Typical Solar PV Off-Grid Power Systems such as the "Solar Power for School PC" design, suitable for remote areas with no utility grid, & capable of adequately powering a small Western home or equivalent village schoolhouse or clinic (1000 - 4000 watts), use fairly high-end & sophisticated components that bring the total cost of the system to $8,000 - 30,000, typically covered by NGO grant funding. At the end of a pair of several day intensive workshops I took at the Solar Living Institute (SLI) in 2008 to learn Solar PV Power Engineering, the workshops PV 190 Design and Install an Off-Grid RE System & PV 290 Off-Grid Systems for Professionals, I discussed with one of my instructors, Alex Aragon, the possibility of designing & evolving a more compact, efficient, economical & portable system that could be more precisely taylored & scaled to a specific set of electrical loads, for example just the laptop computers running during certain hours in the schoolhouse, & an approach which, where no NGO grant funding may be available, would be inspired by, & follow in the footsteps of, the MIT "$100 Laptop" approach, with all components weighing in at around, for starters $500 - $700. Alex rose to the challenge & in a very short while, just in time for SLI's annual 12 acre outdoor Appropriate Technology Expo "SolFest", came up with just such a design, which he demonstrated to quite a crowd attending SolFests' Saturday Conferences Renewable Energy Track during his 2-3 pm talk "[28] Design and Build a Small Off-Grid Solar Power System".

Alex Aragon gives an overview of the whole "PV-in-a-Box" system: Solar Panel; Deep Cycle Battery (in plastic utility box); Charge Controller & Inverter (mounted on plywood); The system provides power, by day via the solar panel & at night via the battery, for a stream or well Water Pump (on utility box cover)
The Charge Controller & Inverter mount over the Battery compartment, with room to spare for the utility box cover; the box itself sports several openings for adequate cooling & ventilation	The Deep Cycle Battery below the Charge Controller & Inverter is also well ventilated. The easy lift-out Charge Controller & Inverter platform makes for easy battery access when checking & refilling Battery water levels
The "PV-in-a-Box" system is hooked up to power a sample device, the Water Pump	The Water Pump starts up & proves an effective water delivery system - "Thar She Flows!"

Alex's detailed electrical schematic of the "PV-in-a-Box" system