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SOLAR help needed


rbertalotto

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I need someone to look at what my solar system is reporting.

Setup:

(3) 140w / 12v panels, flat roof mounted

4' / 10g wire run from each panel to junction box on roof

from junction box 

15' 4g welding wire to controller (15' each leg , +/- total 30')

Bogart SC2030 solar controller

Bogart Trimetric monitor

(2) Group 31 AGM batteries

 

Today....46 degrees / Panel location ....41.6130° N, 70.9705° W  (50miles south of Boston, Massachusetts) Not a cloud in the sky. I just washed the panels. Sparkling clean!

The Trimetric is showing the panels delivering only 1.8A yet when I use my clamp on meter at the 4g wire feeding the Bogart 2030 charge controller, I'm showing 4.8A

When the sun  went down last night the Trimetric showed the batteries at 70%.....today at 11AM it is showing the batteries at 88%

Does all this sound like the system is working properly?

RoyB

South of Boston

2021 Dodge 2500 - 6.4L

Forest River 19RR Toy Hauler

Roofnest Falcon Rooftop Tent

www.rvbprecision.com

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2 hours ago, rbertalotto said:

Does all this sound like the system is working properly?

Nope. I would start by checking your shunt to ensure you have a solid connection but sounds like your trimetric microcontroller may need a reset. Start with the troubleshooting guide and go to the "amps not measured correctly" link then work your way down. Take note of which shunt you currently have installed.

As far as production goes... based on your current location you'll expect around a 15-20% reduction in solar production from the standard regional solar maps for this time of the year. Still seems a bit low for 3-140's, but that could be due to the orientation of your rig and your panels not hitting parallel to the sun arc. Just the nature of the beast

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Thanks, I also asked the same question of Bigart and they want me to use a different meter as they think my clamp on meter is inaccurate at these lower amps.

I'll look into that trouble shooting guide.

RoyB

South of Boston

2021 Dodge 2500 - 6.4L

Forest River 19RR Toy Hauler

Roofnest Falcon Rooftop Tent

www.rvbprecision.com

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35 minutes ago, rbertalotto said:

they think my clamp on meter is inaccurate at these lower amps.

I don't know about that. It certainly depends on your meter, but these days, even less expensive DC clamps have tolerances in the  +/- 5% range. My math might be a little rusty, but I have a suspision that 4.8amps over a 1.8 reading "might" be a little more than 5%. ;)

For 3-140's a 1.8a in and of itself glares of a trimetric microcontroller or shunt issue.

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So, at sun-up I was at 70% (not sure the voltage) and by 6PM I'm at 100%/13.5v....Wish I knew at what time it hit 100%

My trailer is a means to an end. We do not use it to actually sit in all day using electronics. We attend shooting , motorcycle and sport events where we are in it for breakfast and back sometime around 4PM for the evening. So my observation is that it works great! I've not used the generator except for the air conditioning a few times this summer and my wife's hair dryer. This system has been in place nearly three years now.

No matter the weather, by 4PM it is always back to 100%. This past weekend with three days of overcast skies was the greatest challenge it faced and the first time I ever saw the batteries below 75%.

Last February, in Phoenix, the batteries were at 100% by noon!  Love the high sun angle. The panels sit flat on the roof of the trailer which I am well aware is not optimum.

You can read about my entire install here:

http://rvbprecision.com/rv-projects/solar-install-grey-wolf-19rr-toy-hauler.html

RoyB

South of Boston

2021 Dodge 2500 - 6.4L

Forest River 19RR Toy Hauler

Roofnest Falcon Rooftop Tent

www.rvbprecision.com

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Other than the trimetric hiccup it sounds like you're in good shape. Looking at your install link the only suggestions I could think of would be to ensure all 3 panels are laying at the exact same angle. It might just be an optical illusion from the photo but it looks like the single is laying flat and the other 2 are pitched outward at a slight angle due to a curvature in the roof.(?) Not terribly critical with parallel arrays, but it may boost efficiency a bit. As is, you're likely getting just a tad of loss in "back flow/resistance" up the wire run from the lower producing panel at certain times of the day.

Then again, if it ain't broke... etc etc. 

You're energy requirements seem quite modest but maybe something to consider when you're due to retire your current battery bank might be to go with true deep cycle cells next go around. IIRC those duracells are 105ah/ea. So... 105ah available. You "could" have 220ah cells and double your available so you'll likely never drop much under 85-90% SOC and don't need to kick over your genny to handle a large load... like your better half being able to run her hair blower. 

Gotta love unlimited free energy! :P

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22 minutes ago, rbertalotto said:

He thinks I’ll losing something somewhere.

Very well could be. I looked a little further down your link and saw this photo. Maybe you could explain what's going on there on your shunt? Without knowing exactly it kind of looks like your controller output is on the wrong side of the shunt or your trimetric lead may be on the wrong side. (?)

 

P9050016-vi.jpg

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Red wires are "+" and black are "-"

The + is connected to the in and out plus on the 2030. The ground goes to the shunt and all loads are on the other side of the shunt. I don't think it matters what side is load and what side is "feed"....

