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• #5352
Swapping a BB is much more appealing than buying a new wheel as well :)
For a very basic version one could probably rig something up with a triple crankset using a bit of chain on the granny ring to drive the "dynamo". Not on a Brompton obviously, just some old £10 bike or whatever. Need a nice narrow (part of) hub so as not to interfere with your legs.
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• #5353
As far as I know, the dynamo works by (very basic) having a magnetic plate spinning inside a copper enclosing. This moves the electrons inside the copper which equals to energy.
My idea was to use a magnetic plate on or inside the BB spindle INSIDE the BB shell and a wire enclosing INSIDE the BB shell (along its inner walls) as a dynamo.
The transferring cable would then go up along the downtube. Or come out from the BB cups.
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• #5354
Actually the opposite: Dynamos produce electric current by rotating a wire within a magnetic field.
So swap the idea above...but I guess you got what I mean :) -
• #5355
Imagine that spindle in the pic to be the BB spindle, the magnets would be attached to the BB internal walls.
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• #5356
Either way works. Moving magnet or moving wire. Wires are easier to move though...
I'd like to see one built! Do you have the machining equipment/etc. to make something like that?
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• #5357
Not at all, but experimenting with this shouldn't be that complicated.
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• #5358
I can’t see it working. To fit it inside a standard BB you’d need tiny magnets and too few segments in the commutator which wouldn’t induce much current for one thing, but the real problem would be the speed which the unit would turn. 60 or so rpm would produce bugger-all output. It’s why the old-school SA Dynohub was so weak on anything other than 20” wheels - 27” wheels just didn’t generate enough power. Smaller wheels spin faster which is why dynamos work well on Brommies etc.
Personally I don’t think they’re worth the hassle. USB rechargeable lights are so powerful and simple these days, I’d rather just stick with those.
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• #5359
Isn't he referring to one of these?
EDIT: new paged. Apparently he isn't.
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• #5360
You're right!!! Never thought about the rotational speed :)
Good point. -
• #5361
EDIT: new paged. Apparently he isn't.
ahhaha no I wasn't :)
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• #5362
Customer wants, customer gets.
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• #5363
amazing, needs more colour obvs
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• #5364
other than buying the jtek titanium seatpost this week (which is amazing) I have also bought titanium rear triangle which @maynardeames is insisting I install so I will
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• #5365
Let’s also mention a bike shop quoted £110+vat to fit a rear triangle?! Wtf.
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• #5366
Mine is blue and orange. When the cables need replacing I'd like to use not-black - can you get Brompton length ones in interesting colours?
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• #5367
You can get whatever you want... just reuse the Brompton ends if you can and use linear cabling. Shimano stuff does not work well at all etc.
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• #5368
Cable lengths, and other stuff found on here...
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• #5369
Yes, Black.
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• #5370
I have a genuine Brompton rear triangle with a snapped-off thingy-wotsit where her ez-wheel should for. It’s stupidly light. It’s currently being used as a toilet roll holder in the shop loo. What a waste.
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• #5371
I know a guy that could fix that...
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• #5372
Titanium? I now have the kit to weld titanium. Reckon it'd be repairable? It's not structural, after all. And I have quite a lot of scrap titanium tubing.
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• #5373
I have no watts
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• #5374
Much interest aroused.....
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• #5375
I hasten to add I haven't actually tried welding titanium yet.
Yeah but the dynamo in the end is some wire cabling around a spinning magnet. Magnet attached to normal spindle and wire as a casing (as you see plastic casing for vintage BBs)
In the end normal wheel dynamos are smallish. Could be done and also with a tiny bit of battery to hide inside the tubes that depart from the BB shell...need to patent this :)