Planning a Sol Ark 15k system for our ranch, after solar company went bust.

[Ampster]

This puts me over the Sol Arks rated operating voltage limit by a nose...

According to this spec sheet the max MPPT voltage is 500 volts. I do no know what the spec means by operating range but most days in your environment the higher temperatures will reduce the voltage. It is only the cold weather that could raise it. Depending on the conclusion about the operating voltage I would favor a higher voltage, especially if the distance from your arrays to the SolArk is a long distance. Higher voltage will allow smaller wire and have less voltage loss. I do not remember the constraints of your layout.

 

[Nobodybusiness]

OK home depot order arrived, had some stuff come up, had to do some traveling on business.. Haven't got the new box even un-packaged yet, but also computed around in my head a little bit, and had some thoughts, i know, scary, but hear me out.

Right now if i chain up the panels in 4 rows of 12, that gives me 4 rows, each operating at 432 volts @ 240 watts. This puts me over the Sol Arks rated operating voltage limit by a nose...

Would it be better to instead chain them together in 8 sets of 6 panels and then parallel 2 sets each, which if my math is working today would be 4 parallel sets at 216 volts @ 480 watts. and then paralleling 2 of those togeather going into the sol arks MPPTs, should give me 2 sets of 216 volts at 960 watts, and should leave the third MPPT open for future use later on, when i get some newer panels.

Use this.

Solar Panel Sizing 4.7

www.sol-ark.com

 

[JurassicRanch]

According to this spec sheet the max MPPT voltage is 500 volts. I do no know what the spec means by operating range but most days in your environment the higher temperatures will reduce the voltage. It is only the cold weather that could raise it. Depending on the conclusion about the operating voltage I would favor a higher voltage, especially if the distance from your arrays to the SolArk is a long distance. Higher voltage will allow smaller wire and have less voltage loss. I do not remember the constraints of your layout.

The array is 6-8 feet from where the Sol Ark will be mounted.

 

[JurassicRanch]

Use this.

Solar Panel Sizing 4.7

www.sol-ark.com

ITs not working unless im doing something wrong all it does is give me a stupid error message...

 

[Danke]

ITs not working unless im doing something wrong all it does is give me a stupid error message...
View attachment 217232

“ The values in part two cannot be null”. Change those to something other than zero.

 

[DIYrich]

26a is the max per mppt. At 4 strings, that is 32a. You will clip production.

6 strings of 7 panels into 2 of the mppt, and one string of 6 into the 3rd. When you are ready to expand, you can figure out what to do with the 6.

Upon further reflection, do 6 strings of 8 panels, and put 3 strings into each of 2 mppts (use a combiner).

 

[glandpuck]

The MPPT maximum of 500 volts provides flexibility for site design and installation. BUT, in terms of power production, you are not getting more power running at 250 volts vs 400 volts. That is what the MPPT controller does, it calculates the maximum power that the batteries can absorb in amps and then changes the RAW incoming volts and amps to a lower voltage and higher amperage to maximize battery charging. This does not apply directly to AC loads.

All battery types, including lithium have a charging curve. Think of it like this: You are filling up your soda cup at the self serve fountain. Initially you press hard on that fountain spigot to get that soda bubbling up full blast, but as you get closer to the top of the cup, you back off on the spigot pressure and try to make a smooth fill to the top without spilling (unless you still behave like a child). Same applies to charging batteries. But lithium batteries have a BMS onboard that does the thinking specific to that particular battery, while the thinking for a flooded lead acid battery and AGM battery ARE in the charge controller. The charge controller wants to know your battery type.

Remember, batteries, depending on type charge up to 62 volts for 48 volt systems. This means even with an MPPT input voltage of 250, your controller has plenty of "space" to maximize power.

So charging at 350 vs 450 is not better and may just produce more heat.

 

[Quattrohead]

The Solark 12/15k and EG4 18k do not blow up if the PV is over the recommend voltage, they just shut down the PV with an error code. You have 100v headroom on the 18k, not sure what it is on Solark.
I think on both of them the maximum efficiency is around 360 volts

 

[LydMekk]

Yeah 370V PV max efficiency for the Sol Arks.

 

[JurassicRanch]

I have four possible ways im considering connecting the panel strings togeather, I think C or D is probably the way to go, even though i will have to run a bit of extra cable more than first planned. Probably Plan C to be honest, but everyones thoughts are welcome, The 2 combiner boxes arrived so might go into mounting them and routing cables in my next bit of free time, would hope to only do it once and not have to redo it.

