Considering DIY Long distance from panels

[rhino]

40-50kWh was probably dreaming on my part. Can the strings all run together to the triplex and then be branched off near the inverter to the number of input points of the inverter?

No. Each charge controller input must be connected to its own set of panels so that it can figure out what the optimum maximum power point tracking is for those specific panels. You are then back to being limited by the maximum amperage a single MPPT tracker can accept.

Is the standard to have multiple smaller charge controllers vs on large one?

Many high voltage charge controllers and all in ones have multiple "trackers" so they can accept 3 and sometimes 4 separate strings (a string being a positive and negative cable for those specific panels in that string).

 

[georgia088]

No. Each charge controller input must be connected to its own set of panels so that it can figure out what the optimum maximum power point tracking is for those specific panels. You are then back to being limited by the maximum amperage a single MPPT tracker can accept.


Many high voltage charge controllers and all in ones have multiple "trackers" so they can accept 3 and sometimes 4 separate strings (a string being a positive and negative cable for those specific panels in that string).

So by connecting them all together with the one cable I would basically only have 1 "set" of panels and one "tracker" meaning I would be limiting all of the panels to the lowest power point of all the sets of panels?

 

[Zwy]

40-50kWh was probably dreaming on my part. Can the strings all run together to the triplex and then be branched off near the inverter to the number of input points of the inverter?

Anything is doable but takes $$$$'s.

I'd use the triplex for another purpose, it isn't ideal for what you want to accomplish.

Is the standard to have multiple smaller charge controllers vs on large one?

I run a pair of MPPT's for my array. These are rated for up to 500V VOC. My pair of inverters are rated for 250V VOC and with my array 420 feet one way distance I wanted the higher PV voltage. Higher PV voltage is less voltage drop, less power loss due to current. Keep PV voltage high and amps low will allow greater efficiency.

I always figure 4 to 5 hours for sun, anything in early morning and evening is just a bonus. You will need minimum of at least 15Kw for an array. Battery bank of probably double to triple your current daily Kwh. 100Kwh to 150Kwh would allow you to make it thru days of no PV production. If you plan on grid backup or generator, you might be able to go in stages until you acquire enough battery.

Now that you know that, do you have any idea what the max load is in your house at any time if several items were to start/run? This determines inverting power.

This won't be cheap by any means. Do you have a budget?

 

[Checkthisout]

40-50kWh was probably dreaming on my part. Can the strings all run together to the triplex and then be branched off near the inverter to the number of input points of the inverter?

As long as it's originating as separate wires at the array.

 

[georgia088]

You will need minimum of at least 15Kw for an array

Wow. That is a minimum for the panels? Do I understand you have 16 530W panels? Isn't that 8480W for your array? I'm confused

 

[Lt.Dan]

Wow. That is a minimum for the panels? Do I understand you have 16 530W panels? Isn't that 8480W for your array? I'm confused

I'll say this, I'm in a very sunny area, and yesterday my 11kW array only brought in 40kWh. So if you are looking for 50-60, you're going to need quite a bit.

I always just try to fill out any space I have with PV, more often than not, you run out of space. For the people who have acres and acres to put up panels, I am envious lol.

 

[Zwy]

I need 5500ah for my 11kw system???? I better get to work!!!

48V battery? That is some serious Kwh.

Wow. That is a minimum for the panels? Do I understand you have 16 530W panels? Isn't that 8480W for your array? I'm confused

40 to 50Kwh usage with 5 hours of sun, you will want 15Kw of panels, 10Kw will be somewhat short. You get days with limited sun/cloudy days. Read this thread I started the other day. https://diysolarforum.com/threads/get-a-big-battery.70751/ to understand there are times you will need to run loads but also provide enough power to charge batteries.

I have 8480W for an array. House total Kwh is usually 20Kwh and under. It will increase with colder weather probably another 10Kwh. I'm actually pulling in full sun with clear skies/colder weather full array capacity because I'm running high array voltage.

Is there any possible conservation you can employ? Upgrades on refrigerator, freezers, HVAC? Conservation pays because you won't need a larger system.

 

[georgia088]

48V battery? That is some serious Kwh.

40 to 50Kwh usage with 5 hours of sun, you will want 15Kw of panels, 10Kw will be somewhat short. You get days with limited sun/cloudy days. Read this thread I started the other day. https://diysolarforum.com/threads/get-a-big-battery.70751/ to understand there are times you will need to run loads but also provide enough power to charge batteries.

I have 8480W for an array. House total Kwh is usually 20Kwh and under. It will increase with colder weather probably another 10Kwh. I'm actually pulling in full sun with clear skies/colder weather full array capacity because I'm running high array voltage.

Is there any possible conservation you can employ? Upgrades on refrigerator, freezers, HVAC? Conservation pays because you won't need a larger sys

Ok, I think I misunderstood. You are saying a minimum of 15Kw of panels to completely rely on my system and not the grid at all. I thought you meant a minimum just to get started. I am really wanting to get my feet wet first before trying to completely run my whole house. What can I expect to start with if I use 1 48v (5Kwh) pack? How many panels? What size inverter? Easiest best way to connect to grid tie?

