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Post by jeffinseattle on Aug 1, 2019 1:09:27 GMT
Hello Community!
I have an off-grid cabin in a sunny, but forested area, where "all sun, all the time" does NOT exists. Nowhere on my property will panels always be exposed to full sun, grouped together or not because of trees.
So, I have decided to simply hang the panels (7 panels) off the cabin for cost/benefit reasons; result, not all panels will get sun at the same time. While some are getting full sun, others will be in full shade. This would be the case even if they were all clustered together in the ground due to trees and sun movement...so no real benefit to offset the cost of ground installation.
Question - Parallel or Series? Is one or the other better when not all panels will get sun at the same time due to trees, sun movement and panel placement?
Thanks!
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Post by tattoo on Aug 1, 2019 2:04:28 GMT
Hello Community! I have an off-grid cabin in a sunny, but forested area, where "all sun, all the time" does NOT exists. Nowhere on my property will panels always be exposed to full sun, grouped together or not because of trees. I have a cabin that is totally off grid also, Your system is very similar to the one I have other than I do get about 2 1/2 hours of direct sun light on my panels..... I now have 12 of them.....
Before I answer your question we need to know more about what system you have...... You know what CC do you have, how many batteries etc???
Why can't you put your panels on the roof??? On the side is a very bad choice as the angle is way wrong....
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Post by bupkis on Aug 1, 2019 17:12:18 GMT
Question - Parallel or Series? Is one or the other better when not all panels will get sun at the same time due to trees, sun movement and panel placement? Thanks! the simple answer is parallel.
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Post by jeffinseattle on Aug 1, 2019 18:38:01 GMT
Sorry, I thought the tech info would show up...
RENOGY 60 AMP COMMANDER MPPT SOLAR CHARGE CONTROLLER 3x 130ah deep cell (adding a 4th) planing to bury batter box with ventilation Renogy 3x 100w panels - adding 4 more
Thanks Bupkis!
Tatoo - Short answer on roof mount, is snow. I mounted them vertically before (and worked OK), but moved them to test a different location. When I hung them before, they were hinged and tilted out to gatch more sunlight. On my last visit before snowfall, I would lay them flat (perfectly vertical) and then I would get plenty of reflected light...once it snowed. Problem is, 6 months of the year I get no direct sunlight at all, because I'm on a steep north-facing slope.
I will end up with 2 panels facing East, 2 facing West and 3 facing South. Keeping in mind, even though they are facing south...there is no direct sunlight for 6 months.
Other considerations - 102 during the summer, -5 in the winter, only visit about once a month, 168 miles away from home.
Jeff
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Post by jeffinseattle on Aug 1, 2019 18:41:53 GMT
New panels will hang at upstairs window facing W and E and near the car in this pic facing south. Mounting on the roof...they collect too much snow before I come for my next visit...and with no direct sun the roof never melts off. Jeff
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Post by bupkis on Aug 1, 2019 18:54:16 GMT
3 parallel strings, each string with 2 panels.
Series circuit has the same current at any pt (voltage is addative) so if one panel is making 1A then the other panels will be drawn down to 1A unless there are bypass diodes built into the panels or added.
parallel circuits have the same voltage but current is additive, so if one panel makes 1A and another makes 5A then 6A will make it to the controller.
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Post by jeffinseattle on Aug 1, 2019 21:46:24 GMT
bupkis - thanks for that! I had not thought about breaking up the panels into 2 groups. I should total out at 8 then (not 7), for groups of 2. The panels I get (https://www.renogy.com/renogy-100-watt-12-volt-monocrystalline-solar-panel/) do say they have bypass diodes...
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Post by bupkis on Aug 1, 2019 23:34:13 GMT
8 in series, use Voc of ~22 x 8 = >150v max input. Even all 7 in series exceeds 150v.
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Post by tattoo on Aug 2, 2019 1:20:18 GMT
the simple answer is parallel? ? Not really..... What if he had a 20amp CC? ? ?
Hence my question......... I didn't know what he had...... It could have been parallel/series.......
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Post by tattoo on Aug 2, 2019 1:24:23 GMT
New panels will hang at upstairs window facing W and E and near the car in this pic facing south. Mounting on the roof...they collect too much snow before I come for my next visit...and with no direct sun the roof never melts off. Jeff Man your lucky, You get way more sun than I ever thought of getting......... Now you get way more snow.........
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Post by tattoo on Aug 2, 2019 1:25:51 GMT
I had not thought about breaking up the panels into 2 groups. Yep hence my question above.............
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Post by tattoo on Aug 2, 2019 1:57:17 GMT
If it were me I would put several panels on the roof and have several to do what your doing now..... I just added 4 panels that I can cut on when I need them, like on cloudy days and late in the afternoon when the sun is behind the trees......... In direct sun it's a little to much power for my CC even though the CC could handle it but I see no need to try it... So far it has been very helpful.........
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Post by bupkis on Aug 2, 2019 2:04:39 GMT
jeffinseattle, I regret some have to ask questions about stuff you have already provided, I was able to read it! here it is again for others!!! Folks, click the above to see original size, came from main forum page!!
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Post by tattoo on Aug 2, 2019 12:25:01 GMT
jeffinseattle, I regret some have to ask questions about stuff you have already provided, I was able to read it! here it is again for others!!! Glad it showed up for you bird it didn't for me.... But it is there now.......... Also if you seen what he had why did you give him the wrong answer? ? ? Either way you were wrong with your first post......
The best way would be parallel and series........ And should add at least one more panel.....
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Post by tattoo on Aug 2, 2019 12:49:04 GMT
jeffinseattle the problem your going to run into is your panels aren't going to be close together with the way you say you have to set them up....... Because of wire length......
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