If there is a better layout i am missing out on, please feel free to sketch me one. Consider this a top down view of the panels that are on the awning.

For Reference, the Inverter and new Main Panel would be located 5 feet above the Top Left corner of the diagram. The new 40 slot main panel is here, as are all the breakers, unistrut, combiner boxes, still waiting on the unistrut bolts and hw kit to mount the panel to the strut.
View attachment 218522

View attachment 218523

View attachment 218524

View attachment 218525

 

[glandpuck]

I performed my own calculations and I matched up with your attachment 218525. I think this works best because it will be easy to make the connections and more importantly, easiest to troubleshoot and if necessary replace a panel in the future. Easy to work on individual strings and is in a nice sweet spot for voltage.

Additionally, if you upgrade to newer panels in the future, they will be easier to install wired this way.

 

[JurassicRanch]

still trucking, but ran into a snag, nobody local has 2 AWG cable for me to setup my new breaker box, hoping they get it back in stock sometime soon, but i may end up having to drive out to another town to get it, the nearest Home Depot is 60-90 minutes away, same with lowes, we have an Ace HW that is out of stock on tons of stuff and a wal-mart, thats about it.

I ordered in some 4 AWG Aluminum direct burial cable to run out to the well from the new box, but without the 2 to feed it no point in taking everything apart just yet. I cannot find a good deal to order the 2 without either buying a whole spool, or paying with an arm, a leg, and other much needed body parts. I stopped in the Lowes in Chandler when i was in the area on business, but all they had was about 12 feet of black 2 gauge, out of stock on the other colors, and not even enough black left to just use that and color code it with tape. Must be a run on copper wire atm...

 

[42OhmsPA]

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still trucking, but ran into a snag, nobody local has 2 AWG cable for me to setup my new breaker box, hoping they get it back in stock sometime soon, but i may end up having to drive out to another town to get it, the nearest Home Depot is 60-90 minutes away, same with lowes, we have an Ace HW that is out of stock on tons of stuff and a wal-mart, thats about it.

I ordered in some 4 AWG Aluminum direct burial cable to run out to the well from the new box, but without the 2 to feed it no point in taking everything apart just yet. I cannot find a good deal to order the 2 without either buying a whole spool, or paying with an arm, a leg, and other much needed body parts. I stopped in the Lowes in Chandler when i was in the area on business, but all they had was about 12 feet of black 2 gauge, out of stock on the other colors, and not even enough black left to just use that and color code it with tape. Must be a run on copper wire atm...

 

[JurassicRanch]

OK, another problem i ran into, is when ordering wire, i see it listed as 2/0-2/0-2/0 or #2, or just 2/2/2 but they look like different sizes, i recently installed a 3.5 ton A/C on my shop, and the instructions said recommended 6 gauge, 8 gauge acceptable, i forget how it noted it exactly, well, the 6 gauge i bought wont even fit into the screw downs, its too thick... I called their support line and they said something about the manual being written using a different unit format, and to just use 8, which fit but was tight. I think they might have said something about metric vs imperial or something. This was a MrCool 36,000 BTU single zone Mini Split A/C for reference.

I am sure i am missing something here, can someone please spell it out.

 

[Nobodybusiness]

OK, another problem i ran into, is when ordering wire, i see it listed as 2/0-2/0-2/0 or #2, or just 2/2/2 but they look like different sizes, i recently installed a 3.5 ton A/C on my shop, and the instructions said recommended 6 gauge, 8 gauge acceptable, i forget how it noted it exactly, well, the 6 gauge i bought wont even fit into the screw downs, its too thick... I called their support line and they said something about the manual being written using a different unit format, and to just use 8, which fit but was tight. I think they might have said something about metric vs imperial or something. This was a MrCool 36,000 BTU single zone Mini Split A/C for reference.

I am sure i am missing something here, can someone please spell it out.

2/0 AWG is definitely different than 2 AWG.

8 AWG should be fine for a 3.5 ton unit with no heat strips.
Should have a recommended breaker size on there somewhere which should give you an idea of gauge size.

 

[Birdog]

What kind of well pump is on the system? My 12k couldn't handle the amp surge of a jet pump.