carrying charge from hub dynamo
- simonineaston
- Posts: 8003
- Joined: 9 May 2007, 1:06pm
- Location: ...at a cricket ground
carrying charge from hub dynamo
As my new build begins to take shape, another decade-long bugbear (not exactly sure what one of them is...) may be addressed, to wit how to pass the charge from the dynamo in the front hub to the bits that need it. I see a tempting hole at the base of both fork legs. At the same time, my mind turns to the way that car electrical systems used the chassis as the ground - do they still do that? As most cars are now effectively computer-controlled, they must need high-quality electrical stability... any comments, you sparky-type people?
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
Re: carrying charge from hub dynamo
Yes, cars still use the body as earth/ return. There is some non-conductive gluing where there would have been welding, and a lot more digital stuff and a fair bit of multiplexing, but there's also lots of simple traditional analogue circuitry.
Jonathan
PS: Most (if not all) electric-only vehicles have a traditional low-voltage battery and circuitry in addition to the main drive system.
Jonathan
PS: Most (if not all) electric-only vehicles have a traditional low-voltage battery and circuitry in addition to the main drive system.
Last edited by Jdsk on 5 Aug 2020, 5:49pm, edited 1 time in total.
- simonineaston
- Posts: 8003
- Joined: 9 May 2007, 1:06pm
- Location: ...at a cricket ground
Re: carrying charge from hub dynamo
I guess I'm thinking out loud really, but I was wondering if there is any advantage to using the cycle frame as ground and I guess the answer is a loud NO for the simple reason that whatever you connect will have to be supplied by at least one wire, so it makes no sense to use the frame as ground 'cos you might just as well use a pair of wires as one.
Never-the-less I would like to get rid of the traditonal wire "wrap" of the fork leg, just for once, by passing the wire up inside...
Never-the-less I would like to get rid of the traditonal wire "wrap" of the fork leg, just for once, by passing the wire up inside...
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
Re: carrying charge from hub dynamo
On here about it before and was given advice.
Providing you have a breather-hole top and bottom of the fork leg .....................
Pass a double loop of thin fishing wire down from from the top hole to the bottom hole by the dropout.
It won't come out, but with a piece of wire or a pick, pull the loop out.
Thread a bit of thin string through the loop and pull the fishing line out and the string will come through the top.
This means you then have a string right through the fork leg.
Connect a nice long length of your preferred electrical twin-core to the string, and pull it through.
This works a treat, I promise ................. but you need breather holes top and bottom of the fork leg.
Providing you have a breather-hole top and bottom of the fork leg .....................
Pass a double loop of thin fishing wire down from from the top hole to the bottom hole by the dropout.
It won't come out, but with a piece of wire or a pick, pull the loop out.
Thread a bit of thin string through the loop and pull the fishing line out and the string will come through the top.
This means you then have a string right through the fork leg.
Connect a nice long length of your preferred electrical twin-core to the string, and pull it through.
This works a treat, I promise ................. but you need breather holes top and bottom of the fork leg.
Mick F. Cornwall
Re: carrying charge from hub dynamo
I use my frame as part of the circuit on my dynamo equipped bikes so i can manage with a single wire to the lights. My lighting is often diy and i have never had any problems with the arrangement. You will have to earth the lights so have to ensure correct polarity if you have led lighting which is polarity sensitive.
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840
- simonineaston
- Posts: 8003
- Joined: 9 May 2007, 1:06pm
- Location: ...at a cricket ground
Re: carrying charge from hub dynamo
So what would you say are the advantages of the single wire? I can see that a single wire is potentially thinner, and therefore fit in smaller holes, but I can also see that a thin wire is more at risk of damage...a single wire to the lights
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
Re: carrying charge from hub dynamo
No advantage of a single wire.
If you use one, the earth return has to be fitted onto bare metal at either end.
No bare metal on my bikes thank you very much!
If you use one, the earth return has to be fitted onto bare metal at either end.
No bare metal on my bikes thank you very much!
Mick F. Cornwall
- simonineaston
- Posts: 8003
- Joined: 9 May 2007, 1:06pm
- Location: ...at a cricket ground
Re: carrying charge from hub dynamo
That's rather what I thought - there's not supposed to be any bare metal on mine, either - except for the patches where Pashley's cheapo powder coating has flaked off! Thank goodness for my ancient tin of Hammerite!Mick F wrote:No advantage of a single wire. If you use one, the earth return has to be fitted onto bare metal at either end.
No bare metal on my bikes thank you very much!
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
Re: carrying charge from hub dynamo
Threaded bosses?
Jonathan
Jonathan
- simonineaston
- Posts: 8003
- Joined: 9 May 2007, 1:06pm
- Location: ...at a cricket ground
Re: carrying charge from hub dynamo
Yeah but - aren't they full of bolt?Threaded bosses?
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
Re: carrying charge from hub dynamo
Theres lots of places on a bike which are not painted. Alloy racks, bolts which attach brakes are useful sources for a front light fitting. And has been stated most threaded bosses will earth via the attachment bolt.
If you check for continuity using a multimeter it may surprise you.
If you check for continuity using a multimeter it may surprise you.
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840
Re: carrying charge from hub dynamo
The disadvantage of using the frame for the return current is that if you are running a front wheel dynamo or a fork mounted light with a rear dynamo then the return path is through that nice greasy, dirty headset. Possibility of problems. For example of how bad this can be in automobiles - just look at the number of old cars where the rear lights go off when the brake lights come on or the indicators are set. This is due to dirty connections to the car for the return. Of course, using the frame for the return has served generations of cyclists perfectly adequately, but I would not consider it ideal.
Re: carrying charge from hub dynamo
simonineaston wrote:Threaded bosses?
Yeah but - aren't they full of bolt?
I don't use the frame as a conductor, but if I did... ring terminals?
Jonathan
Re: carrying charge from hub dynamo
backnotes wrote:https://www.peterwhitecycles.com/schmidt-sl.php
Way too easy, not the CTC way.
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Deutsche Luftschiffahrts-AG
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Deutsche Luftschiffahrts-AG
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