Off-Grid Night Lighting

SUBHEAD: Off-the-shelf solar powered system for bedroom lighting for under $1,000.

By Juan Wilson on 14 August 2009 for Island Breath - 

Image above: Bedroom lighting provided by the sun to compact fluorescent fixtures. All photos by Juan Wilson.

After reading Sharan Astyk's article 'Let There Be Light" I thought it was a good idea to share a solution we have employed for night lighting in our bedroom. We do not have the money to install a solar-photo-voltaic (PV) alternative to our KIUC (Kauai Island Utility Coop) grid connection. However we have begin to find solutions to replace KIUC in certain "critical" and achievable replacements for relying on the electrical grid.

Two critical missions are now partially solved: 1) Lighting for the kitchen; 2) Lighting for the garage. We need more power and storage for both. We are not close to providing what is needed for refrigeration or the washer and propane dryer.

But we have satisfatorily solved two important needs: 1) Keeping two frequently used lap-top computers charged all the time. 2) Lighting our bedroom at night.

The computers are quite demanding and required almost $2,000 in PV hardware (with several separate vendors and some requiring some experience with PV. On the other hand the lighting for the bedroom came "off-the-shelf" from

Two items from Amazon are required: a solar panel and storage unit.

A solar panel with PCV frame (brown wooden frame added), controller (inverter and charger not used in this instance).  ($284.98 as of 8/14/09) not including shipping:

To set this system up we attached the solar panels to the included PVC frame system. We have a pretty flat roof over the bedroom, which is an advantage for this situation. We also built a wooden frame out of 2x4s to nestle the panel array onto. This frame allows for three angles settings for the panels (the two solstices and the equinox). If you want specs on the frame we built, shoot me an email at

Image above: Four cables from PV panels coming off roof to voltage controller with line feeding down to PVC pipe in the bedroom. We then used the provided cables and voltage controller to run the PV power down from the roof and to the wall outside our bedroom. I drilled a hole through the wall near where the storage unit would sit inside. We sized the hole to snugly fit a short (1" inside diam.) PVC pipe to handle the cabling.

Image above: Xantrex storage/inverter unit with extension cord to lighting fixtures. Note PVC with cable through wall. [Note: this unit can be used indoors because it uses a sealed AGM type battery for storing electric charge. They do not leak explosive gass as wet-cell (car) batteries can. AGM batteries can even be used tipped on their side.]

A storage/inverter unit ($371.58 as of 8/14/09) not including shipping:

We have learned over the years that PV use requires maintenance. The reality is you are running your own power company, and you have to attend to loads and equipment. We found with the bedroom lighting with this particular hardware rig we can leave the 110v inverter running 24/7, use the lighting at night just as we did when it was hooked up to the grid.

What we cannot due is leave the lights on all the time. We use them to read at night or light the room in the wee hours of morning. For that kind of load this is "care-free" alternative energy.

I have not done a calculation on how long it will take for this unit to pay for itself. I assume we should get at least five years of use from the battery. I figure the real payoff will be on some dark stormy winter night in 2014 when the KIUC grid is down, my wife and I will be snug in bed reading while listening to the raindrops.

In a later article I may will describe our laptop computer charging system.

See also:
Island Breath: Dealing With Chaos 10/7/08

1 comment :

Progress Lighting said...

I really admire people like you who finds alternative to conserve energy and use the renewable ones. After all the fossil fuels have been depleted, we will all resort to renewable energy though we still have reserves for hundred years. But, are we going to wait for it, something might happen if the fossils were already gone.

Post a Comment