system for running a few 23W cfls to light a sign

System
System Posts: 2,511 admin
in General Solar Power Topics #1
I love the idea of solar power.
I was thinking about making a system to light a sign every night for 5 hours.
I figure two 23W cfls would be fine.

Two questions.
1) How many Amp-hours does one of these 23W bulbs use?
2) With the answer to that in mind, do you think this system would be adequate?

300W inverter
28 amp/hr battery
20W Solar panel
charge ctrl.
Total: $300

Am I close or way off?

Thanks!!!
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: system for running a few 23W cfls to light a sign

    There was a thread for pretty much the exact question over here...

    You are up around Toronto Canada???? When do you want to power the sign 6-9 months of the year, or year round?

    The 20 watt solar panel is probably too small. And the total cost will probably be 2x (or more) of your first estimate--if you build the system to last (good sine wave inverter, solar panel, battery, charge controller).

    You can get some basic pricing and recommended manufacturers from our host Northern Arizona Wind and Sun (will ship).

    You could get rid of the inverter and use DC LED or Fluorescent ballasts/lights. If you only need power during the summer--you will save on the solar panel costs.

    If this is a short term project (just a couple years)--you can try the less expensive panels and batteries.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #3
    Re: system for running a few 23W cfls to light a sign

    also note that the system you proposed garry will draw at least 20ah per night for 2 cfls and the battery should be at least 2x this so that the battery does not drain beyond 50%. now when it comes to putting power back into the battery you must figure that in the winter months you may only get a few hours of full sun that must supply all that you intend for the lights plus losses in wire resistances, controller, battery, etc. and the pv must be able to supply this in the time available noting that some days are cloudy and a total loss. if you can't get enough pv to keep it up you could supplement with an ac charger once in a while.
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  • System2
    System2 Posts: 6,290 admin
    #4
    Re: system for running a few 23W cfls to light a sign

    The "20 watt" PV will supply a bit over one amp under load in full sun. Thus if you were to get 5 hours of full sun every day, you could count on about 5 AH to replace part of the 20 AH that your lights would use as presently planned.
    Cloudy days would be MUCH lower.
    Wayne
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  • System2
    System2 Posts: 6,290 admin
    #5
    Re: system for running a few 23W cfls to light a sign

    I don't see the need for an expensive sinewave inverter when you're just powering some CFLs, even my ultra cheap 80 watt modified sinewave inverter has no problem running CFLs, plus buying a small unit like the 80 watt I have would be better since you'd have less idle current draw from the inverter like you'd get running a small load on a large inverter
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #6
    Re: system for running a few 23W cfls to light a sign

    Look into 12vdc cfl. I have never used them, and they are bit expensive, but in the net/net it might be more efficient. I agree that a cheap msw inverter is fine, except for any efficiency factor.

    As in most cases, more battery, more panel,

    Icarus
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