sunny boy inverter?

[Ampster]

Go to solarpaneltilt.com for a thorough treatment of solar PV panel tilt angles....

Interesting article that includes TOU pricing to suggest that a slight westward orientation would optimize revenue in some cases. Your mileage may vary.

[mudhole]

ya, my roof is at 210 degrees (azmuth), which should help with our late afternoon summer rates.

[J.P.M.]

Go to solarpaneltilt.com for a thorough treatment of solar PV panel tilt angles....

FWIW, that's not a bad treatment of what are possibly good 1st approximations of fairly optimal tilt angles vs. season. Although I'd take issue with a few of the author's points such as always having an array azimuth that reads like it's supposed to be inflexibly normal to the equator, the suggestions given will probably keep most folks out of trouble.

[mudhole]

well the solar panels and the inverter have arrived, sunny boy 5.0 -41, and 18 talesun panels tp660p-275, still waiting on the rails

i plan on laying the panels out in 6x3 rows, running 2 strings into the inverter on separate mppt inputs, , the open voltage is 38.7 and the operating is 31.7, when i checked the panel it was around 37 volts, this was late in the day and i just stood them up, almost upright . this would give me about 330 volt string(well within the input range of the inverter), from videos i have seen, cable management was basically plug them in series and just let them hang under the panel, is that the correct , NEC, way of doing it?

[J.P.M.]

Mudhole:

Maybe this is a bit like closing the barn door after the horse got out, but did considering the electrical load you have and how much of that load you want to offset w/PV get any considertion in your planning/design ? I haven't seen any mention about how you came up with an array size.

[Ampster]

...............
from videos i have seen, cable management was basically plug them in series and just let them hang under the panel, is that the correct , NEC, way of doing it?

Most people clip the the cables to the rails instead of leaving them hanging. If you use zip ties use ones that will not degrade over time. I don't know what NEC says, but common sense is that you don't want them to chafe in in the wind cause a short or current leak.

[mudhole]

jpm-the thought that went into the array size was given a little thought our bill is never more than $150 a month, and that is in the hot part of the summer, i heat from a wood stove with just a back up heat pump that rarely kicks on. so i figured around 1500 kw-hr a month, this should offset about 2/3rds of that in the summer if i get at least 7 hours of sun (very modest estimate), the main thought was to have something that if we lost grid power for a long time, i would have back up to run a freezer, the sunny boy affords that without batteries (as long as the sun shines), up to 2kw.

ampster- attaching to the rail is definitely the way to go, thanks

[J.P.M.]

jpm-the thought that went into the array size was given a little thought our bill is never more than $150 a month, and that is in the hot part of the summer, i heat from a wood stove with just a back up heat pump that rarely kicks on. so i figured around 1500 kw-hr a month, this should offset about 2/3rds of that in the summer if i get at least 7 hours of sun (very modest estimate), the main thought was to have something that if we lost grid power for a long time, i would have back up to run a freezer, the sunny boy affords that without batteries (as long as the sun shines), up to 2kw.

ampster- attaching to the rail is definitely the way to go, thanks

Thank you.

[mudhole]

help with the nuts and bolts of the system

1. i am running 2, 9 panel systems , roughly 300 volts each, into separate mppt inputs on the inverter, I know i need an AC disconnect, should it be fused/breaker? ,

2. i think i should also put in a DC disconnect before the inverter so if i ever have to do work at it, i can open the circuit, I am assuming this is typical?

3. what is the easiest way to bond the rails/panels?

thanks in advance for any and all help

[Ampster]

help with the nuts and bolts of the system

1. i am running 2, 9 panel systems , roughly 300 volts each, into separate mppt inputs on the inverter, I know i need an AC disconnect, should it be fused/breaker?

2. i think i should also put in a DC disconnect before the inverter so if i ever have to do work at it, i can open the circuit, I am assuming this is typical?

3. what is the easiest way to bond the rails/panels?
..........

1. The AC disconnect has to be on the outside and have air gap. You will also need a breaker at the panel where that circuit attaches to the bussbar. It would be redundant and expensive to fuse the external disconnect.
2. My inverter has a DC disconnect. If yours has one you don't need another one unless required.
3. The easiest way is to buy the clips that are engineered to do the bonding of the panel to the rail. Then you only need to bond each rail to the ground.

