Best arrangement for what I have?

[cdunham]

Hi all, new to this....

I have a ton of 260 watts; 30.7V solar panels.... 35 to be exact.... I know I would not need to use them on for this.
I have a EPEVER 60A MPPT Charge Controller 48V 36V 24V 12V Auto, 60 amp Solar Controller MPPT Negative Ground Max 150V

I have 18 nissan leaf battery packs on the way... the specs are:
MODULE SPECIFICATIONS Number of cells 4 Construction 2 in-series, 2 in parallel Length 11.9291" (303 mm) Width 8.7795" (223 mm) Height 1.3779" (35 mm) Weight 8.3775 lbs (3.8 kgs) Output terminal M6 nut Voltage sensing terminal M4 nut Module fixing hole diameter 0.3582" (9.1 mm) CELL SPECIFICATIONS Cell Type Laminate type Cathode material LiMn2O4 with LiNiO2 Anode material Graphite Rated capacity (0.3C)/td> 33.1 Ah Average voltage 3.8V Length 11.417" (290 mm) Width 8.504" (216 mm) Thickness 0.2795" (7.1mm) Weight 1.7624 lbs (799 g)

I wasn't sure if I should put them in 24v or 48v. I know 48v allows me to have more power, but the 30.7V panels are throwing me off.

I also wasn't sure on the solar panels and how they need to be arranged. (series or Parallel; or both)

Based on what I do with the above will of course dictate the invertor being 24v or 48v.

I live in Oklahoma if that helps on the array as well.

Any help is appreciated. This is this first time with a large project like this. I watch tons of videos and read, but all of the numbers are starting to blur.

 

[snoobler]

Sounds like a big project. I assume you've done your homework and planned the system according to your needs and solar availability. If you haven't, you should.

60A is your charge current limit.

60A * 24V = 1440W
60A * 48V = 2880W

Both configurations will likely go a little above those, and limits will be stated in your SCC manual. You can also generally "over panel" to get your peak power for longer periods.

With MPPT controllers, you have significant flexibility. For panels in series, the series sum of your panels Voc MUST be under 150V, and they must allow for cold weather. It can get chilly in OK, so I would keep it under 125V.

I'm guessing those are 60 cell panels, so their Voc is probably around 40V. That would limit you to 3 in series. Then you just decide on 24/48 and parallel in as many strings as you can accommodate.


3S2P for 24V = 1560W
3S4P for 48V = 3120W

Since Leaf modules are 2 cells in series, they lend themselves better to 48V batteries since 14S with that chemistry makes for a good 48V requiring.

Critical that you get a suitable BMS. For maximum cycle life, you likely want to keep them between 3.5 and 4.05V/cell.

 

[cdunham]

I am wanting to use the power for an indoor greenhouse and the grow lights are 240 watts each. I have 12 grow lights. I am wanting to run them for 12-16 hrs a day if possible. At night, when they are not running, they would not being used at all.

 

[cdunham]

Yes, I would rather use a 48v battery system.

 

[snoobler]

Bummer. That's a MASSIVE load - about 1.5X the average American household. When one doesn't start with their needs and just starts guessing, this is what happens:

240W * 12 * 16 = 46,080Wh

You have about 4400Ah assuming they actually meet spec.

You need about 10X the batteries, and you have about half the solar you need.

 

[cdunham]

I am piecing it together, so not a major issue. I will just get more of what I need
I have all of the lights on grid and just wanting to move it to solar to save in the long run

 

[snoobler]

If it's about dollars...

46080Wh = 46.1kWh

Assuming $0.10/kWh, that's $4.61/day, under $1,683/year

Assuming you move forward with another 2X the panels, that's another $2500 used from SanTan.

You'll need enough charge controllers to handle about 380A, meaning another 5 of what you have, or upgrade to some bigger units - not cheap. Let's say $1200.

If you abandon the Leaf battery idea, which would be a good thing to do, and run with DIY LFP batteries, $6000

A quality 4kW inverter, $1500.

$11,200 = 6.6 year payback.

Now... given that you're not operating at night, you might be able to get away with a lot less battery UNLESS OK sun is unpredictable. Having spent the first 23 years of my life there, I would not describe OK weather patterns as "predictable."

Something to try would be to expand your solar first and opportunistically position maybe 4 arrays. E facing, SE facing, SW facing and W facing. You need to produce 3000W as long as you possibly can, and panels at different orientations may get you there.

Get an inverter/charger that will fall back to grid below a certain battery voltage.

By expanding your solar and charge controllers, which is typically cheaper than batteries, you may be able to get there faster than the conservative method requires. The only time you can't get it done is when you have bad weather. You're back on grid, but you're also providing SOME of your power via whatever solar you have.

 

[schmism]

I have 18 nissan leaf battery packs on the way... the specs are:

That sounds like you have 18 modules coming.

I typicaly call this a leaf battery

It is made up of a bunch of these "modules" which is in turn made up of 4 pouch cells in a 2P2S config.

^^those being the first gen version.

If you have 18 modules then your going to have 4 extra. Best config is a 14S which puts the battery pack voltage right in line for most 48v systems. However a 1P14S pack is only about 40ah.

You might check out my system build as I used leaf modules in mine.

 

[snoobler]

Good catch.

 

[cdunham]

That sounds like you have 18 modules coming.

I typicaly call this a leaf battery

It is made up of a bunch of these "modules" which is in turn made up of 4 pouch cells in a 2P2S config.

^^those being the first gen version.

If you have 18 modules then your going to have 4 extra. Best config is a 14S which puts the battery pack voltage right in line for most 48v systems. However a 1P14S pack is only about 40ah.

You might check out my system build as I used leaf modules in mine.

Where do i go to see your system build?