Help with my diagram and plan

[offgridcab]

Hey All,

I am finishing up the power plan for my weekend cabin and this is my first system and I am not an expert by any stretch.

Please look at my diagram and tell me if I am missing or have mistakes (awg gauge, missing breakers, and so on). As you can see I do not have anything there fro the solar panels yet since I need your kind help with planning those.

Bank will be 4x 12V 200AH renogy AGM creating 24V 400AH bank. I will have 900w-1200w array. I just recently decided to also have panels - before I just wanted to charge using my generator since this is a weekend cabin. My knowledge of solar is very slim.

I was blown away by the price point and all in one capabilities of the LV2424. Seems to be truly an amazing device.

My cabin is in upstate NY (gets very cold). My plan is to use it during non winter months for the next 2-3 years then start using it in winter later on. When I leave cabin for winter I will leave batteries "full" and everything switched off. During "season" - only thing I need to keep running while I am away is the 24v fan that draws 0.1ah. In winter it will not be on obviously.

Basic questions about array:

• I found some craigslist used panels for dirt cheap... 265w for $75. Seller claims they are tested and work well. I also found new panels locally that are 420W for $210. Are used panels a no no? what should I inspect and test when I go look at them?
• if I buy 3x 420w panels: can I wire two in parallel then in series with the 3rd to keep my voc under 100? In general I can mix like that however I want or is that an issue?
• I will measure but I think my panels will be about 50ft away from lv2424. If I have about 100voc - that means I can run a 10awg?
• Do I need a breaker between panels and lv2424?

Questions about LV242:

• Does it come with a temp gauge for batteries? can it be set to not charge at certain temp?
• If I plug in the generator to it: then will it charge the batteries and use power from generator to feed my ac loads? can it be set to not draw more than a certain amp from generator to prevent it from overloading generator?
• I believe in my set up that my batteries will be recharged when they hit 80-85% very often which I read about not being very good for batteries (shallow charging?). Can I set it to only start charging when they reach a certain SoC - preferably 75% SoC? My usage is so low at the cabin (I measured) and I visit it about 25 times a year that I think that going to 50% SoC won't mean much for me since the batteries will naturally die before I reach anywhere near the cycle amount listed for 50% SoC.
• Is it possible to wire or buy for it a remote on off switch?
• It doesn't say anything about search mode. Does it have search mode so it can run at very low watts draws when there is barely any usage?
• Can you set it to switch off and not feed ac loads if batteries reach a low SoC? to protect batteries of course.
• if I have the generator hooked up - how does it power my panel? will it switch to batteries when genset ravs up? (also called generator assist?) since the generator takes a min to get to full rpm. It is a honda 2000eu
• does it connect to a computer for settings adjustment? does it require some kind of dongle for that?

I apologize if many of these have been answered but I always like to ask in case I find an old answer that has since been changed.

Thank you

 

[offgridcab]

 

[Wellbuilt]

Your plan looks ok , but the genarator should go to the inverter and the inverter
Should pass power to your loads and charge the battery’s .
Your fuse should be on the positive battery lug , they make a fuse for this .
You will need 2 one on each series battery
I would buy as many solar panels as the charge controlers can handle .
I’m thinking 2000 watts +- I bought new 295 watt panels for 135$ and 165 $ a few years ago .
All the answers to your questions are in the manual on line .
Where are you in my state I have a place in Monroe in the Catskills and in lake George
I’m off grid year round in the cat skills
The day after thanks giving it like some one turned the sun off ? I start getting power back the second to last week in January .
Then it snows every day and covers my panels . ? last year I ran a genarator every morning for 10 weeks .
The year before we did not have much snow .
Where are you located ?

 

[offgridcab]

Hey there

Yeah the inverter is fed by generator. The other one is a bypass if batteries are too low and I want to run my cabin on my generator exclusively if there is an issue. Yup breaker is indeed on the positive. The other thing on the negative is a shunt for the battery gauge.

I am near port jervis. Where did you pick up the panels? Locally or is that a shipped price?

You ran it every morning so you are there full time? Mine is a weekend getaway. I have been running off the generator when I am there using an extended tank. I want batteries and inverter just for the complete silence and prevent brownout on fridge and ac.

I have a 120v ductless system I installed myself. Works perfectly and uses very little power. My fridge is a freezer conversion.

I used a kill-a-watt on my generator to measure how much power I used. In a 3 day weekend (2 nights) having fridge 24/7 and ac on for 12 hours a night (granted it was cool so it didn't work hard at all) - I used 5kwh.

 

[Wellbuilt]

my panels came from a electric supply house in Goshen New York
just up rt84 green mountain electrical supply . 6588 Ryan
I buy from ryan over the phone and they send the equipment to goshen ny for (no charge ) I was getting 295 watt panels for 167 $ each last year .
I don’t know if you are getting inspected by my state but this fuse passes inspection.
You need 2 one for each battery bank positive .
Just looking again i would make all the battery cables 2 g
I’m pretty sure your inverter has a generator pass thru , I just start my generator and turn on AC power and the charger charges the battery and allso powers loads .
As far 2g cables go you should by them on line pre made with the ends crimped on .
It only cost a few bucks more And you won’t have problems with bad connections that heat up .
your panels must match system voltage , so your pannel voltage must match your 24v system .
Your charge controller take100 volt in put , so to 40 volt panels can go on a 100v charge controller
It’s cold here and your voltage gos up in the cold ? if you have 2 strings of solar you don’t need breakers in the line .I would add as much solar as possible , its money in the bank .
I’ve never had any one tell me they have to much solar power ?.
I’ve been working at my place, so I was up state for weeks at a time last year .
5k seams light for a fri night sat and Sunday half day .
You Will probably need to make 7k + with solar /inverter losses .
1200 watts of solar seams light to me , it would give allmost 1000 watts a hour for 4.5 hours so 4500 watts +- per day in may , jun , July , and on dec 21 you will get 2.5 hours of sun 2500 watts or a bit more
you will have to run the generator early morning for a hour to boost power so the sun can get you to full power
I skimmed over the manual and it looks ok .

