Waterproofing Electrical Connections

Hear is a useful idea I found on the YACF forum

Somnolent said:

charging of Garmins from a dynamo while on the move is problematic even in the dry.
Nothing that can’t be overcome mitigated with a little ingenuity.
Been running my Etrex (HCx) from the Luxos USB offtake for a couple of years now.
I’ve fettled a 6″ cable with sugru at either end to make something tolerably water-resistant, and which minimizes mechanical loads/vibration on the USB socket.
Keep meaning to remove the cable when it rains, close up the covers and run on battery for the duration of the precipitation, but somehow I always seem to forget and its still going strong.

From the Sugru website:

Sugru sticks to wood, metal, glass, as well as most plastics and fabrics.
It bonds much stronger than contact adhesives, adhesive strips or silicone sealants.
Once it’s cured, Sugru is waterproof, just like other rubbers.
You can use it in the shower, the sink or even the sea.
And thanks to Sugru’s heat-resistance, it’s even dishwasher-proof.
Sugru isn’t rigid like other glues – cured Sugru bends like a firm, flexible rubber, so it’s perfect for use on textiles, shoes or even low-current cables.

Consumer Reports says:

What we found. As we expected, a pack doesn’t go very far. Sugru sticks adequately to non-porous surfaces but not as well as a true adhesive. It isn’t as soft as some other silicones once cured, and it’s not especially strong. And while you can compress it without problems, it didn’t handle stretching well.

Bottom line. We wouldn’t use Sugru where failure of the bond could create a safety or health issue. But in cases where filling a gap is essential, a structure requires some reinforcement, or surfaces don’t align well, we found it fun and useful—there are many situations where the usual adhesives wouldn’t apply. Still, we recommend it for non-critical repair tasks.

Sinewave Cycles

Sinewave Cycles Revolution

Sinewave Cycles Revolution Bicycle Dynamo USB Charger featureThe Sinewave Cycles Revolution is a bicycle dynamo powered USB charger.

It converts electricity generated by hub and bottle dynamos to USB output.

The Revolution allows users to charge USB-powered devices while riding.


  •       Best in class efficiency
  •       High Speed Overload Protection
  •       Simple Installation
  •       Light weight
  •       Shock and vibration toughened
  •       Waterproof
  •       Gold-plated USB connector won’t rust or corrode


  •       Starts charging at 3.5 MPH (5.5 km/h)
  •       Full charging at 9 MPH (14.4km/h)
  •       Max current: 1 Amp
  •       Weight: 37 grams
  •       Dimensions: 14x35x54 mm
  •       Wire length: 36″ (91 cm) (contact us if your setup requires a longer wire)
  •        Wire ends: Stripped wire

Sinewave Cycles Reactor

Screen Shot 2014-03-19 at 8.56.32 pmWe’ve taken the performance of our Revolution dynamo-powered USB charger and shrunk it into a package that fits above the star nut in a threadless steerer tube, with a pass through for the 6mm bolt.  The only visible part is a custom CNC-milled stem cap holding the USB connector.  The cap is only 10.6mm tall and available in silver, black, red and blue.  The Reactor is compatible with 1″ and 1 1/8″ threadless systems.