Need some advise

Jim45D

I'm in the process of additional upgrades (watt wise & controller) to my solar system. Presently I have 4@ Kyocera 80 watters, three of which are tilted for my location. My upgrade will consist of an additional panel, A 140 watt Kyocera. My question is concerning splicing of the previous connections in order to eliminiate some excess wiring. I only use junction boxes. However, in the moving around of the panels I will need to eliminiate wiring, and re-position some of the panels. What is the best connector? I have looked at several from our host NAWS, but haven't decided as of yet. This is an RV installation. I always positon as to keep the panels due south, and I have always used a smidgit of silicone dialectric grease on the final connections to said junction boxes.

I will also be upgrading to the Rogue 30 amp MPPT charge controller to accomodate the extra wattage. According to my calculations that will give me approx. 460 watts, and with the degrading factor of 0.77, 354 watts, at my present location in Arizona. That being, 354/12=29.5 amps. The controller should handle that well. I hope. It will be charging 3@ T-1040 Concorde Sunextenders.

My present tilt is set at 43 degrees. My Lat. is 33 degrees. I leave them at this setting constantly. However, by this summer we plan to move to Ensenada, Mex. where the lat. is 31 degrees. I have come to a happy medium of tilt angle of 42 degrees. Am I in the ballpark? Secondly, where we will reside in Mexico is close to the ocean....some 300 yds. Will the haze, salt air, fog have a significant impact on my panels. I realize to a degree it will have, but I still hope to harvest somewhere in the neighborhood of 5.5 hours per day of production. Should I derate my panels more? I read somewhere that in some areas the derating could go to as low as 52.
Please advise, especially on the connectors. My wire run is #6 stranded, UV protected, and the longest length from my futherest panel is approx. 12 feet. to the controller. Controller to battery bank less than 5 ft. Shooting for the 500 mark, as revenue dictates, mabey more.

Thanks in advance. Jim

niel

Re: Need some advise

i won't say a preference to any connectors, but after you make the connection if you slipped heat shrink tubing over the wire you can make for a better protected connection.

you must be careful to not underrate a controller capacity for an application. never should you design to go right to the limits of a controller and that goes especially for the mppt types. now keep in mind the 77% derating is somewhat arbitrary for most typical applications, but you can at times see the full output of the pv. there may be days of higher insolation and even edge of cloud events that could bump it up. also keep in mind that an mppt controller is designed to help bump up the current and that these controllers are limited in their output currents creating a circumstance that you could be losing potential output by undersizing your controller. always assume for the sake of controller choices that your pvs could output their full power and dividing that by the lowest battery voltage you'd expect to see could reveal quite a bit of current potential. either go with more than one controller or opt for a bigger one. the 52% is total average system efficiency and not just pvs.

it is hard to say what may work out the best for your solar angle and i will assume you can adjust yours so maybe adjusting for various seasons is best rather than just one angle year round. most opt for about latitude +15 degrees for a year round angle, but local conditions can make general recommendations obsolete. even pv watts and other such calculators can miss the mark if different from the actual place they calculated for.

Diver

Re: Need some advise

niel,

I think the year round angle would be latitude and the winter angle would be latitude +15 (summer, -15).

niel

Re: Need some advise

Diver wrote: »

niel,

I think the year round angle would be latitude and the winter angle would be latitude +15 (summer, -15).

not so because at latitude is the highest average height the sun gets in the sky at solar noon with 0 degrees at the equator being flat to the ground. most times the sun is lower to the horizon and therefore the extra 15 degrees accounts for this meaning you can't just design for the average solar noon. i also believe you may be thinking of seasonal wobble and that is +/- 23.27 degrees and not +/-15 degrees.

Jim45D

Re: Need some advise

Yes, my panels are adjustable. I have read several articles concerning tilt. Some say +/- 10° depending on the winter/summer soltice. Another say's it's possible to obtain 4% more production if the tilt is set at Lat. +/- 15° plus an additional few degrees up to 7° +/- 4 times per year. The 15° setting +/- is the setting most recommended. The only reason mine were at 10° above Lat. is because it's a chore to climb up and down the ladder several times for adjustments, and they were set at 10° (holes drilled in the adjusting arms) prior to installation. I left them at that. However, during my re-vamp shortly imminent, they will be re-drilled, and set at 15°. I simply cannot be degreeing myself to death. I think twice per year is sufficient. At least for me it is.

mike95490

Re: Need some advise

I leave mine set for the Nov/Jan angle (forgot what it was) because in those months, I need every bit of sun, and summer, with longer days, I don't need max output (till I put in air conditioning)

niel

Re: Need some advise

mike90045 wrote: »

I leave mine set for the Nov/Jan angle (forgot what it was) because in those months, I need every bit of sun, and summer, with longer days, I don't need max output (till I put in air conditioning)

mike,
lately i've come to think about it like you do. the longer summer days tend to still keep a high production overall even though not at optimum. i didn't readjust the winter angle for a summer angle last year. let's face it that it is not at optimum anyway because of the long track the sun takes during the summer unless one uses a tracker, which i don't deem worth the extra costs. i do hold the winter angle to be necessary during the winter as the lesser times it is in the sky and lower intensity make it so so i angled for a bit more than lat +15 degrees to optimize that winter production and keep snow off. i believe mine is a tad over 60 degrees tilt. (snow i assume is not one of your problems mike?) the full angle for winter solstice is lat +23.27 degrees. adjusting for that angle is perfect at solar noon on the winter solstice, but at other times of the day the sun is closer to the horizon meaning an even larger angle to take better advantage of the sun during that time of year. in nov and jan the solar noon angle is higher over the horizon than the angle it's at for solar noon on the solstice and takes advantage of the lower sun angles at other times of the day during those months.

when you use the a/c you may still want to readjust the angle more for summer production for the sun is somewhat close to going from east to west straight over head during the summer the closer one is to the tropic of cancer line that you are. i'm further north so the sun, even in the summer, does arc out further and is not as much over head. the setting we are currently using mike is a good compromise when opting for a fixed setting favoring winter production and is kind of an opposite thinking that those with gt use as this optimizes production when there's the least capability. gt systems optimize for year round overall production. i'll shut up now as everybody is probably very confused right now.

Diver

Re: Need some advise

From Wholesale Solar:

Solar panels produce the most electricity when they are facing as close to perpendicular as possible. As the sun travels at varying angles throughout the year, you need to adjust the angle to the sun at least four times a year. The closer to perpendicular they are, the more output you will get. We recommend that you change the angle on your solar panels on these dates:

◦February 5th - Set to same angle as your latitude.
◦May 5th - Set at the same angle as your latitude minus 15 degrees. At noon the panel will be almost horizontal to the ground.
◦August 5th - Set at the same angle as your latitude.
◦November 5th - Set at the angle of latitude plus 15 degrees. This tilts your panels towards the sun as it travels low in the southern sky during the winter.

niel

Re: Need some advise

diver,
there's nothing wrong with doing it as you list from wholesale solar's advice. what i listed was a compromise angle that i opted to have and not move from it. if one were to get technical about it you could readjust the angle more often than even they recommend and have a tracker as well. you must understand that there's isn't any one answer to aiming and even though for most instances what you have written is fine for most people, but there are exceptions due to weather and large bodies of water nearby are 2 possibilities. my higher angle also affords better collection due to snow reflections than the lat +15 degrees would do. i guess during the summer i should get my butt out there and optimize it for that at least and mike would also benefit from doing at least 2 adjustments as well, but my point was that as a compromise goes what mike and i have utilized isn't as bad as you might think.