All in One and Battery advice

[hbulle13]

Hello. I bought a cabin in Montana with no possibility of grid electricity. The previous owner built the place and wired the cabin and barn. She ran it off a 7000 watt Honda generator when needed, but mostly lived without electricity. I want to install solar to run most things and leave the generator as a backup. I ran through several calculators and came up with a max 7kWh per day in the summer and less in the winter. I ordered forty 250W used panels from SanTan solar. (I figured I could use any spares for other projects). These are rated for 30.3V at 8.27A, but I assume reality will be somewhat less given they are used and I am in Montana. There is a breaker panel(Attached) and it is wired from the Generator with Split Phase 220.
1. How many panels should I mount? I was thinking 20, but I am unsure how to calculate overpaneling due to Latitude and older panels?
2. All in one system? Growatt 2x4500W split phase package or MPP 6048 6Kw.
3. Batteries - I will not need a ton of night or low sunshine power and I can run the generator if needed, so I was going to spend the most on the All-in-one and build up batteries over time, but I want good ones. IF I have $2000 for batteries to start, what would you recommend, given that I will add to it next year to get to a total of 21KwH of storage.



Thanks everyone.

 

[coil1002]

First thing I would do is see how many I could use per System this will help with that

PV String Calculator | AERL

www.aerl.com.au

Then I would use as many as I could. Its way better to have more power than you need, than the other way around then you could slowly build storage as you need it or hell just have a big ole light party with al that extra energy.

I have never used either of those systems I have 2 MPP lv2424 there 2400 w a piece. There where parallel connected so I could get split phase but I never use 220 when I am on solar so I took the boards out. YMMV

If your handy with electricity I would say buy the raw cells and build your own storage. It is the cheapest option. If not there are a plethora of good prebuilt now a days but I have not used any so I will leave that to someone with experience to suggest.

That cabin looks amazing by the way

 

[coil1002]

I will say I love my MPP system but the idle current is high about an amp

 

[Just John]

Most people report the used SanTan panels as being "good as new", but they may just be seduced by the good price.
For $2000 you should be able to get about 12-13 KwH of storage and a BMS. (I paid $1600 for 16 Eve cells last year).

Not sure about these yet, they are so new:

MPP LVX6048 Hybrid Inverter Split Phase 120/240VAC 48V | SanTan Solar

store.santansolar.com

 

[MichaelK]

Will you be running a well-pump, or other 240V appliances? Since the previous lady wired the cabin as split-phase 120/240VAC, a split-phase 120/240V inverter would be a good fit. Will you be running tools/appliances with electric motors? A lot of AiO inverters are less-expensive high-frequency units that do not have good surge capacity for starting large electrical motors. Here are some split-phase inverters that I myself would be glad to have.

Magnum Energy MS4448PAE Sinewave Parallel Inverter - RES Supply

Free Shipping! Magnum Energy MS4448PAE Sinewave Parallel Inverter, 4400W, 48V, 60Amp PFC Charger, 120V/240V, 60Hz

ressupply.com

Schneider Electric Conext SW4024-120/240 Inverter/Charger - RES Supply

Free Shipping! Schneider Electric Conext SW4024-120/240 Inverter/Charger, 4000W, 120/240VAC, 50/60Hz, 30A Transfer, 24VDC, 90A Charger, RNW8654024

ressupply.com

OutBack GS4048A-01 Radian Inverter/Charger - RES Supply

Low Flat Rate Shipping! OutBack GS4048A-01 Radian Inverter/Charger, 4000W, 120/240VAC, 60Hz, 50A Transfer, 48VDC, Sinewave, 57A Charger, with BTS, Dual AC Inputs, ABC, GridZero Technology, UL1741-SA, Powered Coated Finish

ressupply.com

Schneider Electric Conext XW Pro 6848 NA (865-6848-21) Inverter/Charger - RES Supply

Low Flat Rate Freight! Schneider Electric Conext XW Pro 6848 NA (865-6848-21) Inverter/Charger, 6800W, 120/240VAC, 50/60Hz, 60A Transfer, 48VDC, Sinewave, 140A PFC Charger, With BTS, UL1741-SA, 865-6848-21, RNW865684821

ressupply.com

OutBack GS8048A-01 Radian Inverter/Charger - RES Supply

Low Flat Rate Shipping! OutBack GS8048A-01 Radian Inverter/Charger, 8000W, 120/240VAC, 60Hz(50Hz), 50A Transfer, 48VDC, Sinewave, 115A Charger, with BTS, Dual AC Inputs, ABC, GridZero Technology, UL1741-SA, Powered Coated Finish

ressupply.com

I myself own both of the Schneider inverters listed, and I am very happy with them.