RoyB

South of Boston

2021 Dodge 2500 - 6.4L

Forest River 19RR Toy Hauler

Roofnest Falcon Rooftop Tent

www.rvbprecision.com

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Just got off the phone with Bogart Engineering. He had me run a number of tests to determine if the 2030 charge controller and the TriMetric was operating properly. Everything checks out OK.

I then when up on the roof and disconnected the three panels and checked voltage

19.9v

20.0v

20.4v

The 19.9 panel has maybe 5% of the panel shaded by the AC unit. Just a little bit in the corner.

Comments?

 

RoyB

South of Boston

2021 Dodge 2500 - 6.4L

Forest River 19RR Toy Hauler

Roofnest Falcon Rooftop Tent

www.rvbprecision.com

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54 minutes ago, rbertalotto said:

Red wires are "+" and black are "-"

The + is connected to the in and out plus on the 2030. The ground goes to the shunt and all loads are on the other side of the shunt. I don't think it matters what side is load and what side is "feed"....

I kinda figured the red and black seeing how you can see the full cable runs from the controller in the picture... clearly labelled. Have no "absolute" idea what the other connections or yellow cable are, but no skin off my nose. :lol:

Re-reading your OP it may also be likely that you were reading 1.8a on the meter because that was all it was able to "push" on a nearly filled battery bank and the the 4.8a, as you said that reading was from the c-box to controller run, might have been the array's controller input... but not necessarily the actual output.

The clamp reading should have been made on the controller output line to make any meaningful comparison against the trimetric reading. I mistook it that that was what you had actually done. My bad.

As long as your meter sensor lines are the furthest "upstream" to your direct battery bank connection it should be fine.

You're individual panel readings probably aren't worth making any changes at this point.. but something to remember on future installs. As production increases, so will the differentials and potential efficieny losses. Granted.. it probably doesn't make much difference in your situation, in the grand scheme of things, since your energy requirements are so minimal.

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I disconnected the three panels on the roof….

 

Readings are:

20.3V….3.94A

20.0V.…4.01A

19.8V….4.57A

 

When connected back together

19.2V….Couldn’t measure amps as my meter only goes to 10A and it burn out a land on the circuit board. (I took it apart and soldered a bridge to fix it)

 

Interesting that the panel reading 4.57A was slightly better positioned to the sun as the camper has a round roof and that panel was facing sun more than the other two.

 

The spec on the panels I’m using is attached

P9020037vi-vi.jpg

 

Doesn't seem that these panels are putting out as advertised or is it simply because they are not oriented optimally to the sun?

RoyB

South of Boston

2021 Dodge 2500 - 6.4L

Forest River 19RR Toy Hauler

Roofnest Falcon Rooftop Tent

www.rvbprecision.com

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37 minutes ago, rbertalotto said:

Doesn't seem that these panels are putting out as advertised or is it simply because they are not oriented optimally to the sun?

That depends entirely on how you are  trying to measure current ouput... which can only be done with a load on.  Using a nearly full battery bank as your load won't cut it. The load has to be able to accept the full capacity of your array/s. Connecting directly to a panels outputs with a multimeter will only read the closed circuit amps.

And yes. Orientation to the sun is important.

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You mentioned shade from the air conditioner on 5% or less of one panel.  Any shade on a panel will kill the current output of the panel.  However I believe shade does not affect the voltage much at all.

The reason I asked earlier if the panels were wired in parallel, is if they were wired in series and you had shade on one small corner of one panel it would kill the output of all the panels wired in series. 

For a test sometime take something up on the roof and cover one solar cell on one panel and see what it does to your output.  You will see that you loose all most all the output from that panel. 

 

Al & Sharon
2006 Winnebago Journey 36G 
2020 Chevy Colorado Toad
San Antonio, TX

http://downtheroadaroundthebend.blogspot.com/

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Panel orientation to the sun is critical.  As far as the rated output, of 140 watts, that is only achieved under laboratory conditions.  In actual use to approach the 140 watts in the USA, you would need to be at the southern tip of Texas or Florida, on a perfectly clear day, no haze or dust in the sky and the panels perfectly perpendicular to the sun.  Also on or about June 22 for the summer solstice.

It is good that you wired your panels in parallel and used good heavy wire from the junction box to the controller.  If you installed all 3 panels in series and one of more of the panels is sloping away from the sun while the others are angled more toward the sun, the panel(s) tilted away from the sun will limit the total output. 

For an excellent video demonstration of this effect go to this video of a couple tilting their 6 panels toward the sun.  

The are getting about 36-38 amps as they are titling the panels.  As soon as the 6th panel it titled, the current jumps from 38 amps to 50 something amps. The last panel is tilted at about the 2:30 minutes of the video. 

Al & Sharon
2006 Winnebago Journey 36G 
2020 Chevy Colorado Toad
San Antonio, TX

http://downtheroadaroundthebend.blogspot.com/

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