noob asking about outdoor walkway lighting set-up?

SystemSystem Posts: 2,511 admin
I guess I'm looking for some quick answers, if a project I'm thinking about is economically feasible. There's a lot to read and digest on solar power and I'd have to brush up on my electrical formulas just to understand what I need to ask, so I thought this may be a fast track to an answer.

I have a lake house with a long, steep (with stairs) wooden walkway through trees and a dock/boathouse at the end. The lights on the walkway are 14 standard socket light fixtures, and I have a mix of CF blubs (too bright) , bug lights (60w) and two LED bulbs. With 14 60w bulbs, the walkway uses more watts than all the lights in the house and would make the lights dim when I would turn on the walkway lights.

My idea is to put solar panels on the roof of the boathouse, and low voltage LEDs to replace all the AC lighting. It would need more than 14 since the lower lumens of the LEDs and we've recently added more stairs. Also, the walkway runs about 150 feet, but the panels and batteries can be a few feet from each other. I'd like to put a photoeye on the system to turn the lights on at dusk until they run down.

What do I need to read to do this and is it under $1K?

Any input is welcome. This is a convenience thing with some added cool factor and I dread when the walkway lights get left on wasting that much power.



  • BB.BB. Super Moderators, Administrators Posts: 30,530 admin
    Re: noob asking about outdoor walkway lighting set-up?

    The most efficient (cost and environmental wise) is to just convert your lamps to LED (or smaller CFL's) that still run on your household 120/240 VAC. Get some motion detectors (top/bottom) of stairs to only turn the lights on when you need them (add a manual switch if you want them on for aesthetics and/or when guests are coming by and the lighting helps them find their way).

    Your first step into solar should be conservation (extreme conservation as generating your own power is 10-20x as costly, on a $$/kWhr basis vs utility power).

    Once you have done the conversion--you can measure your actual power requirements and design a solar system (if you still want) to power them.

    The problem with your system request is that you want them on until the battery runs down.... About the only battery that can run flat--are those small systems with one or two AA NiCADs... Even then, the batteries only last a year or two in the application.

    Larger batteries, on the other hand, have their cycle life defined by how far they are discharged... You may get 1,000+ cycles for a 10% discharge, 500+ cycles for 50% discharge, or 10 cycles for 100% discharge.

    So--large systems need complexity and/or over design to prevent them from excessive battery cycling.

    At this point, it does not make much sense to go into a solar system design until you know how much power you need and how long per day they operate (Watt*Hours). And that would require you to do your conservation first.

    Right now, to power your current lights/usage, you would be talking about a system that cost $10,000's -- also depending on how long you want the lamps on:

    14 x 60 watts x 10 hours per night = 8,400 Watt*Hours = 8.4 kWhrs per night

    (by the way, my whole home with two adults and two kids uses less than that amount of energy--and I have a 3kW solar array)

    14 x 60 watts x 1 hours per night = 840 Watt*Hours = 0.84 kWhrs per night

    That would take about 400+ watts of solar panels to run (depending on where you live)... That would be around $1,000-$2,000 worth of DIY solar.

    Now, convert your lights to 3 watt LED lamps at 10 hours per night:

    14 x 3 watts x 10 hours per night = 420 watt*hours = 0.42 kWhrs per night

    Or, if you put motion detectors on them and assume 1 hour per night:

    14 x 3 watts x 1 hours per night = 42 watt*hours = 0.042 kWhrs per night

    Now, you are down to a 25 watt panel + support stuff... Very doable. Still more expensive to do Solar than Utility power, but at least you are down to $500 or so for the experiment.

    Remember--solar is seasonal and relies on sun shine... For 9+ months out of the year, my Grid Tied 3kW solar system give me >16 kWhrs per day... However, in the winter, I have times when it will generate less than 1 kWhr per day for days at a time (dark winter skies).

    So--you have to decide if the solar will support 100% of your needs, or if you will use other backup power (utility, generator, larger battery bank, etc.) for winter.

    Anyway, you get an idea of what I would go through to do a project like yours.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 8,768 ✭✭✭✭✭
    Re: noob asking about outdoor walkway lighting set-up?

    Get strings of LED holiday lights, repeat as needed. Long strings are only a couple of watts, if you can't stack enough to make 1 long run, use a ext cord, and feed from the middle, going up / down the stairs.

    Runs off 120VAC 24/7, forget wasting $ on a timer they will break.

    If you must play with solar power,
    1, 100W panel,
    charge controller (Sunlight solar lighting controller
    10-amp 12 volt
    1 Deep cycle battery, and
    1, 50-75watt cig lighter inverter for a laptop in a car,
    (powered from LIGHT of charge controller)
    LED light strings (as above)
    should do you for less than an grand.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    gen: ,

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