Hello Hackers!   For a long time I have been fascinated by the thoughts of free and renewable energy.  My inspiration to build this device came from a cabin in the woods which was surrounded by tall trees which blocked out the sun and the wind.  This left me unable to put up solar panels or a wind generator.  There is however a small creek which runs on the property.

My online research led me to some work in Guatemala by Sam Redfield.  Sam built a very similar device for a small community which was isolated from power.  Sam’s work was featured on MAKE and Gizmodo in 2008.

The power generator in the system is a Permanent Magnet Alternator (PMA) with a pelton wheel directly attached to the shaft.  Water is sent through four jets which strike the wheel causing it to rotate.

The bucket and lid components were initially assembled at the Vancouver Hackspace.  The first version of the bucket lid had the water distribution system assembled from 1 inch PVC parts.  After on-site tests failed, I found that this system was too inefficient to distribute the high-pressure water needed to spin the pelton wheel.  Version 2.0 of the water distribution system was more successful.  Version 2.0 consists of a manifold which evenly distributes the water between the four 1 inch pipes.

Parts List:

  • Permanent Magnet Alternator (PMA)  DC-540  – $229
  • A/C kit for PMA – $29
  • circular rubber gasket – $3.99
  • 5 gallon bucket with lid -
  • grinder disc
  • 45 degree PVC elbows
  • marine goop
  • epoxy
  • various nuts, bolts and screws
  • 200 feet of 2 inch water line – $350
  • 2 inch valve – $19.79
  • 2 inch pipe connectors – $ 2.86
  • 2 inch to 3 inch rubber connector – $11.69
  • short section of 3 inch pipe – $1
  • 3 inch pipe cap – $4.76
  • 4 one inch plugs – $8.24
  • 30 feet of 1 inch water pipe – $18
  • 1 inch to 1/2 inch connectors – $4.28
  • small bits of wood – $1
  • various hose clamps – $5
  • zap straps – $1

approximate total cost: $750

Power output measurements:

valve 1/2 open:  25.6V
valve fully open: 56V

The power bucket uses approximately 1.7 liters per second of water at full power.

On my next visit to the cabin I plan to bring a dummy load and a second multimeter so I can measure the current produced by the system.

Thanks to nefis from the Make magazine blog for his comments:

power output

There’s an output chart for the DC-540 on the Windblue website. A voltage output of 56V corresponds to the alternator spinning at 625 RPM producing 10 amps, generating approx 560 Watts of power.

http://www.windbluepower.com/Permanent_Magnet_Alternator_Wind_Blue_Low_Wind_p/dc-540.htm

and specifically this chart

Planned future improvements:

The creek runs slowly in the summer time which means that I can not run the system at full power without draining the reservoir.  My plan to overcome this issue is to ‘pulse’ the system by using some sort of water level sensor in the reservoir.  When the reservoir is full the system would automatically open the valve, then as the reservoir is nearing empty the valve would automatically close.  My biggest hurdle in getting this modification to work is finding or building a controllable 2 inch valve.

Assembly tips:

Drill holes in the bucket lid to accommodate the shaft and two mounting posts of the PMA.  The circular rubber gasket is placed between the PMA and bucket lid around the shaft.  Apply copious amounts of marine goop around the bolts on the bottom of the lid to stop water from splashing up on the PMA.

The pelton wheel is constructed from an 8 inch grinder disc with 12 ‘spoons’ mounted around the circumference.  The spoons are made by cutting the 45 degree PVC elbows in half.  Holes are drilled in the grinder disc and the cut elbows are mounted using nuts and bolts.  Marine goop is applied to the fasteners to stop them from coming undone.

The water jets are mounted to the bucket via the wood ‘jet aimers’, for lack of a better name.  Holes are drilled in the sides and the bottom of the bucket to allow it to drain.

Assembly images: