Having just finished a 7 day bicycle tour from Pittsburgh to Washington DC via the GAP Trail and the C & O Canal with the Fuse 4W to keep his cell phone and iPad going, Ben Schapiro set out to create a custom 10 Watt charger for bicycle touring. Below are the requirements, parts and instructions…thanks Ben for sharing.

Core project requirements:
– Charge both a V11 and V39
– Fit inside the dimensions of the baggage that goes on the rear rack.
– Fold up to fit in a dry bag or pannier when not needed
– Lightweight
– Have a flexible mounting system
– Non-rigid base.
– Provide storage pace for batteries and adapters
– Built from proven components
– No protrusions to chafe or tear panniers/rack bag.
– No kludges

Parts
3 – 3.4watt 6 volt solar panels
1 – 3 panel 6v/18v circuit box
1 – V11 Battery (already owned)
2 – V39 Battery (already owned)
1 – 18in x 4ft roll vinyl/foam/fabric laminate shelf liner
6 – plastic snap grommets
1 – 1 in x 5 ft roll of Scotch outdoor mounting tape
3 – Velcro dots
12 – small nylon washers

Step 1
Panels and grommets are set in a rough layout to verify size of backing. A finished size of 48cm by 31cm with a little extra on the backside to form a flap fit everything within the space on the rear of the bike.
The panels are spaced 4.5cm apart, enough that they can be folded back on each other for stashing in a pannier.

Step 2
Cut backing to size and double over so the front face has a dimension of 48cm x 31cm with 10cm (under the V39) more on the back for a flap. This will be cut to size later.

Step 3
Apply Scotch outdoor mounting tape – double-sided foam tape, which adheres nicely to the foam and vinyl backing material. The red cover tape is removed and the material that will be the front is folded over and pressed on to the tape. The tape keeps everything aligned during assembly and seals the sides of the pouch between the grommets.



Step 4
Install six plastic grommets 3/8 of an inch in from the edges. The foam backing and the foam exterior mounting tape are thicker than what the grommets normally accept, but judicious use of a vise solves that problem. Mount the panels by making a small slit for each screw post and one for each wire. The panel connector/voltage selector stays inside the pouch along with the battery being charged. Use three velcro dots to secure the flap, or snaps work even better. Small washers at each screw post to reinforce the backing material.

Step 5:
Trim flap and add snaps or Velcro. To charge a V11 or use the accessories/adaptors that come with the V11 or V39 batteries you will need a 5.5mm x 2.5mm male to 3.5mm x 1.1mm female adaptor to plug to the Power Out cable on the 3 panel circuit box.

On the bike, the setup weighs 1.7lbs or 0.75kg

Folded:
Fits right inside the 35L dry bag or rear pannier.

Read more about solar charging and bicycle touring on our guide.

3 Responses

  1. Kiki

    Hi Michael,

    Are you charging both the V15 and V39 batteries simultaneously or one at a time?

    Roughly how long does it take to charge each of these batteries in direct sunlight?

    Thanks!

    Reply
  2. Michael

    I’m curious about how this system is performing in the field (as well as what it cost you AND the time it took to build it).

    I love the design in general – folds up to store, flexible so it sits on teh load however you want it to, enough capacity to charge a fair amount of stuff.

    What ARE you actually providing power for? Phone, tablet or iPad, camera, more than that?

    Reply
    • Ben Schapiro

      Michael,

      The three panel set up is used to keep two V39 and one V11 battery charged which in turn keep an iPhone and a iPad charged year round. So it is outside almost every day it isn’t raining or snowing. The design is not waterproof by any means.

      Within the limits of the three panels and the sun the charging works as expected. The materials used have stood up just fine. No rips or failed seams etc.

      Excluding the parts from Voltaic parts cost was under $25.

      Reply

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