used pv questions...

hello to all... first timer here, though i've been reading your forum for quite awhile. I'm looking at getting panels for my rv and found 4 kyocera 51w used panels and as yet undetermined controller for 900 bucks. Since there's no tires to kick, are there other things to look for when looking at used pv's and how does that price sound to you guys? Are there panels better suited to mobile applications than others? Any help greatly appreciated. Thanks, John

Comments

  • Solar GuppySolar Guppy Solar Expert Posts: 1,987 ✭✭✭
    Make sure they are not 2000-2001 manufacture date code ... Kyocera had issues with the conductive tape on these modules

    You can also buy brand new Sun-170 modules for 2.74 watts ( Non-UL , seconds ) from www.sunelec.com so at a minimum use that price point for comparison to used panels
  • mike95490mike95490 Solar Expert Posts: 9,571 ✭✭✭✭✭
    You can also buy brand new Sun-170 modules for 2.74 watts ( Non-UL , seconds ) from www.sun-elec.com


    odd, at http://www.sun-elec.com all I can see is a way to have my PSP and other eGames repaired
    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 ,

  • Solar GuppySolar Guppy Solar Expert Posts: 1,987 ✭✭✭
    opps, thanks Mike, fixed the link www.sunelec.com ... they are also on eBay for the same price.
  • System2System2 Posts: 6,290 admin
    Re: used pv questions...

    Thanks so much for your responses... more questions later but for now just one: how did the neophyte ever navigate new fields before the internet forum?
  • System2System2 Posts: 6,290 admin
    Re: used pv questions...

    Public Library? It's sad but I haven't checked out a book since I can remember...
  • WindsunWindsun Solar Expert Posts: 1,164 ✭✭
    Re: used pv questions...

    While $900 for 200 watts of panel is not bad, it is nothing to scream about either for used panels.
  • System2System2 Posts: 6,290 admin
    Re: used pv questions...

    I'm a novice to Solar, and I'm building a log cabin to live in and I'll use solar,wind and some grid. But just to get a good understanding of some of it. what I did, was I took some solar landscape lights, then took off the batteries, so I have complete solar power. I hooked one up in direct sunlight to my multimeter, it read 2.09, now when I hook two together I still get the same reading. Shouldn't I get double? When I put meter on 20v I get 2.09, but when I put on 200ma I get 41.3 I know I'm new to solar but electricity is supposed to be your friend. Could someone clear this up for me. I thought it might be my wiring sequence, so I wired from the lights pos. to neg., pos to neg, then to meter and got less.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: used pv questions...

    ken ray,
    can't say for sure, but it sounds like you didn't wire it properly. in any case, why take apart all of those lights just to get the solar cells as you can buy them cheaper in a small pv than what it costs for what you're doing?
  • mike95490mike95490 Solar Expert Posts: 9,571 ✭✭✭✭✭
    Re: used pv questions...

    Any little bit of shadow will shut down the solar output, one partialy shaded panel, will shut down an entire string.

    each individual cell generates about .5 V in the yard lights, they layer a row of cells, stacking them a little like shingles, bottom edge of one, on the top of the other, till they have the right voltage for their light.

    I've had many of them, and they have a pretty high failure rate, and if you open one up, that could kill it to. I suppose they are made from scrap chips off larger arrays. Look at them hard enough, and they can crack, and you will never be able to see the defect.
    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 ,

  • System2System2 Posts: 6,290 admin
    Re: used pv questions...

    I apprec. the info. but call me a skeptic. I don't know, and don't claim too. I still can't getover the fact of a reading of 2.09 in a 2 1/4 inch sq. That is 2.09 volts is it not. If it's not right tell me. And I'm buying the lights at $1.37 each.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: used pv questions...

    how many cells do you see in each light? i'll bet it's 4 because 4x.5v=2v. yes, it's a bit higher because of the open circuit voltage always being a bit higher than what it is under load. you got them cheap enough for sure, but it still won't be easy getting 36 cells in series. the 41.3ma is the short circuit current and the max power current will be lower and i'll guess around 36ma so .036a x 17v (approximated max power voltage)=.612w for the whole panel if that's what you would call it. you will need many of these to have any appreciable power, but you probably now have many aa batteries you can now charge not to mention many white leds to play with.
  • System2System2 Posts: 6,290 admin
    Re: used pv questions...

