAP]Bob
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Re: Can you run a Hub dynamo light from a battery?

Post by [XAP]Bob »

Depends on the light, and what gubbins it uses.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
MikeF
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Re: Can you run a Hub dynamo light from a battery?

Post by MikeF »

Or to jump directly to the page see http://www.nabendynamo.de/produkte/pdf/english/Montage_Edelux_e.pdf where it says "Battery-powered use of the Edelux is not recommended. Voltage higher than 7.5 V – even for a very short time – may damage electronics and LED. Though voltage lower than 6.5 V is uncritical, it reduces brightness."

Dynohubs generate AC. Even if it works from a battery, you may not be giving it a fair test.
Depends where you want to ride, but in my experience to date B&M and Philips lights give good illumination on the road, without adopting the blind everything in sight approach. I'm sure Edelux is at least as good or better as it uses similar technology. The beams are shaped not to dazzle are but still highly visible to other road users.

Can you rebuild your front wheel? One of the cheapest places for hubs and spokes is Rose Bikes. http://www.rosebikes.co.uk/article/shimano-hub-dynamo-dh-3n30a/aid:592136 You would need to alter the connectors for the Edelux to run from a Shimano hub.
"It takes a genius to spot the obvious" - my old physics master.
I don't peddle bikes.
pete75
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Joined: 24 Jul 2007, 2:37pm

Re: Can you run a Hub dynamo light from a battery?

Post by pete75 »

MikeF wrote:Depends where you want to ride, but in my experience to date B&M and Philips lights give good illumination on the road, without adopting the blind everything in sight approach. I'm sure Edelux is at least as good or better as it uses similar technology.


Not just similar technology to B&M but the same. From the Roseversand website "Effective technology from Busch and Müller is used in the Edelux, and the offset IQ-Tec mirror ensures a wide, evenly illuminated cycling path."

If you want to see how effective any dynamo light is without splashing out on a hub dynamo wheel why not just get a cheap bottle dynamo. It will produce 6 volts and 3 watts. I've got a few hanging about and I'd sent you one for the cost of the stamps.
'Give me my bike, a bit of sunshine - and a stop-off for a lunchtime pint - and I'm a happy man.' - Reg Baker
BTP
Posts: 60
Joined: 1 Sep 2009, 1:30am
Location: Perth, Western Australia

Re: Can you run a Hub dynamo light from a battery?

Post by BTP »

BigFoz wrote:I'm considering converting from battery to hub dynamo. As I do so, I'm going to need a complete new front wheel, so I'd like to try the light with a battery first before committing a lot of money and being stuck with something no better than I already have for 4x the money...

Am looking at a Schmidt Edelux II High Power LED Headlight, it's a 6v/3w system, can I run it from the 6V battery I already have from my Ay-Up light set? While I understand bikes intimately, I'm not quite so familiar with elecktrickery... Is there a DC/AC issue?
I asume a battery input would appear like a long ride at maximum output from hub to the light?
I assume I'd also need to make some sort of conversion cable to convert the Edelux boxy connectors to the Ay-Up round one... (Which may require more electrickery than I can manage...)


You can run it from a battery, but, as said by others, you have to regulate your battery output to about 7V. Much more and you will over-voltage the LEDs. Also, to keep battery life to the maximum you will need to use a switch-mode, rather than a linear regulator. If this sounds too complicated and your not an electrickery person, then there are plenty of LED lights out there designed for battery use.

Or, go down the dynamo route as suggested. I have a Scmidt hub dynamo fitted to both my bikes. If I suddenly have to make an evening dash I don't have to worry whether any batteries are charged. Pete75's offer of a test Dynamo in exchange for a few postage stamps seems a good one!

Cheers,

Tony
BigFoz
Posts: 491
Joined: 2 Jun 2011, 12:33pm

Re: Can you run a Hub dynamo light from a battery?

Post by BigFoz »

Can you rebuild your front wheel?


Not into a dyno hub as I'm using Campag Vento / Khamsin across the fleet, with odd numbers of spokes. Not sure anyone does a 27spoke Dynohub!

I've got an old bottle dynamo in the spares box. Not keen on bolting it to the carbon forks (leery about tightening anything onto them other than in provided fittings...)

I'll have to bite the bullet and do the whole thing. Don't want to buy cheap as experiment as I'll likely then want to upgrade. My commute contains about 12miles each way (of 22) of unlit B-Roads. It's just long enough to have doubts about battery life, with risk of running dry in the darkest part, so I'm tending to ride in, train most of the way home. While battery SHOULD last fine, if it didn't I'd be gubbed as they say up here. Last bit is also fastest piece of run home, so don't want to be running on my emergency light either...
tatanab
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Joined: 8 Feb 2007, 12:37pm

Re: Can you run a Hub dynamo light from a battery?