[mudhole]

1. The AC disconnect has to be on the outside and have air gap. You will also need a breaker at the panel where that circuit attaches to the bussbar. It would be redundant and expensive to fuse the external disconnect.
2. My inverter has a DC disconnect. If yours has one you don't need another one unless required.
3. The easiest way is to buy the clips that are engineered to do the bonding of the panel to the rail. Then you only need to bond each rail to the ground.

gotcha on 1 and 2, on 3 however, if the rail is coupled, i probably have to bond that?

also , are there special connectors to use for the ends of the panels?, for when i am done connecting them in series, i will have a positive and a negative lead , are there specific connectors that plug in to the panel lead and then are just wire to the inverter for the dc in?


sorry for all these rookie questions, i have not been able to find a video that addresses these things

[Ampster]

gotcha on 1 and 2, on 3 however, if the rail is coupled, i probably have to bond that?

Yes, that is what I meant by, "bond each rail to ground." Did that answer your question?

also , are there special connectors to use for the ends of the panels?, for when i am done connecting them in series, i will have a positive and a negative lead , are there specific connectors that plug in to the panel lead and then are just wire to the inverter for the dc in?

I usually buy an extension cable of the correct length and cut it at the appropriate spot. Then you have two cables one with a connector for the positive and one for the negative. the cut ends each go through a cable gland into the junction box. Note, the wire length of these will be different depending on how you connect the panels and if you have a single row of panels (or an odd number of rows). If you start at one end and daisy chain then you will have one short and one long part of the extension cable if your jbox is at one end. There is a process if your panel cables are long enough where you alternate panels going down to the end and pick up the unconnected panels on the way back. I wish I had a picture which someone on another thread posted. That method saves wire.

sorry for all these rookie questions, i have not been able to find a video that addresses these things

No worries, that is how these threads become a valuable resource for others. I learned that cable saving trick just a few months ago on this forum after I had wired my single row of panels on my patio cover.

[mudhole]

Yes, that is what I meant by, "bond each rail to ground." Did that answer your question?

I usually buy an extension cable of the correct length and cut it at the appropriate spot. Then you have two cables one with a connector for the positive and one for the negative. the cut ends each go through a cable gland into the junction box. Note, the wire length of these will be different depending on how you connect the panels and if you have a single row of panels (or an odd number of rows). If you start at one end and daisy chain then you will have one short and one long part of the extension cable if your jbox is at one end. There is a process if your panel cables are long enough where you alternate panels going down to the end and pick up the unconnected panels on the way back. I wish I had a picture which someone on another thread posted. That method saves wire.

No worries, that is how these threads become a valuable resource for others. I learned that cable saving trick just a few months ago on this forum after I had wired my single row of panels on my patio cover.

ahhh, i think i understand what you are saying with skipping, that way both leads are next to each other (connect 1,3,5,7,9 in one directions, 8,6,4,2 coming back. i will need to order 2 extensions since i am running them into separate mppt inputs.

[mudhole]

i watched the iron ridge bonding/grounding video, i get it now, the panels are bonded to the rail via the end and mid clamps, i dont actually have to screw a lug into the panel and run the wire through it,. i just need to bond the rail via lug and any splices and run them to earth ground via 6 awg bare copper.

as far as code goes, can i use pvc conduit for both the dc and ac lines?

[Ampster]

i watched the iron ridge bonding/grounding video, i get it now, the panels are bonded to the rail via the end and mid clamps, i dont actually have to screw a lug into the panel and run the wire through it,. i just need to bond the rail via lug and any splices and run them to earth ground via 6 awg bare copper.

as far as code goes, can i use pvc conduit for both the dc and ac lines?

Check the Iron Ridge splices, they may do the bonding with the way the screws self tap. At least that was my assumption on my last self install from what I read about my particular rail. On an earlier UniRac system I self installed bonding straps were required.
Double check the code and labeling requirements but I am pretty sure the AC and DC have to be in separate conduits. Every jurisdiction has its own interpretation. In one jurisdiction where I had solar installed and did a self install, the DC had to be in EMT or Rigid and could not even be in flexible conduit. I think DC has to be labeled differently because of potential for much higher voltages.