    Niel thanks alot. Let me ask, if I've got 4 cells in each can't I put 3 rows of 3 to get my 36? And is 36 a top number or can it be 72 or 108 if I have 4 cells in each? In the top of my light their are 4 rows connected by 1 on the ends, I assume these are my cells.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: used pv questions...

    3 rows of 3 what, cells or 3 rows of 3 sets of 4 in series? for 36 cells that would be the equivalent of 9 of the solar lights as each has 4 so 4 x 9 = 36. yes, you can make it to whatever you like and series/parallel them too, but 36 is a standard to allow for 12v battery charging.
  • System2System2 Posts: 6,290 admin
    Re: used pv questions...

    3 rows of 3 lights. (4 cells each x 9 lights = 36.) But if I could go 3 rows of 9 lights ea. Could I get 108, and would that be 108 / 36 = 3 sections at 12v sections each, on 1 panel So do I wire them 1 after the other on 9, then those 3 into 1?, all of or more on 1 @ 2' x 4' panel.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: used pv questions...

    if you can mount that many then each row can be paralleled for higher current. i don't know what use you would have for 36v at about 36ma with all of them in series, but it can be done. with series/paralleling you will have 12v at about 108ma.
  • System2System2 Posts: 6,290 admin
    Re: used pv questions...

    Is 36v alot? I will try a tv,refrig,compu or whatever it will handle.
  • Solar GuppySolar Guppy Solar Expert Posts: 1,987 ✭✭✭
    Re: used pv questions...

    Well, best case its 12 watts peak in full direct sun , so adjust you expectations accordingly
  • System2System2 Posts: 6,290 admin
    Re: used pv questions...

    are you saying that 36v is only 12 watts? if that is the case I'll probably forget this solar alltogether. but I hooked 10 lights in series today, and got 21.8v, to me that was great I think.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: used pv questions...

    the fact it is 36v is only half the reason for the wattage as it is the voltage x the current. 12v x .108a=1.296w and 36v x .036a=1.296w and is far lower than 12w. note the 12v operation is the same wattage using a series parallel arrangement as all in series would be, but 12v allows for more usable current at a more common voltage. few items are made for 36v operations excepting those power wheelchairs and your panel won't even be in the same ballpark to meeting its needs.

    it appears that you, along with many others, seem to have a misconception of electrical power. many think it's easy and cheap to produce on an individual level and it most certainly isn't. producing power via solar is even higher in cost and takes an appreciable amount of room for its generation. with a pv made up of those individual solar lights you could have a good trickle charger for a 12v battery and it would represent about 1/1000th of the ah of a typical battery with 100ah of capacity.
  • System2System2 Posts: 6,290 admin
    Re: used pv questions...

    I'm confused, but not hard; right? Iffff a single cell is .5v, and 1 of these lights puts out 2.29v then why is it not possible to make a energy producing panel from them? I've read where people are taking 36 single cells to make a panel that produces 18v, and that seems to make them happy. I can't see the difference, in what they are doing and what I want to do. Except for the fact of having to use less to gain more. Please simplify this for me. Anyone
  • Solar GuppySolar Guppy Solar Expert Posts: 1,987 ✭✭✭
    Re: used pv questions...

    Here is an example, using the solar light tops you want to use:

    Voltage TIMES Current is the wattage ... so the little solar cells lights have 2.2 volts at 0.03 amps, that is 0.066 watts , run it for 1 hour and you have 0.066 watt/hr

    Now lets think of something to try powering like a common standard 60 watt light bulb everyone knows , how many solar top panels do you need?

    That happens to be 0.5 amps at 120 Volts = 60 watts

    so you would need about 30 of these solar lights all wired in a series , that will make 120 Volts DC @ 0.03 amps = 3.6 watts

    you need 60 watts for the Bulb, so you need 17 of these 30 in series strings

    Grand total would be 17 TIMES 30 or 510 of this solar lights to power a single 60 watt load

    Or you can go buy a 65 watt solar panel for 357.00 http://store.solar-electric.com/kykc65wasomo.html

    vs your build it yourself with solar light for ~1.30 each or 663.00, plus you have to assemble everything

    All your answers an in this post ... if your confused, just keep reading it over and over and you'll get you answers
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