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almost finished a lot of stuff

A project log for Ultra-Portable Sustainable Electric Generator

Combines 3 projects I just started: foldable 50W solar panel, campfire-based thermoelectric generator, & RasPi2 lapdock. Fits in a backpack.

dylan-bleierDylan Bleier 05/23/2015 at 21:440 Comments

I put together the solar panel (minus the coatings and flexible backing. Around mid-day it gave 20V at first and then 19V after heating up in the sun, and it charged the lead acid battery pretty quickly. I redundantly wired all 10 cells in series, using short lengths of stranded wire. some of the wires are too weak, so I'll replace them with more 120VAC cord. The panel folds up lengthwise first, then the two strings of 5 cells fold over each other into one tight bundle. I will need to get a hard case to protect the finished product. As for the charging circuitry, I installed it all in the case with the fans, using a drill and some hot glue.

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enclosure / charging circuit to do list:

- drill/cut/attach clear plastic front face; mount switches and USB x2 using hot glue, holes for screwdriver to access pots, output cord/jack for lapdock

- get and attach: replacement LED voltmeter for the one I blew up by replacing the voltage converter with a pot that I overheated, also a female 1/4" audio jack for 12V out.

- add fine mesh screen to protect fan and everything inside from debris (?), add more holes on top, front and sides to improve air flow (?)

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solar cell to do list:

- replace the weak wires on the solar cells with more stranded 120VAC cord

- add a diode in series with solar panel or step up/down charging circuit to prevent any possible damage

- TPO or TPU encapsulant (I think these perform much better than EVA if I can find them in the right formulation somewhere?) for the solar cells, apply this and then the FEP using heat gun under mild vacuum (e.g. shop vac) after cleaning cells with suitable solvent, and cleaning off rosin flux from soldering

- get a tarp or something and cut it to size, melt/seal/sew/tape edges so it won't fall apart; mount the solar panel on this and secure the bendy wires; if necessary add something to make the cells more rigid

- get/make rigid storage enclosure for solar panel, and foam strip spacers so packing the cells in the box won't damage them while in transit. possible items for an enclosure include a contractor's clipboard box, or a DIY box I could make from scrap bamboo flooring.

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thermoelectric generator to do list:

- get peltier junctions and clamp a water cooled aluminum block to one side and clamp a series of heavy copper wires to the other side. find a second barrel jack connector for this

- make a series of experimental high temperature peltier junctions using inexpensive materials (e.g. graphite and aluminum)

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RPI lapdock to do list:

- research config.txt settings, reconfigure to work with lapdock... this may take some time, and it's possible I soldered the wrong USB data wires since there were 5 or 6 wires in that jumper that came inside the lapdock

- research startup sequence, add switches where necessary in the USB and/or HDMI wiring.

- once it all works perfectly, slim down all the parts, finish the desoldering of the ethernet and USB ports and move them, hot glue everything into place inside the RPI including USB drive, GPIO cable, and then close it all up.

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