Go ahead, call this a stupid question. DC or AC to lights?

ILFEILFE Solar Expert Posts: 364 ✭✭
I live in a rural area. We just completed a "starter" off-grid PV system. Now, my wife asking me if I can run wiring to an "outside kitchen area", about 30 meters from the main house, where the solar array, controller, and batteries are located. They system, primarily, will run DC appliances, lighting, phone charging, and some electronic devices.

My question is, should I just run a fairly large two-conductor wire to feed the lighting there and keep it DC? Or, should I run it through the inverter and have 240vac lighting?
Paul

Comments

  • BB.BB. Super Moderators, Administrators Posts: 32,611 admin
    Re: Go ahead, call this a stupid question. DC or AC to lights?

    How much current? A few Watts for LED lighting... DC wiring will be ok. More than that, 240 vac would be a better choice.


    So how many Watts or amps at what dc voltage?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Go ahead, call this a stupid question. DC or AC to lights?

    As Icarus always says " Loads always grow over time" so she asked you to start with a few lights then.... an appliance or 2.
    Now what?

    You will find all your work needs to be upgraded.... so best to ask the question(s) now and plan for the most she will ever want to have out there.

    keep us posted.
     
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  • ILFEILFE Solar Expert Posts: 364 ✭✭
    Re: Go ahead, call this a stupid question. DC or AC to lights?

    Sorry, guys.

    The array is 300 watts. Living at 13 degrees north latitude, so sun hours isn't a problem here, for sure. Only place I ever lived, where I could get sun burned by breakfast time.

    Good idea to ask what else she may want out there. Not really sure I want to ask, though. :D
    Paul
  • RandomJoeRandomJoe Solar Expert Posts: 472 ✭✭✭
    Re: Go ahead, call this a stupid question. DC or AC to lights?

    How easily available are the different lights (and anything else you might want)?

    I started out with a 12V system because of my ham radio gear, and initially thought I'd use some DC lighting but DC bulbs were ridiculously expensive compared to the mass-produced AC versions. They are also much harder to find. I can buy AC light bulbs at just about any store in town, but the DC ones are only going to be at specialty places like RV shops (for lots of $$$$) or online / mail order.

    That said, I do have a preference for using voltages that don't bite you, especially in an outdoor setting! :) 12V is far more forgiving than 240V.
  • ILFEILFE Solar Expert Posts: 364 ✭✭
    Re: Go ahead, call this a stupid question. DC or AC to lights?
    RandomJoe wrote: »
    How easily available are the different lights (and anything else you might want)?

    I started out with a 12V system because of my ham radio gear, and initially thought I'd use some DC lighting but DC bulbs were ridiculously expensive compared to the mass-produced AC versions. They are also much harder to find. I can buy AC light bulbs at just about any store in town, but the DC ones are only going to be at specialty places like RV shops (for lots of $$$$) or online / mail order.

    Living in a 3rd world country, one learns there are many things that are different here. Quite often, they are much cheaper as well.

    Anyway, I purchased four (4) each, 12vdc, 15w bulbs, for $2.00 each. They did not have any lower wattage 12vdc bulbs available.

    Most people in that area run simple 12vdc lamps, and connect them directly to a battery. These lamps, exactly like the one shown below (I just priced at over $21.00 AUS on an old eBay auction), will cost no more than $4.00 USD here.

    Attachment not found.



    In the area where I have just completed my first two projects, there are no utilities, no nothing, in fact. So, most everyone has batteries for temporary power, primarily for running 12v lights (similar to the one pictured above) in the evenings.

    Actually, I came up with an idea to go with similar 12vdc LED lighting, while buying the fluorescent bulbs. However, they did not have any available.

    RandomJoe wrote: »
    How easily available are the different lights (and anything else you might want)?That said, I do have a preference for using voltages that don't bite you, especially in an outdoor setting! :) 12V is far more forgiving than 240V.

    Knowing that I am working with some form of electricity, more than 30 kilometers from the nearest (sub standard, at best) hospital, also makes me feel a bit better as well - knowing it is 12vdc rather than 240vac.
    Paul
  • GodfreyGodfrey Registered Users Posts: 1
    Re: Go ahead, call this a stupid question. DC or AC to lights?

