Root Cellar Light

The Problem

Front of the barn. 5W solar panel visible
Iron Rod Farm has a barn on the property, which — although very close to power lines — does not have power. Hooking it up to grid power would be surprisingly expensive. This barn contains a large root cellar in the rear, and originally a flashlight was used to provide illumination in the cellar. However, that was a dim and inconvenient solution — since one hand held the flashlight, only one was free while stocking or removing vegtables.

The Solution

Calculation of hours of sun experienced
Because of the cost associated with running wall power out to the barn, the small amount of time the light would need to be in operation, and since the front of the barn faced roughly south, a solar-based system was chosen.

Source: Gaisma.com

Excel spreadsheet used in design of the system
A small solar system was designed using a 5W monocrystalline solar panel on the front of the barn, two small 7Ah SLA batteries, and a 5m string of LED lights.

Blurry picture of the interior of the root cellar
This provided about 1500 lumens of light at approximately eye level along the length of the cellar. The specific height was chosen for maximum illumination of the three upper shelves. The power usage was designed for a couple hours of culmulative illumination each week during the winter, with slightly higher usage in the fall, when vegtables and fruits were being stocked and organized in the cellar.

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