Open Source PV System

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December 2017 - Completion Walk-Through

  • After testing various loads including internet, lighting, washer, dryer, hydronic pumping, water pumping, macerator lift pump, computers, refrigerator, freezer, vaccuum cleaner, microwave oven, cutoff saw and power tools, and other various appliances - the working system is this:

See also final system diagram.

Cost of Electricity Production

Temperate Zone Case: OSE Headquarters Results

HintLightbulb.png Hint: These numbers are very important. Study them to understand the true cost of PV. It is essentially free over a lifetime of use

  • Assume 6 hours of sun and 20 year lifetime for the 3 kW array
  • Cost total was $1800 for the panels, $3K for balance of system.
  • Take 20 years * 3kW -> 131,000 kwhrs.
  • Conclusion 1: For $3000, we get 131,000 kwhrs, or a cost of 2.3 cents per kWhr.
  • Conclusion 2: If extend to 50 year life with nearly double the electricity, decreasing 0.5% per year - we get down to about 1.2 cents per kWhr. This is close to free. See Lifetime of Solar Cells.

Sahara Case

  • If we are in the Sahara, it is 8.5 hrs of sun instead of 6 ,lowering cost to 1.1 cents per kwhr
  • Lifetime is 80% of initial power at 20 years, so on average it is 90% of rated value. So really 1.2 cents per kWhr in the sahara. But, that means we have 30 more years practically - between 80-50%, or 65% on average. Therefore, another 181000 kWhr - so price goes down to about 0.5 cents per kwhr over a 50 year life.
  • Thus, the practical cost in Maysville could be 0.8 cents per kWhr over a lifetime. Much less than coal or nuclear.

Hydrogen Production

  • Hydrogen production takes 41 kWhr/kg by electrolysis. Hydrogen energy equivalence is 1 kg hydrogen to 1 gallon gasoline equivalent when burned in internal combustion engines.
  • The cost of hydrogen production is $4 per kg if we consider 10 cent per kwhr standard costs of commercial PV energy. But, it is 40 cents per gallon equivalent if we use open source photovoltaics like in our Seed Eco-Home.
  • This means that we need data right now - on a full system from PV to hydrogen engines.
  • Can start with industrial hydrogen bought off the shelf, with multifuel test engines via the Engine Construction Set.


  • 24-12 step down - [1]
  • 240V-24V charger - from doggy line backup line - [2]

Seed Eco-Home

Working Documents





Note: shipping for $1300 worth of panels (3kW) was $500 for $1800 total. $0.43 per watt solar panels, and price continues to drop.



  • Width: 40.25"
  • Height: 48"
  • Depth: 17.5"

Electrical Panel

Part Library

Visual History:



Initial Testing 2016

FB Post

Electrical Plan - Seed Eco-Home


Faculty House 2015





  • Fuse - glass, 250V,F25AL - 6mmx30mm - [100 Pcs Glass Fuses 25A 250V 6mm x 30mm Fast Blow Skywalking]



Industry Standards for a 3kW Off-Grid PV System

Not Installed

  • $13k - [3]
  • 3000W kit for sale with batteries and inverter. No racking/mounting. - $8200 - [4]
  • 3kW kit - panels + power center. No bats or racking/mounting. - $9100 - [5]
  • $8k without batteries - [6]
  • 2.4kW, no racking/mounting, nickel-iron batteries - $13.4k


  • 3000W - $14k - [7]
  • 3000W $18k - [8]

Not Off-Grid

  • $9-11k typical for 3kW fully installed - [9]