    I would run every thing through an inverter to minimize line loses
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Go ahead, call this a stupid question. DC or AC to lights?

    i'm going to agree with godfrey in going with an inverter on his 1st post here and welcome.

    i will add to it though that it may not be bad to have one or 2 lights operated from dc power in order to shutdown the need for the inverter under very light load conditions. (nightlight or reading light only on) this would allow for eliminating the operational losses of the inverter, but would mean more wire though and i'm not sure how you would feel about running that much in wire. at least being light dc loads the wire gauge will not need to be very heavy duty.
  • westendwestend Solar Expert Posts: 46
    Re: Go ahead, call this a stupid question. DC or AC to lights?

    !2v DC lighting is not that difficult, anymore. These are two fixtures I built with frames from the dollar store. Each fixture with 48-SMD1215 panel cost $3.75 and outputs 120 lumen using 3w,
    IMG_0005-23.jpg

    The LED's are operated on system voltage varying from 12.2 V to 14.6 V. I have them connected using 14 AWG with small runs, the largest being 20'. I used the 14AWG because I have miles of it and no efforts were made to calculate line loss since it is miniscule and the SMD LED panels operate on very small current, less than 250 milliamps.
  • ILFEILFE Solar Expert Posts: 364 ✭✭
    Re: Go ahead, call this a stupid question. DC or AC to lights?

    Thanks, guys.

    I tried to find some 12vdc LED lights here, but that seems to be a difficult task. I have not given up on it, though.

    I did find some fluorescent lamps, 7 watts, to replace the 15 watts bulbs in the lighting circuits.

    westend, where did you buy the LED lamps? Perhaps, from a company that would ship overseas? I have no problem in purchasing lamps from abroad, if necessary. I am in the process of having an order shipped from wind-sun, to me.


    @ Godfrey & neil: I would go with an AC inverter, but, for the moment, we have no AC appliances there, with the exception of a single stand fan that I use while I am working there. (I have one large inverter that is from another project. I took it to use there. It is a modified sine wave unit, anyway, and am only using it on a temporary basis to power the fan.) It is not used for any other reason.
    Paul
  • ILFEILFE Solar Expert Posts: 364 ✭✭
    Re: Go ahead, call this a stupid question. DC or AC to lights?
    ILFE wrote: »
    Most people in that area run simple 12vdc lamps, and connect them directly to a battery. These lamps, exactly like the one shown below (I just priced at over $21.00 AUS on an old eBay auction), will cost no more than $4.00 USD here.

    I just found more of these for $2.50 US, each. I guess I should export them to the US and Australia, for the money they charge for them abroad!
    Paul
  • BB.BB. Super Moderators, Administrators Posts: 32,611 admin
    Re: Go ahead, call this a stupid question. DC or AC to lights?

    Watch how well the LED's last... Inexpensive units use those Tx/x plastic LEDs with the pair of wires coming out the bottom.

    In general, white LEDs are driven with a lot more current than normal red/green/yellow indicator LEDs. And the plastic cases of the LED's are very poor at getting heat away from the LED junction. And they tend to turn brown/black after a few hundred hours of operation (burn the plastic/phosphors).

    Better LEDs, in general, have the flat square style LED mounted to a metal backing (to get rid of the heat). Before you buy a lot of these LEDs, get a some time (months, 1 year or more) on these LEDs and see how well they last.

    Not saying yours are good or bad--I cannot tell from your picture. But good/bright LEDs need to have good heat sinking (generally a fair amount of metal heat sinking). Heat is the enemy of LEDs.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • zonebluezoneblue Solar Expert Posts: 1,218 ✭✭✭✭
    Re: Go ahead, call this a stupid question. DC or AC to lights?

    Definately go led, for one thing give them a bit of whack and they wont disintrgrate.. sending small amounts of mercury showering.

    I also made ours from low cost mail order parts.

    See: http://www.zoneblue.org/cms/page.php?view=led-lighting

    The advantage of making your own is:
    - that they can be tailored to run off your system voltage, eg 24volts
    - you can seperate the driver from the heat source, enhancing driver life.
    - its cheap, and fun!

    However phillips (and others) are aggressively marketing std ac LEDs that are in fact pretty decent quality.
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


  • ILFEILFE Solar Expert Posts: 364 ✭✭
    Re: Go ahead, call this a stupid question. DC or AC to lights?

    No doubt, that I should go with LEDs. Problem is, I will have to order them from abroad, OR, convert the current lighting to 230vac, in order to do so.

    One problem with living in a third world country is availability of items. Unfortunately, conveniences we appreciate in the west, we do not necessary have here.

    Sometimes, when ordering items from abroad, you may receive them; other times, you may not. In many cases, it is the flip of a coin.
    Paul
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