Thanks!

 

[Hedges]

Honestly, I don't know. I am open for suggestions.

Is the standard to have multiple smaller charge controllers vs on large one?

Multiple charge controllers, or multiple MPPT in one charge controller/AIO. Also multiple strings to one MPPT input. A few allow paralleling multiple MPPT for a single home-run wire. Maybe some will allow negative combined, two separate positive, better fitting your existing cable run?

"Power audit", as others recommend.

120V, or 120/240V?
Review appliances and plans, determine kWh/day summer, winter, other times.
Inverter no-load draw will be a significant part, unless only turned on for laundry, etc.
Determine peak kW running, peak kW to start motors.

Decide if you want to run all that off batteries for multiple days without sun, or if you can heavily conserve those time.


Consider a battery that would carry you for those days. (PV may contribute 1% to 10% of normal during heavy or light overcast.)
Determine how much PV is required, based on insolation calculators.

Look into inverters (and charge controllers if not included) able to deliver starting surge and running watts. Tabulate cost, no-load consumption, PV input quantity, voltage, current.

Growatt, EG4, Victron, Schneider, Outback, Midnight, SMA, others. Hardware could range from $400 to $20k, depending on many factors.

Divide PV wattage by (about 2/3 of) allowed PV input voltage of equipment. (Vmp when operating will be around 2/3 of max Voc.) This will tell you how many amps through the wire and into MPPT.

If you did an AC coupled system like my Sunny Island & Sunny Boy, you could have 7.7kW or 10kW going to a single 600V MPPT or paralleled MPPT (in some cases getting older models.) Victron has a 450V max 250A SCC, not sure how many MPPT. Schneider has a 600V SCC.

So you can have quite a few watts of array with up to 600V PV. At lower voltages like 250V, 150V, 100V there will be cheaper choices, less wattage.

You should make your array with strings pointed different orientations, SE and SW. This will allow 40% more watts of panels for a given peak wattage and current.

In the end you'll have many choices and prices to deliver quite a few kW, likely supporting your 50 kWh/day during summer.

 

[Zwy]

Ok, I think I misunderstood. You are saying a minimum of 15Kw of panels to completely rely on my system and not the grid at all. I thought you meant a minimum just to get started. I am really wanting to get my feet wet first before trying to completely run my whole house. What can I expect to start with if I use 1 48v pack? How many panels? What size inverter? Easiest best way to connect to grid tie?

Thanks!

"If I were to try to go off grid"- quote from first post

Load reduction is what you are looking for now? How many Ah is the 48V battery? 100Ah is about 5Kwh. 280Ah is about 13.5Kwh. Capacity is about 90% use able if you fully cycle the battery.

Grid tie can have the advantage of not requiring a battery. You could use the triplex. You need to determine if your utility allows it and under what terms. If it is 1 to 1 net metering, then it may make sense for your situation. If it is utility pays you a few cents and charges you 40 cents for that Kwh back then it probably isn't a good idea.

You could run a small system for load reduction that powers critical items such as fridge. Move those circuits to a separate loads panel and use grid backup. This can provide power to those items when the grid is down. You would size the critical loads system according to what you want to run, how many watts the items use and for how long you would like to run the items in a grid down situation.

 

[georgia088]

"If I were to try to go off grid"- quote from first post

Load reduction is what you are looking for now? How many Ah is the 48V battery? 100Ah is about 5Kwh. 280Ah is about 13.5Kwh. Capacity is about 90% use able if you fully cycle the battery.

Grid tie can have the advantage of not requiring a battery. You could use the triplex. You need to determine if your utility allows it and under what terms. If it is 1 to 1 net metering, then it may make sense for your situation. If it is utility pays you a few cents and charges you 40 cents for that Kwh back then it probably isn't a good idea.

You could run a small system for load reduction that powers critical items such as fridge. Move those circuits to a separate loads panel and use grid backup. This can provide power to those items when the grid is down. You would size the critical loads system according to what you want to run, how many watts the items use and for how long you would like to run the items in a grid down situation.

I know it is hard to find in this thread, but I have answered some of your questions.

I use 1 48v (5Kwh) pack

As for "If I were to try to go off grid" I guess that was not the best way to explain what I am attempting. I mean at some point maybe but not right off the bat. I apologize for the confusion.

I live in area where (as far as I can tell) does not offer net metering services.

 

[CoolWill]

Unfortunately this still means you will be stuck with a single string since you need a PV positive and PV negative plus a single ground wire coming back for the entire array. A single string will not be enough for the 40kWh to 50kWh you said you use daily. If you are wanting to offset that much you are going to have to run more wiring out there.

Putting the batteries and inverter out there may be the most economical route. There's less than 5% voltage drop at 100 amps on 4/0 over that distance.

