12v lighting

nastynasty Solar Expert Posts: 35 ✭✭
I have a wiring question in regards to 12v lights. Can puck style lights used for under cabinet applications or track lighting be wired directly from batteries to distribution center to a wall switch and then to fixtures directly without the transformer used to step down household current to 12v? If so what size wire would be used and what type bulb would be best? I want to run wiring through wall studs to fixtures. If there is a better way to use a wall switch with 12v lights please tell me. Thanks for any help.

Comments

  • mike95490mike95490 Solar Expert Posts: 9,359 ✭✭✭✭✭
    Re: 12v lighting

    for 12V (ac or dc) these work very nicely.
    http://www.amazon.com/gp/product/B002Q9B1ZQ/ref=s9_simh_gw_p60_d0_g60_i1?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-3&pf_rd_r=1GYQPA56HEAN23JYXVS6&pf_rd_t=101&pf_rd_p=470938811&pf_rd_i=507846 { G4 Base 10 SMD LED }
    chose whichever vendor you like . I have the warm white version, been using one in my office for 3 years now, in a lamp from Ikea.
    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

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  • samuelsamuel Solar Expert Posts: 80 ✭✭✭✭
    Re: 12v lighting

    I'm actually in the process of adding some 12V DC lights to my family's cabin to compliment the 110V inverter powered system. I've installed some lights in the garage already and wired it up with #18 wire used for track lighting installs. I used junction boxes where appropriate and since the set up is currently still pretty small (< 20 watts total) only use a 5 amp in-line fuse to protect the wires - which are attached directly to the 12V bus bars. Here is a bit about the garage LED light install, the cabin is still to come. For the exact details about what I used (product info) here is a DC wiring diagram, the complete inventory, and a schematic/overview.

    For future LED 12V lighting I'm going with this (ordered 3 yesterday): http://www.amazon.com/Screw-Camper-Marine-Voltage-1016ww/dp/B004R0EOZQ (E26 Screw Base 12 Volt Ac Dc 5.6 Watt RV Camper Marine Low Voltage LED Light Bulb) This bulb is also 400 lumen, which is pretty good for the price for the current generation of LED lighting. This bulb is great because there is a very very large selection (price and style) for light fixtures that fit a standard screw-type bulb.

    I'm hoping to give this bulb I high recommendation but I'll have to hold off until I can use it. I've used a 450 lumen daylight 110V Ac LED bulb in a desk lamp and am very impressed with the brightness and quality of light.
  • nastynasty Solar Expert Posts: 35 ✭✭
    Re: 12v lighting

    Samuel
    Thanks for the info I think I will do something like this. For light switches you are using toggle switches. How do you have them mounted?


    Go Pack!!!
  • samuelsamuel Solar Expert Posts: 80 ✭✭✭✭
    Re: 12v lighting

    I'm using standard light switches (used for 110V) and wiring them for the 12V lines. I've mounted them a few inches higher on the wall (in the garage) to keep them separate from the 110V light switches. When I install the next set of 12V lights (in the cabin) I'll update my blog and include some more pictures of the wiring process than I did for the garage. In the garage we used a 3 light switch box that was large enough to contain all of the connections for the three lights in the garage (no junction box). This next install will require the use of a junction box and will be a bit more elaborate and have more options for future expandability.

    12V for our cabin began as an experiment and is now evolving into a bigger and bigger part of our system. When designing a system of any kind, keep the option of future modification in mind. Cheers.
  • bmetbmet Solar Expert Posts: 630 ✭✭
    Re: 12v lighting

    110VAC light switches aren't rated for DC use. How many amps are being pushed thru them?
  • samuelsamuel Solar Expert Posts: 80 ✭✭✭✭
    Re: 12v lighting

    In each switch it is 0.25, 0.25, and 0.5 amp max at 12V. I made the assumption that such low currents would be safe to run through the switches, and have no plans to run currents greater than 2 amps. Should I be concerned? - under what circumstances is the risk of running DC current through AC switches a problem?
  • BB.BB. Super Moderators, Administrators Posts: 32,006 admin
    Re: 12v lighting

    In general, DC sustains arc much better than AC... So, at ~12 volts and above, there is a good chance that even with fairly low current levels, that you may have to replace the light switches every few years (as the contacts eat out from arcing).

    Look at the detail electrical specifications for the different models/brands of switches--you may find some with DC ratings too.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nastynasty Solar Expert Posts: 35 ✭✭
    Re: 12v lighting

    Can regular RV style 12v switches be used?
  • BB.BB. Super Moderators, Administrators Posts: 32,006 admin
    Re: 12v lighting

    If you like their looks, why not.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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