 

[offgridcab]

Thanks for info.

I found a guy in Long Island. He has 420w bifacial panels, brand new, for $210. I am thinking to get 4 from him. So I will have over 1600watts.

If I understand this correctly, and please correct me if I am wrong, I can wire two pairs of panels in parallel then hook those two pairs in series which will keep me right under 100voc (each panel is about 48voc). Is that correct?

I know this all in one can handle up to 150v but won't charge if it over 115v so this seems to be the sweetspot.

What batteries you got? i will get the renogy 12v 200ah agm I think. Seems to be the best price and i can get from home depot so I can return easy if there is an issue.

What do you mean two fuses for positives? In my diagram I have a 170am circuit breaker (same as fuse but can be reset so it can act as an isolator) on my positive line between batteries and inverter. Then I am guessing another one between panels and mppt.

I am not sure if I need to figure out some kind of heater for batteries in winter?

 

[Wellbuilt]

I was looking at the specks in the manual and I read it as 100 volt mppt charge controller with 2 string input .
I may have been looking at the wrong unit , I was thinking the larger 48 volt system had the 150volt charger .
If you have 150 volt charger 2 48 volt panels would be ok .
There is a max wattage you need to stay under I did not see it listed so ( check it out ) .
Those panels from Long Island are made to get power from the bottom so the need to be mounted up 4’ with a reflective service under them like white sand they really need to be ground mounted .
I think I would pass on them and find some regular panels .
I think if you series / parallel those panels for 1600 watts you would need a larger then 10 g wire .
You do have 2 inputs so you could just run 2 strings all the way to the panels .
I bought a large spool of solar wire from the supply house in goshen with the ends that fit on my panels .
I would use the fuse above one on each battery and add a on off switch in stead of breaker , I think there is a on off switch on the inverter.?

The 200 amp hr regency battery’s are 1600 bucks

I use Duracell 6 volt 215 amp hour battery’s So 8 battery’s @ 6 volt these arentough battery’s for half the money .
They will last 5 years to 3 or 4 years on the agms .
You can check them add water . I would use these for your first set in case you Murder them somehow.
My battery box is large enough for 2 rows of L 16 battery’s in case I need more power .
Notice the fuses on the battery’s at the end of the red wires and the distribution block .
I have a power vent on the end of the pvc pipe that turns on automatically and blows out side when in absorb charge mode .
The batterys don’t gas off much i leave the lid open this time of year , in the winter it stays closed.
My box is in my garage , it gets below zero in there and the battery’s can be zero .
When they are cool i have less capacity and I charge at a higher voltage .
But if they are full charged or cycling they can’t freeze .
I turn every thing off if I’m home working .
If I’m using the system it stays 47o even if it’s 25 below out side .
I use out back equipment and it really works good .
I don’t know a lot about the all in one Chinese systems yet .
depending on how large your place is and what loads you need to power determines your system size and voltage.

My system.

 

[offgridcab]

Wow man you have a real cabin there. Mine is 144 sqft haha! 12fx12f. Tiny house... Ac is off during the day so it is just two led lights, freezer conversion, and tiny fan for toilet... that's why it is such low draw. At night in summer we run ductless whos also very efficient at 22 seer.

I will look into those fuse locations.

Thanks for the tip about the bifacials. I will read up about it.

I believe I need a 30am breaker between my panels and inverter.

 

[Wellbuilt]

Panels get this box and breakers one per string , @ 50’ I would just mount the box next to the inverter inside and run 2+ 2-
10g solar wire . It comes in 500 ‘ rolls
You will need 200 feet min so you will have extra . But it’s cheep .
If your cabin is not on wheels the building dept will find you .
They are funny about the tiny house thing in New York .
I’m on top of a Mountain in the middle of nowhere and it took them 2 weeks to find me .
Every one start at the bottom of the ladder
And works there way up .
I stayed in the old air stream trailer for the first few years .
Some mornings my pillow and blankets would be frozen to the wall .
Some solar on the roof , water system?
Out house .
I built the place with my son
Most of it I framed with rough sawn lumber
I was reading up on your inverter and I saw that it is has a 80 charge controler there are guy running 2700 watts of soled thru them .
There is a guy on Craigslist that sells old cast iron wood stoves in your neighborhood I think you will need to burn wood to get warm , it take me a week to warm my place up in January running a big
Wood stove wide open .
Once warm I can heat it with a few splits .
I would look for 300 watt panels in the 40 volt range , the voltage is a little hi but you will get the most watt of solar on 2 strings of 3 for 1800 watts
Then if you need more power you can add
3 more and max out your charge controller at 120 volts or a bit more you won’t burn up the 150v max voltage charge controller .

 

[MisterSandals]

I can wire two pairs of panels in parallel then hook those two pairs in series

If you wire 2 in series and then hook those two pairs is parallel, your array will be better setup for partial shading. With 2S2P, the 2 parallel strings will be independent and unaffected if the other string is partially shaded.
As you have your above plan, if any 1 panel of the 4 is shaded, the entire array will be compromised.

 

[MisterSandals]

I believe I need a 30am breaker between my panels and inverter.

I would not exceed the "max string fuse" rating specified on your panels. Its probably around 15A.