Need Help Noob

wpmaura

Long story short need help setting up a relatively simply solar system. There is not any really around to help with this. I have managed to piece this all together and need to know if this will work.

I have 6x270 watt Panels

4 12v 100amp gel batteries

this is the inverter I managed to get

https://www.amazon.com/Inverter-3000Watt-120Volt-Display-GIANDEL/dp/B07JQKQQTP/ref=asc_df_B07JQKQQTP/?tag=bingshoppinga-20&linkCode=df0&hvadid=&hvpos=&hvnetw=o&hvrand=&hvpone=&hvptwo=&hvqmt=e&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=&hvtargid=pla-4583795263702631&psc=1&th=1

and the charge controler is a ps 30 12/v24v and older one no lcd display at all.

I am fairly sure all I need to do is to wire the batteries in series/parell in order to get to 24v, after that its just wiring everything correctly. I would like to know if everything I have above will work, should I run the panels series or paralell? Any help would be apreciated.

Take in mind ordering new stuff really is not an option.

BB.

Welcome to the forum wpmaura,

Can you tell us a bit more about your energy needs (type of loads, peak Watts, how much energy do you need in Watt*Hours per day, rough location, seasonal/year round usage, etc.)...

Can you give us the Vmp/Imp ratings of the panels (something like 270 Watt panel, Vmp=30 volts, Imp=9 Amperes).

Do you have a link/brand/model for your GEL batteries (in the US, many GEL batteries have limited allowed charging current).

And need more information on your Solar Charge controller (PWM or MPPT type controller).

-Bill

wpmaura

generic Chinese batteries, I only really need this thing to run the fridge as long as possible, panels say 30vmp 9amp, charger is PWM

this is the specific fridge

https://www.lg.com/us/refrigerators/lg-LFC24770SW-french-3-door-refrigerator

long story short live in the Bahamas and about 3 months the island we were on got wiped clean, power is still months away and burning gas for generator aint cheap to keep fridge running. So trying to get something up and working that will allow the fridge to work and few other things, will still need generator for water pump

BB.

I am sorry to hear that your post storm power issues are still ongoing.

The first issue is that we need to know if the Vmp of your panels is 30 volts or 36 volts (typical solar panel voltages for those size of panels).

If they are Vmp~30 volts, then if you have a PWM (less expensive) solar charge controller, it will not work with a 24 volt battery bank (or at least, not very efficiently).

If you have Vmp~36 volt panels (72 cell panels), they will work fine with a PWM solar charge controller on a 24 volt battery bank.

Your refrigerator is a 606 kWH per year unit, or:

• 606,000 WH per year / 365 days per year = 1,660 WH per day fridge (usage, ambient temp, making ice, etc. all effect energy usage).

Your 24 volt @ 200 AH GEL battery bank stores:

• 24v * 200AH = 4,800 WH per day

Your fridge + inverter uses (very roughly):

• 1,660 WH per day * 1/0.85 AC inverter eff = 1,953 WH of battery power per day
• 1,953/4,800 WH of battery storage = 0.41 = 41% of battery capacity

That is a bit much to take from a battery bank cycling long term (suggest 25% of capacity per day)--But in a very sunny climate with genset backup for bad weather, should be doable...

If you have a good match for Solar panel Vmp and Charge Controller type, your array should produce something like (fixed array, facing south, average weather conditions):
http://solarelectricityhandbook.com/solar-irradiance.html

Lucaya
Average Solar Insolation figures

Measured in kWh/m2/day onto a solar panel set at a 64° angle from vertical:
(For best year-round performance)

Jan	Feb	Mar	Apr	May	Jun
4.72	5.50	6.08	6.49	6.44	5.86
Jul	Aug	Sep	Oct	Nov	Dec
6.08	5.96	5.69	5.62	4.95	4.45

For November:

• 6 x 270 Watt panels * 0.52 average AC system off grid eff * 4.95 hours of sun = 4,170 WH of "useful" solar harvest per day

I suggest that you plan on using for your base loads (daily loads that must run) something like 50% to 65% of your predicted solar harvest:

• 4,170 WH * 0.65 base load fudge factor = 2,710 WH "base load"

Which is >1,660 WH of the fridge by itself... So that looks OK.

Your solar array, on average, will probably produce a maximum average of:

• 6*270 Watt panels * 0.77 controller+panel deratings * 1/29 volt charging = 43 Amps 

So this gets back to the charge controller... If this is a 30 amp charge controller, you have too many panels for that controller. And if the panels Vmp vs PWM/MPPT is a wrong match, need to get different panels or different charge controller (or different/larger charge controller).

MPPT (maximum power point tracking) charge controllers can safely/reliably limit their output voltage. PWM controller cannot, and for this array, you would need a larger PWM controller. Also MPPT charge controllers can "efficiently" take high voltage/low current from the array and Down Convert to the low voltage/high current to charge your battery bank--PWM controllers cannot.

And wiring wise--If you plan on using all 3 kWatt of your inverter's output:

• 3,000 Watts * 1/0.85 inverter eff * 1/21.0 volt low battery cutoff = 168 Amps of current draw (2x that for starting surge)

You need heavy cable/short cable to carry that much current reliably.

And, I did not see it... But there may be an issue with your AC inverter. Larger inverters can have higher "tare losses" (the energy usage from being turned on with no loads)... For this size inverter 20-40 Watts is not uncommon. The total losses for 24 hours could be:

• 40 Watts * 24 hours per day = 960 Watts 

Or over 1/2 of your refrigerator loading. Keep track of the current drain on your battery bank... And your battery state of charge. It could be very easy to drain your battery bank with one day of no-sun...

