A design spreadsheet I made to explore an idea I have for retro-fitting an eletrical assist system onto existing gas cars. You enter the horsepower and time of the assist, and it figures out the cost and weight. Also, you can add PV panels and it will figure their cost and weight and compute the sun-only charge time.

A design spreadsheet in which you enter the specs for the solar system you need and it tells you the cost! You supply the maximum # of Watts, the number of hours per day and the amount of sun you get.

Using the lifetime of PV panels, their cost, and their capacity, I calculate the cost per kiloWatt hour of PV cells. It turns out to be about one-third of the rate on my electric bill. And it's even cheaper when you consider the subsidization and grid costs! And it's even cheaper when you consider the reduction in health care costs! You wouldn't have to have the government buying asthma inhalers for little kids if we weren't burning so much coal! us solar consumption cost

In this spreadsheet, I explore a graph of the depth-of-discharge versus recharge cycles for a concorde battery. My line of thought was, "So what if you get 5000 life cycles if they're only 10 percent deep?" From the graph, I would much rather discharge 60 percent each time. I still get within 12% of the maximum possible battery life.

In this spreadsheet, I simply put together the components and their costs of a small, practical system with all the cheapest components from all the cheapest vendors I could find!

A design spreadsheet in which you enter the specs for an electric bike such as maximum speed and acceleration. It computes the components and their cost.

Comparison shopping for the cheapest D NiMH rechargeable batteries on the web. You can get a great deal if you buy 100 of them!!

This may be one of the most valuable spreadsheets here! I comparison shop across the web to find the best deals on Concorde SunXtender batteries!

Here I am simply comparing the costs of various charge controllers and inverters. I was hoping to discover a good constant to predict the cost of a charge controller by its wattage.

Here I am simply comparing the values in dollars per Lumen of various DC lighting products on the partsonsale website.