solar backup lighting advice

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katet1919
katet1919 Registered Users Posts: 2
I have posted a picture about the lighting system I am going to install in my house. My problem  is that Im not sure if I should do a 24 volt system or a 12 volt system. 

Any advice would be great. Everything is in the picture..
thanks in advance

PS YES  I know i got the solar charger red and black wrong on the pick. .. OOPS.

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  • Johann
    Johann Solar Expert Posts: 245 ✭✭✭
    edited May 2016 #2
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    What do you want to power when the grid goes down?
    Only lights? If it is only lights that you want when the power goes out, why not use a emergency light that could be bought at hardware stores like lowes hardware.
    Or , use a UPS (uninterrupted power supply)

    That dimmer in that picture is not the best. I went through 2 of those where one stopped responding and the other started to smoke.  I got 2 of those dimmers on the same  circuit and if I dim both of them ,  then both of them will have a flicker which makes me believe that they feeding back at a frequency to each other. It does not flicker with full brightness. One time I had 14 some volts on the circuit and that dimmer did not like it, it made the LED strip like you pictured blink in 1second intervals to on and then off again. When I reduced the voltage to about 13 volts the LED lights turned back to normal again.

    A while back, I seen a 24 volt version of those LED strips which could save you from having to buy a step-down converter.


  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
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    Why not just buy a normal off the shelf LED emergency light?

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • katet1919
    katet1919 Registered Users Posts: 2
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    none of that gives me any advice to go with 12 volt or a 24 volt system. 
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
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    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
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    12V is for limited size systems.  The wire gauge/Voltage loss requirement is the deciding factor.    The higher the loads and the longer the runs, tend to push more toward 24V or higher.
     But first loads have to be calculated.  Can you use 16 ga lampcord  or do you need 8ga wires for a 300' run ???
    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

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
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    Most emergency light systems use 12 volts. So....

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • Johann
    Johann Solar Expert Posts: 245 ✭✭✭
    edited May 2016 #8
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    katet1919 said:
    none of that gives me any advice to go with 12 volt or a 24 volt system. 
    Since none of it,  is a advise YOU DID NOT wanted to hear or agreed with it, just go ahead and buy a flashlight, maybe this advise will help you.
    This way you have at least a light when your grid goes out.

  • Tigelowe
    Tigelowe Registered Users Posts: 9 ✭✭
    edited May 2016 #9
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    Hello Katet,

    I have a similar setup and went with 24 volts due to 120 feet from the batteries to the '24->12 volt converter'. I not only run my under-cabinet kitchen lights, but my Cradlepoint router, Synology NAS, Security DVR and IP cameras. 24 volts can use a smaller gauge wire carrying half the current, but the same Watts, for longer runs.

    I would expect you will need a DC-DC converter (24->12 or 12->12) either way you go. The voltage on the batteries/charge controller will fluctuate widely. My 24 volt system goes from 24.8 in the morning to 28.5 during absorption charging daily. So, you could expect a 12V system to go from 12.4(or lower if power is out a long time) to 14.3(or higher). Most DC-DC converters have a wide input range and a steady output. If you don't use a DC-DC converter, make sure your LED lights have a wide operating voltage.

    -Joe