Help Evaluate This Solar Panel

767mrN#13
767mrN#13 Solar Expert Posts: 35 ✭
in Solar Beginners Corner #1
NOTE: I bought the panels. Thanks for the input!


These solar panels are on sale. http://www.dmsolar.com/dm15somo2pkp.html

They aren't UL listed and only have an 18% cell efficiency.

Why wouldn't they be UL rated?

Does an 18% efficiency indicate that, at best, these 158 Watt panels will only be storing 28.44 Watts per hour (unless something else further reduces the output)?

Any input you can offer a newbie will be appreciated.
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,590 admin
    #2
    Re: Help Evaluate This Solar Panel

    18% is very good. Ratings for the panels look good too.

    No UL sticker, that is probably why they are half price.

    Check shipping and insurance pricing too. Can add a lot to the costs.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #3
    Re: Help Evaluate This Solar Panel

    Welcome to the forum.

    Those are perfectly normal 158 Watt Monocrystaline panels. The 18% efficiency refers to how much solar they can convert to electrical energy: 18% is a very good rating and quite typical for mono panels. That's a percentage of the 1000 Watts per meter square that falls on them; not a percentage of the panel's rating. This does not mean they will put out 158 Watts: that is a standard test condition rating. Normally output will average about 80% of that (not including controller losses).

    Panels do not store energy; they convert it from visible light to electrical power.

    They are not UL listed but they are ISO 9001:2000 Certified, so you should have no trouble using them in any application.

    Quite a few forum members have these DM panels and are happy with them.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #4
    Re: Help Evaluate This Solar Panel

    The 18% is for 1000w/m2 which is the ideal conditions, they probably produce at peak in good conditions about 77-80% of the 158 watts.

    No UL and most AHJ will disallow there use for a grid tie system.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #5
    Re: Help Evaluate This Solar Panel

    ISO 9001/2000 applies to the safe practices in manufacturing and UL applies to products... Not sure if product would be considered safe with ISO 9001/2000... (Not my end of the world though, just what little I understand about it, I do believe other standards for safety are normally accepted these days, ETL and CE(?)

    You can search here for DMSolar and get some ideas of their reliability, The price has been about that for a while, I tend to recommend purchasing through Amazon, which gives you more recourse if problems arise, but I noticed that the shipping in a bit cheaper now through the DMSolar web site, $96 vs $120 through Amazon.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #6
    Re: Help Evaluate This Solar Panel

    These are inexpensive 12 V PVs. The highest quality competing PVs are about twice the price.

    The Cell efficiency is not particularly important, compared to Module efficiency.

    For a small system, built on a shoe-string, they may be just fine. Who knows just which PV manufacturers may survive in ten or twenty years?

    Have not used these PVs, but was just looking at them for a neighbor's system. This neighbor is on a very tight budget. Shipping can be a killer if one needs two or three PVs.

    Believe member ywhc, Al is using a 140 W version of this PV on a cabin in TX, IIRC. Saw one of his reviews on Amazon today ... ' epsgunner ' , IIRC

    Here is a Thread on the similar PV, here:
    http://forum.solar-electric.com/showthread.php?15880-The-final-piece-for-my-system-panels-12v-or-24v&highlight=ywhc

    FWIW, YMMV, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • Plowman
    Plowman Solar Expert Posts: 203 ✭✭✭✭✭
    #7
    Re: Help Evaluate This Solar Panel

    I have two of these panels. Got one about a year ago, the second one a couple months ago, both from a local distributor. They've been working very well. The two of them are fully charging my two Trojan T-105s without problem. I've seen greater than listed Imp on more than one occasion.

    I plan on getting two more, will probably get them directly from Dmsolar. They're $365 shipped for a two-pack to my location. As far as I know, Renogy is the only other brand that comes close to matching this price for a 12V panel.
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  • 767mrN#13
    767mrN#13 Solar Expert Posts: 35 ✭
    #8
    Re: Help Evaluate This Solar Panel
    Plowman wrote: »
    I have two of these panels. Got one about a year ago, the second one a couple months ago, both from a local distributor. They've been working very well. The two of them are fully charging my two Trojan T-105s without problem. I've seen greater than listed Imp on more than one occasion.

    I plan on getting two more, will probably get them directly from Dmsolar. They're $365 shipped for a two-pack to my location. As far as I know, Renogy is the only other brand that comes close to matching this price for a 12V panel.



    The two panels came in. And the cost was $365. The shipping seemed high, but the panels seemed to be a good deal so I figured it evened itself out.
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