Sloped ground mount

[DC1]

A DIY guy with some questions. Planning an 8.3 k system, ground mount on about a 15 degree slope. The racking systems I've looked at say the max vertical pole height in the front can be only 30". with the slop my height will be about 48". Does any body have suggestions to solve this or just get an engineer and have them redo the specs. Also have a run of about 140' from array to meter. Do I put the invertor at the array and run AC to the house or invertor at the house an run DC.
Thanks
Dale

[Logan5]

is roof mount impossible? Shading?

[J.P.M.]

A DIY guy with some questions. Planning an 8.3 k system, ground mount on about a 15 degree slope. The racking systems I've looked at say the max vertical pole height in the front can be only 30". with the slop my height will be about 48". Does any body have suggestions to solve this or just get an engineer and have them redo the specs. Also have a run of about 140' from array to meter. Do I put the invertor at the array and run AC to the house or invertor at the house an run DC.
Thanks
Dale

If I understand the height dilemma correctly from what you're writing, lower the whole array design by 48" - 30" = 18".

[DC1]

Can't go on roof, too many trees.
J. P. M.- The left front panel will be 1ft off the ground and the right front panel will end up about5ft above grade, way to high for the racking system. To lower the system on the left side I would have to level the area for the install. That leads to more permits and building retaining walls. would rather not go there.

[ButchDeal]

Can't go on roof, too many trees.
J. P. M.- The left front panel will be 1ft off the ground and the right front panel will end up about5ft above grade, way to high for the racking system. To lower the system on the left side I would have to level the area for the install. That leads to more permits and building retaining walls. would rather not go there.

ok so it is an east/west slope. I along with JPM thought you were talking about a north/south slope.

You have other options, one is to step it down as you go along.
The other is to turn it a bit off from south to try to limit the slope issue.
third is a combination of the two.

so you would have say two south west facing arrays, one a bit higher than the other.
Also take advantage of the new racking, you didn't mention brands but ironridge supports 5 modules high on their rack which would limit the east west length.

[Eleceng1979]

Use ironridge ground racking system or rent a buldozer. The trivial cost of renting a dozer will surely be cheaper than the lifetime hit of going off angle or compromised foundations. I can rent a dozer for a weekend for $300 that will move plenty of dirt. Pretty fun too!

Placed at proper depth, diameters and spacing of holes the vertical above grade shouldn't be an issue provided calculations are done. Ironridge can be raised higher than 30" on the south poles but needs calculations done.

Ironridge quote...
The maximum “above ground length” for the southern vertical piers is 2’'6"”. To prevent exceeding this length on either side of the array, break the array into segments. This “stepped” array will prevent the East or West side of the array from being too high. If this is not a viable option, consult an engineer for alternative approaches

Pushing a marginal rack system to the limits isn't wise. Turning xxx degrees to meet the max height above grade seems counter intuitive, adds a different dimension of sloped earth under a sloped array for engineering calculations and will have soil creep issues if the slope is not stable and hole depth isn't right. You choose a rack system to suit the terrain...not the other way arround. There is margin in the design but I would choose a different system.

Keep in mind all generic calculations on hole diameter and depth are based upon level ground...

[foo1bar]

That leads to more permits and building retaining walls. would rather not go there.

If it's just a change of ~18" at each end (18" up at one end 18" down at the other) I wouldn't expect a retaining wall to be necessary.

But I'd probably be tempted to see if I could just pour a little more concrete and not bother with much earthmoving.
A stepped array probably is the better option though.

[DC1]

Thanks for the advice guys. Ran into more things to think about; my lot has a 20 ft lb snow load which will not let me go 4 high with Iron Ridge or Prosolar racking systems. Thinking the best way to go is 4 arrays 3 high with a little digging to get it within specs. Any other ground racking besides I. R. and P. S. ?
Also, run DC for 140ft or AC. Any large voltage loss either way?
Again thanks

[Logan5]

You will run AC the 140'

[foo1bar]

Also, run DC for 140ft or AC. Any large voltage loss either way?

Power loss will be proportional to current - which is inverse of voltage.
So you want to run the higher voltage one the longer distance.
But other considerations will probably take precedence.
Like "Where can I put the inverter so it's always in the shade?"
And "What do I need for a shutoff located at the array?"
And probably other questions that I don't know.

[Mike90250]

Auger a proper hole, and extend the concrete with a sonotube post ?

[DanS26]

Make the home run the higher voltage DC. Smaller diameter wires and less wires (three vs four). Plus a string inverter at the meter will be less costly than micros.

For a long run the savings in wire costs alone may pay for your inverter.

[Eleceng1979]

Im in central ohio with 48 panels, 4 high, 12 wide with 20lb/sq ft snow load and 100mph design in good soil, using ironridge ground mount and 3" piping. Your comment about this seems strange. I did the numbers myself on their online tool to verify the contractor for my installation, plenty of margin.

My array has over 450' distance from point to point DC string wiring x 4 strings to inverters and has less than 1.5% voltage drop. Run the higher dc long distances. These losses are easy to figure out and online tools exist as well.

[DC1]

Eleceng 1979 , if you are on a level east to west slope yes that works but if you have a 15 degree slope as in my case you end up with 30" at the west end but 40" over there limit of 30" on the east end. thanks for the input on the home run.

[Eleceng1979]

You can raise it over 30" but it requires engineering. Call iron ridge yourself. They show a generic drawing from their generic design tool due to this generic design getting certified by a professional engineer and was stamped for use in every state. They state the 30" max as this was there generic design considerations. All you need is a PE stamp on a new drawing showing it higher with adequate fondations and engineering. I would guess this should cost less than $1000 for this design work to happen.

Or rent a dozer...

You are seeking generic installation heights, pre approved for 90% of the installations in america. You are not in that generic group and require specific engineering due to your sloped install... square peg in round hole. Using any brand mount, with generic pre-approved pe stamped designs will not apply to you and will void warranties and cause you legal issues if something happens as you didn't install it on level ground per the approved design.

Or rent a dozer...