New to Solar...my proposed system...

EAdamsEAdams Solar Expert Posts: 34
I have (4) Northern Tool 15w 17v 1amp panels for 60w 17v 4 amps. I ma starting with this and will eventually add 3 more. For wirimg from the panels to the house I have 12g low voltage landscaping cable. It is rated for 300watts. I am going to run it into my room to a 120v 20amp light switch (PV array disconnect). On the other side of the switch is the 7amp Northern Tool charger, then batteries. I plan on using 12v off the batteries to power 3-5 12v lights within my house for emergency lighting when power fails. Thats about all I plan on using it for. Maye charge a cell phone off a 12v charger.

Will this system work fine? I have very little in $$ to spend and I already have all but the batteries bought.

Comments

  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: New to Solar...my proposed system...

    How far is it from the PVs to the switch and then to the batteries?
    what batteries do you have?
    I assume that this is an independent system and you do not have a 120v charger in the plan. am I correct?

    Eric
     
    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,
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  • EAdamsEAdams Solar Expert Posts: 34
    Re: New to Solar...my proposed system...

    Estimated 35-45ft from closest sunny location for panels to my battery room. No batteries yet, posted that in another thread. This is a 100% independant system. Will be used for emergency lighting only.
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: New to Solar...my proposed system...
    EAdams wrote: »
    No batteries yet, posted that in another thread. This is a 100% independant system. Will be used for emergency lighting only.

    I won't chase threads all over, so I'll respond to your first post.

    Your 4 PV's, (60W total) will need a 3 or 4 stage charge controller to prevent overcharge of your batteries.

    Your charging voltage will vary from 13V up to 16V when the batteries are in an Equalize cycle. Not all 12V gadgets will take that, all are good up to 13.8V (automobile charging voltage)
    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 ,

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: New to Solar...my proposed system...

    with my addressing of the wire and its length only i find it outside of our normal range we consider to be good. losses over 3% we consider as bad and the #12 at 35ft will give a drop of 4.28% and 45ft will give a drop of 5.51%. wire isn't rated for wattage, but is rated for current and as the voltage rises the wattage it can take also goes up. if using #10 for 35ft it would have a drop of 2.7% and for 45ft it will have a drop of 3.47% with 40ft at 3.08%. you can still use your system with higher losses as that's up to you, but understand that low voltage dc power doesn't travel well over distances.
  • EAdamsEAdams Solar Expert Posts: 34
    Re: New to Solar...my proposed system...
    niel wrote: »
    with my addressing of the wire and its length only i find it outside of our normal range we consider to be good. losses over 3% we consider as bad and the #12 at 35ft will give a drop of 4.28% and 45ft will give a drop of 5.51%. wire isn't rated for wattage, but is rated for current and as the voltage rises the wattage it can take also goes up. if using #10 for 35ft it would have a drop of 2.7% and for 45ft it will have a drop of 3.47% with 40ft at 3.08%. you can still use your system with higher losses as that's up to you, but understand that low voltage dc power doesn't travel well over distances.


    What would I lose over that distance considering I am sending 17.Xv, 60watt, 4amp?
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: New to Solar...my proposed system...

    that 17v vmp is still for a 12v system as the voltage of the pv will get sucked down under full load. no need to quable over a few volts here or there as the current will set up a set loss in voltage given the resistance of the wire.
    although most installs do not do this as it's not going along with the nec, but i'd double the wire. use one pair of your #12 wires as a positive and another set as the negative. the equivalent gauge will be about #9 when 2 # 12s are used and you will have with a 45ft run of this doubled-up wire to give you a 2.44% drop. you aren't feeding this to the grid and is just a simple solar setup for emergency lights and such so imo the heck with the nec ruling about doubling your wires as it is imo no different than having a stranded set of wires present, but is seperated by insulation and combined by you. i do not take any responcibility for you doing this though as i'm saying what i'd do and is my opinion.
  • BrockBrock Solar Expert Posts: 639 ✭✭✭✭
    Re: New to Solar...my proposed system...

    Basically not using a mppt charge controller and using the #12 wire at that distance you will be lucky to get 30 watts to the battery.