Let's assume you get 2.5 sunhours (SH) in Montana in winter, and 5.0 in summer. You want to plan on making power on your worst day, not your best. Assuming you want 7000Wh and you have 2.5 sh of solar, then you'd need 7000Wh/2.5sh = 2800W of panels. Call that 12 of your 250W panels. I mounted my panels on rotating single pole arrays. This design pic shows four 250W panels, but it will hold six in the portrait orientation.

Actually, if you rotate the array East to West over the course of the day, I'd expect just one 1500W array to make 7000Wh. But, since you already ordered 40 of them, you could do at least two.

Use a string calculator to determine what your winter low temps will be which will effect your winter Voc. I like Midnight Solar's calculator.

MidNite Solar - Classic Sizing Tool.

MidNite Solar is the industry leader and manufacture of quality Renewable Energy System electrical components and E-Panels.

www.midnitesolar.com

You could wire three panels in series with 2 parallel strings of three (3S2P), for a Vmp of ~90V. The Voc below freezing though will be >120VDC, so don't buy a controller with a 100V limit. I wired my panels in 4S, with a Voc in winter of ~160Voc. I have Midnight200 controllers.

For batteries, you could start with Costco 6V-210Ah golf-cart batteries. Eight of them would be 800$ plus tax and core charges. The next step up would be Trojan L-16 batteries 6V-375Ah.

Assuming you don't want to ever use more than 50% of your battery, and you want at least 2 days of autonomy, the math works out to be...
For Costco, (210Ah X 48V X 0.5Capacity)/2 days = 2520Wh, or 2.52kWh
For Trojan, (375Ah X 48V X 0.5Capacity)/2 days = 4500Wh, or 4.50kWh

At my own cabin, I find myself using about 3.0kWh per day, so Trojans were my first choice. I've since upgraded them to 568Ah Rolls. Now I can run my air-conditioner all night without serious battery depletion.

 

[hbulle13]

First thing I would do is see how many I could use per System this will help with that

PV String Calculator | AERL

www.aerl.com.au

Then I would use as many as I could. Its way better to have more power than you need, than the other way around then you could slowly build storage as you need it or hell just have a big ole light party with al that extra energy.

I have never used either of those systems I have 2 MPP lv2424 there 2400 w a piece. There where parallel connected so I could get split phase but I never use 220 when I am on solar so I took the boards out. YMMV

If your handy with electricity I would say buy the raw cells and build your own storage. It is the cheapest option. If not there are a plethora of good prebuilt now a days but I have not used any so I will leave that to someone with experience to suggest.

That cabin looks amazing by the way

I am trying to decide if I really need 6kW inverter or if I can do with less. The only issue, I think, is my well pump and I can always turn on the generator for that. I only get 40 Gallons a day and it is very alkaline so only used for dishes and showers etc. I collect Rain water for plants, chickens, etc.

 

[hbulle13]

Most people report the used SanTan panels as being "good as new", but they may just be seduced by the good price.
For $2000 you should be able to get about 12-13 KwH of storage and a BMS. (I paid $1600 for 16 Eve cells last year).

Not sure about these yet, they are so new:

MPP LVX6048 Hybrid Inverter Split Phase 120/240VAC 48V | SanTan Solar

store.santansolar.com

I went with 4 x 12V 200Ah Amperetime batteries. It was more than I wanted to spend, but this is my first solar attempt and I wanted to be responsible for as little as possible. That is why I am going with an All-in-one and batteries that are recommended by this site.