Post by tatanab »

I do not understand the logic. You are wary about running out of battery if you use a battery light, but you ask if it is possible to run a dyno light from a battery? Surely that gives the same problem of running out of light.

Perhaps what you want is a front light with the cut off beam which is common on B&M etc dyno lights. This is available in battery lights too. The old B&M Ixon IQ does this and has a battery life of 20 hours on low and 5 hours on high power from 4 AA batteries. I found low was good enough for 20mph in dark lanes. That light is an old design and I see there is a new version that does 80Lux http://www.rosebikes.co.uk/article/b--m ... aid:703598 Then I switched to Philips Saferide 80 http://www.rosebikes.co.uk/article/phil ... aid:642260 which has the same beam cut off, also runs on 4 AA batteries but has a run time of 5 hours on low and 2 on high (from memory) and I almost never used high. I believe Philips is dropping its bike lights so I suggest you look at the newer range of B&M Ixon IQ light. I suppose if you use a battery light my advice would be to use one with AA batteries not some internal battery that you cannot get at to change them if needed.
pete75
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Re: Can you run a Hub dynamo light from a battery?

Post by pete75 »

BigFoz wrote:
Can you rebuild your front wheel?


Not into a dyno hub as I'm using Campag Vento / Khamsin across the fleet, with odd numbers of spokes. Not sure anyone does a 27spoke Dynohub!

I've got an old bottle dynamo in the spares box. Not keen on bolting it to the carbon forks (leery about tightening anything onto them other than in provided fittings...)

I'll have to bite the bullet and do the whole thing. Don't want to buy cheap as experiment as I'll likely then want to upgrade. My commute contains about 12miles each way (of 22) of unlit B-Roads. It's just long enough to have doubts about battery life, with risk of running dry in the darkest part, so I'm tending to ride in, train most of the way home. While battery SHOULD last fine, if it didn't I'd be gubbed as they say up here. Last bit is also fastest piece of run home, so don't want to be running on my emergency light either...


1. You can fasten the dynamo to a seat stay as well as front forks.

2. Have you ever considered carrying spare batteries or changing to another brand of battery light with longer running times? I think they're made with several hours running item even the sort that use 4 AAs like I have on one bike. It provides more than enough light even on totally unlit country lanes.
'Give me my bike, a bit of sunshine - and a stop-off for a lunchtime pint - and I'm a happy man.' - Reg Baker
Colin Stanley
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Joined: 12 May 2007, 7:05pm
Location: Somewhere in Kent

Re: Can you run a Hub dynamo light from a battery?

Post by Colin Stanley »

I run a B&M Cyo from a Maplins 6v lead acid gel 10Ahr battery. Just get the polarity right.
tim-b
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Joined: 10 Oct 2009, 8:20am

Re: Can you run a Hub dynamo light from a battery?

Post by tim-b »

Hi

I commute all year round, and I can't wait until April to pack my front light away for a few months and "clean up" the look of the bike
I keep a set of small battery LEDs attached 24-7 so I don't get caught out in summer and as my winter back up

I don't know about your budget, but my Li-Ion battery pack lights have a good beam in darkness at below max. power and a better life, and you can get larger packs either as an option or custom-made (http://www.mtbbatteries.co.uk/ provided me with good service)
Keep them charged to a minimum 50%, plus a few minutes every month, and they'll be ready if you go for a later/longer summer ride

Regards
tim-b
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[XAP]Bob
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Re: Can you run a Hub dynamo light from a battery?

Post by [XAP]Bob »

tatanab wrote:I do not understand the logic. You are wary about running out of battery if you use a battery light, but you ask if it is possible to run a dyno light from a battery? Surely that gives the same problem of running out of light.

He wants to be sure that the light is good enough before buying a new wheel.

I'd look at the "rim dynamo" linked from one of these pages not too long ago.

Look nice and lightweight, and should be decent in their efficiency.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
BigFoz
Posts: 491
Joined: 2 Jun 2011, 12:33pm

Re: Can you run a Hub dynamo light from a battery?

Post by BigFoz »

I do not understand the logic. You are wary about running out of battery if you use a battery light, but you ask if it is possible to run a dyno light from a battery? Surely that gives the same problem of running out of light.


Err, it's now summer (ish), which give me opportunity to trial the light on occasional dark rides without the pressure of needing to run both directions to work completely in the dark, and without the need to spend all of the money in one go.
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