 

[pvgirl]

Putting the batteries and inverter out there may be the most economical route. There's less than 5% voltage drop at 100 amps on 4/0 over that distance.

This will limit the system to off grid only, without any way to feed a grid hybrid or backup connection to the inverter.

 

[hwy17]

The triplex/quadplex is adequate to put the inverter at the far end, which would afford more PV design flexibility.

BUT, then you don't have the wire to run a hybrid inverter with utility input, you can't send the utility input out there and the output back.

Otherwise you combine say 15kw of PV onto the triplex and it comes back to a 48v 100A charge controller, and you're limited to 4.8kW of production but you're so over paneled that you get that 4.8kW pretty reliably every sunny day.

Unfortunately pvwatts will only simulate a max of 2.0 DC to AC ratio.

The 18kPV has a supposedly 25A 500V MPPT input and 250A charging current limit so looks like it can exceed 4800 watts on a single MPPT input. But I wonder if there isn't some kind of interdependent limitation that would keep it from reaching 10,000 on that input.

 

[Hedges]

As for "If I were to try to go off grid" I guess that was not the best way to explain what I am attempting. I mean at some point maybe but not right off the bat. I apologize for the confusion.

See if net metering is available. See if backfeed is allowed, even without crediting you, but at least without charging you (meter could count up regardless of power flow direction.)

I put in GT PV with Sunny Boys 20 years ago.
3 years ago I added Sunny Island for grid backup.
If battery large enough for nights and cloudy days, or if I added generator backup, I could run off grid.

GT PV inverter(s) could be at the array (AC through your 4/0), or at the house (HV DC through 4/0, only one MPPT input supported.)

There are "batteries optional" AIO/Hybrid available. SMA (coming January), SolArk, Growatt, EG4, others. They generally support net metering and zero-backfeed.

 

[CoolWill]

This will limit the system to off grid only, without any way to feed a grid hybrid or backup connection to the inverter.

That's true. I don't think about any grid tie stuff. Never caught my eye.

 

[Hedges]

This will limit the system to off grid only, without any way to feed a grid hybrid or backup connection to the inverter.

That's true. I don't think about any grid tie stuff. Never caught my eye.

Unless you put GT PV (e.g. Sunny Boy, Fronius, Enphase) at the array.
Which can then be optionally AC coupled to battery inverter back at the house.
This supports grid-tie, grid-backup, off-grid.

Benefit for OP's situation is he can have many MPPT for many PV strings, all combined as one 240V home run over 4/0 aluminum.
Battery inverter remains at house, no impact on motor starting surge.
Downside for OP, besides power loss at 240VAC rather than ~ 400VDC, is that high line voltage would be exacerbated by further voltage rise over the 500' run. If it exceeds 250Vrms, inverter disconnects.

However, the trend is toward HF, often with HV battery, AIO. e.g. SMA is replacing Sunny Boy GT PV with Sunny Boy Smart Energy hybrid (similar to SolArk and others, except it is 240V only not 120/240V split-phase without an add-on.) That puts battery at same location as where PV enters inverter.

 

[Zwy]

I know it is hard to find in this thread, but I have answered some of your questions.

As for "If I were to try to go off grid" I guess that was not the best way to explain what I am attempting. I mean at some point maybe but not right off the bat. I apologize for the confusion.

I went back thru and the only item I see for your residence is an air conditioning unit. The other was your parent's property in FL with a camper.

First, as I mentioned before, conservation pays. Replacing the current inefficient air conditioning unit with an inverter type heat pump will reduce the instant LRA load and the running load. It doesn't matter if you still use grid power, a newer unit will reduce your load per day and if you do decide to add solar it makes your system smaller and less costly. Currently there is a 30% tax credit on qualified heat pumps so it's really a no brainer to replace your current unit with something more efficient.

Newer fridges take very little power, our current fridge is about 3 years old and it uses only 1 Kwh per day. Get a Wattmeter and check each appliance you have for how much power it consumes in a day.

As for the camper, it would depend on how often they will run the air conditioning. RV air conditioning is very inefficient, very thirsty for watts. Will the units run all day? What is the current load?

 

[400bird]

This will limit the system to off grid only, without any way to feed a grid hybrid or backup connection to the inverter.

Standard grid tie is also an option, if the power company does not metering. I don't think it's a good option, just saying that is is an option.

For the OP, standard grid tie set up just pump out solar and any excess past what your loads are using at the moment are dumped onto the grid. Also, solar stops when power goes down, no back up power. No point in a battery with this set up either. Unless you add a second battery inverter at the house.

Depending on how much solar (in kW) your looking at, I'm still voting for one large array out at the field and inverter/battery at the house.

 

[pvgirl]

Unless you put GT PV (e.g. Sunny Boy, Fronius, Enphase) at the array.
Which can then be optionally AC coupled to battery inverter back at the house.
This supports grid-tie, grid-backup, off-grid.

I wonder if the for the costs of separate inverters for pv and battery it would be cheaper to just run new wire for PV DC circuits.