And, I highly suggest you get a DC Current Camp Digital Multi-Meter... Especially since you do not have a display on your present charge controller. A current clamp DMM is very easy and safe to use... You simply clip the clamp around a single conductor, and measure the current.

Note there are AC only current clamp, and AC/DC current clamp meters. The descriptions can be a bit confusing (AC clamp meter, AC+DC volt meter--Not what "we" want here). It will make diagnosing and monitoring your solar power system much easier. Here are a couple of examples of the type of meter:

https://www.amazon.com/gp/product/B019CY4FB4 (nice, mid range meter for $130)
https://www.amazon.com/gp/product/B07546L9RT (good enough for our needs $40)

And, it does not hurt to have a Kill-a-Watt type power meter to estimate your AC loads:

https://www.amazon.com/s?k=kill+a+watt

Above links are just suggested starting points. Who you purchase from and what specific products are your choice.

Lots here... Feel free to ask questions and correct my guesses.

-Bill

BB.

Whoops, after typing all that, I see your very first item is Vmp=30 volts and Imp=9 amps. And PWM charger...

That is not a good match... Solar panel output voltage drops as the panels get hot (i.e., daily use in sun)... Vmp-hot can drop to as low as 24 VDC. And your batteries need (nominally) around 28.4 volt to charge (plus a few volts for controller and wiring drop).

Normally, you would put 2x panel in series (Vmp-array-std = 60 volts) and three parallel strings (9 amps per string, 27 amps total).

If you used 6x panels in series, you will not get rated charging current.

If you use 2s x 3p panels, your PWM controller (if it could "manage" the higher array input voltage) would lose about 1/2 of the solar panel output energy (it is how MPPT and PWM controllers work).

I suggest you need to get an MPPT type charge controller with, at the very least, 40 amp output... But ideally 50 amp or more output (especially if you may add solar panels later).

MPPT controller are "expensive" vs PWM, but for your system hardware and configuration, it is just about mandatory you get one to have a successful installation.

-Bill

wpmaura

is there an mptt charger your recomned?

wpmaura

looks like I am able to source this

https://www.amazon.com/gp/product/B07BRD4DY8/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

curious are you supposed to wire inverter into charge controller or inveter into battery?

Estragon

The inverter should be wired to the battery, with a properly sized DC rated breaker on the positive wire.

wpmaura

Estragon said:

The inverter should be wired to the battery, with a properly sized DC rated breaker on the positive wire.

Estragon said:

The inverter should be wired to the battery, with a properly sized DC rated breaker on the positive wire.

Excuse my ignorance but what is the risk of not having a DC rated breaker and is exatcly what is it.

BB.

Some youtube videos. 220 VAC knife switch arc vs 220 VDC knife switch arc:

https://www.youtube.com/watch?v=Zez2r1RPpWY

Example of AC breaker running DC voltage and manual trip:

https://www.youtube.com/watch?v=csMQ9A-4Pws

Many DC breaker are also polarity marked (newer are supposed to not have a polarity requirement?):

https://www.youtube.com/watch?v=Cup5fMGaE2g

More or less, at ~12.0 volts, is the minimum "Arc Sustaining" Voltage (is somewhat material rated--Copper, silver, gold, etc. contacts)... So any voltage >12 volts, you need to look at the DC voltage rating (typically lower than the AC voltage rating).

-Bill

Photowhit

I that charge controller doesn't work well with those panels. It has  a  max  input voltage of  100v,   This would be the VOC, which is likely around 38-40 volts and a string of 3 would put it over 100 volts.

Manual;
https://www.renogy.com/template/files/Manuals/Rover 203040 Manual.pdf

wpmaura

Photowhit said:

I that charge controller doesn't work well with those panels. It has  a  max  input voltage of  100v,   This would be the VOC, which is likely around 38-40 volts and a string of 3 would put it over 100 volts.

Manual;
https://www.renogy.com/template/files/Manuals/Rover 203040 Manual.pdf

well the panels are 30volts, and if do 2 in a series then parell them thats 60 volts correct. What would people recomend then for the best inverter and charge controller for what I currently have?

mike95490

wpmaura said:

well the panels are 30volts, and if do 2 in a series then parell them thats 60 volts correct. What would people recomend then for the best inverter and charge controller for what I currently have?

We are now washing the cat, trying to figure how to get mismatched parts to work, with totally unknown loads.

This can be made to work, but there will be lots of manual load management to not overly discharge the batteries so much that they cannot be recharged in the next day.  Without buying new components that will work well together,

wpmaura

what components work together then.  As is that set i have for the pannels incorrect?

wpmaura

Also take in mind I only want to use this primarly for the day, at night I will switch generator on for 5 hours to run fridge, But if someone can tell me the components I need to maximise this system i would apreciate it.

mike95490

First thing we need to know is your loads.  Load totals for daytime 6 hours, and night loads 18 hours.

Photowhit

wpmaura said:

Photowhit said:

I that charge controller doesn't work well with those panels. It has  a  max  input voltage of  100v,   This would be the VOC, which is likely around 38-40 volts and a string of 3 would put it over 100 volts.

Manual;
https://www.renogy.com/template/files/Manuals/Rover 203040 Manual.pdf

well the panels are 30volts, and if do 2 in a series then parell them thats 60 volts correct. What would people recomend then for the best inverter and charge controller for what I currently have?

You  are correct, forgot  this was  a 24 volt system... sorry.

Don't  know  the size, type  or load of the fridge, but I would sure shoot for  the solar electric system to handle the load over night, at least when you are expecting sunny  days.