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Post by swbls12b on Jan 2, 2017 15:00:40 GMT -8
lets say you are building an off grid set up, mounting space is not an issue. Is there any advantage to using lower wattage panels? My thought is, seeing as higher wattage panels are cheaper per watt, why not use fewer panels to charge batteries.
BTW, if my question does not make sense it's because I'm a total noob.
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Post by jsb2000 on Jan 2, 2017 17:00:15 GMT -8
I can think of a few reasons why someone might opt for having more panels at lower power versus less at higher power.
One might be if there's the possibility of the panels being fully or partially shaded. Depending on how much of a panel gets shaded, you could lose a good chunk of power. The less panels you have, the greater the loss.
Another might be the possibility of losses due to damage. Sort of like the "having all your eggs in one basket" syndrome. If a rock or hailstone takes out one of your five panels, no big deal. However, if it takes out one of your TWO panels...uh oh.
Finally, having more panels might allow you to point various ones in different directions to maximize output. Or spread them out.
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Post by swbls12b on Jan 2, 2017 17:43:05 GMT -8
Didn't think of those. Shading is not an issue. So are there any American made lower wattage panels? 100 - 150 watts?
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Post by jsb2000 on Jan 3, 2017 4:34:50 GMT -8
So are there any American made lower wattage panels? 100 - 150 watts? Yes, there are. Google is your friend. Although the results show panels above the range you specified, if you go to the websites of the manufacturers, you'll find that many also make 100 - 150 watt panels.
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Post by swbls12b on Jan 7, 2017 9:23:14 GMT -8
I've done that search a number of times and still don't come up with what what I'm looking for. Oh well, I guess I will use large panels. Thanks for your help.
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Post by johann on Jan 29, 2017 16:55:13 GMT -8
I have Renogy 100 watt mono crystalline panels for 3 years and my system is growing. There are a few points you need to check.
Some manufacturers and panels are flybys ( here today and gone tomorrow) companies and sellers that sell flyby panels. Look at the history of those panels and companies. I started to buy renogy panels 3 years ago and they still sell the exact model, size etc so I do not have to make any modifications to my system if I add panels down the road. A 100 watt 12 volt panel can be handled by myself at roughly a little smaller than 2 feet by 4 feet and the weight is not much either if I am in need to get those on the roof by myself . I can use them in a 12 volt system, or I can put them in series in a 24 volt system or even a 48 volt system. You may start out having a 12 volt system and as your system grows the need to switch into a 24 or 48 volt system may arise. I can take 1 or 2 panels with me to go camping or for any other needs.
The more panels you have the more interconnect you have also and the more problems you could have with connections. But, I can just disconnect the bad panel or connector if there would be one and I do not lose much power and I can go on my business until I get a replacement.
One more thing, big panels usually carry a big freight charge or a special handling charge for shipping them.
A lower wattage panel up to 150 watts is a 12 volt nominal panel and any higher wattage panel is a 24 volt nominal panel.
Be careful when buying panels for off grid. Most bigger/higher watts panels offered are for grid tie and have less cells or a lower voltage and may not be able to charge a battery since the voltage is to low.
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