    You have to start somewhere and I think you’re on the right track. I have just found over the years skimping on the wire from the array to the batteries is like taking one of your panels out of the look, that is an expensive way to loose it's power. In some case upgrading your power lines can add more then adding another panel. You can always add a second #12 wire later.
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: New to Solar...my proposed system...

    naw, it won't be as bad as losing a pv for he will lose a few watts over what it would've been if it was connected directly at the pv with no wire losses, but i don't think it'll be bad enough to take it down that far just because of the voltage drop. he most likely won't see the 60w from those pvs anyway as they tend to be a bit overrated. mppt does help, but would he opt for an mppt controller for those small pvs? i guess that would depend on if there will be any future pvs to be added in a real power range as that many 15 watters would be difficult to mount for starters and far more expensive per w in the longrun.
  • BB.BB. Super Moderators, Administrators Posts: 32,804 admin
    Re: New to Solar...my proposed system...

    Also, put the solar charge controller next to your batteries--least voltage drop and most accurate voltage measurements (for best charging). Also, you will want the remote temperature sensor (if available for the controller you are looking at).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • EAdamsEAdams Solar Expert Posts: 34
    Re: New to Solar...my proposed system...

    K...I'll try the double run on the 12g wiring (1 pos, 1 neg) and go that direction. It was the largest diameter wiring of that type I could find and I have 100ft of it jic. Looks like this is a Just-in-Case situation.
  • EAdamsEAdams Solar Expert Posts: 34
    Re: New to Solar...my proposed system...

    PIc #1, inside board. PV disconnect switch, charger, and 350w inverter.solar1.jpg
  • EAdamsEAdams Solar Expert Posts: 34
    Re: New to Solar...my proposed system...

    Panels Back
    panelsback.jpg

    Panels Frontpanelsfront.jpg
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: New to Solar...my proposed system...

    when you mount them, try to keep them at least 6 inches off of the surface of whatever you mount them on, ie roof. also try to aim them south and you can determine south by the middle of sunrise and sunset times for the closet city or town you can get to yours if not yours. the elevation angle can be your latitude or your latitude +15 degrees to obtain better winter collection without compromising the summer much. even better yet would be an adjustable mount so that you can have at least 2 angles that you optimize them to depending on the time of year.
    think of adding fuses and shutoff switches for a bit of protection and maintenance work.
    i have to add that i don't know if the pvs are protected from draining off the battery during nightime conditions. some controllers will stop this flow and some pvs have blocking diodes and i don't know if you have any of these protections from draining back.
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: New to Solar...my proposed system...

    These look like Amphorous panels (rows of parallel hairlines across the array) and are subject to about 10 % degradation per year.
    Or I'm mistaken. Someone else look at them too ?
    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 ,

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: New to Solar...my proposed system...

    you win the cigar mike. i don't think they'll quite lose 10% every year though. now you need to come pick up the cigar.:roll::p
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: New to Solar...my proposed system...
    niel wrote: »
    now you need to come pick up the cigar.:roll::p

    If I can just reach it with my toes .
    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 ,

  • n3qikn3qik Solar Expert Posts: 741 ✭✭
    Re: New to Solar...my proposed system...

    Eric welcome to the forum.

    I had a set of the Harbor Freight panels on the shed roof for 6 months. They did not lose any noticeable power output.

    Is that inverter going to be hookup to the battery all the time? The standby draw could be high on it.

    If the inverter is not connected to the battery. Only when there is a power failure. I think the wiring losses are of no concern as the draw will only be to float charge the battery for the most part. When and if there is a power fail, it will take just a little longer to recharge the battery.

    With being on a budget, I would like him to spend money on some fuses and disconnects/switches and upgrade the wire latter.
  • EAdamsEAdams Solar Expert Posts: 34
    Re: New to Solar...my proposed system...

    Sorry for the absense..hd crash. Nope, the inverter will not be hooked up 100% of time. Only in a emergency adn then only if I really need it.

    n3qik wrote: »
    Eric welcome to the forum.

    I had a set of the Harbor Freight panels on the shed roof for 6 months. They did not lose any noticeable power output.

    Is that inverter going to be hookup to the battery all the time? The standby draw could be high on it.

    If the inverter is not connected to the battery. Only when there is a power failure. I think the wiring losses are of no concern as the draw will only be to float charge the battery for the most part. When and if there is a power fail, it will take just a little longer to recharge the battery.

    With being on a budget, I would like him to spend money on some fuses and disconnects/switches and upgrade the wire latter.
  • EAdamsEAdams Solar Expert Posts: 34
    Re: New to Solar...my proposed system...

    They are amphorus. Was told the only noticable loss was in teh first year then they stabalized. 10-20% (so I was told). Heck at that price just add 1 more panel to make up on the loss + a bit.
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