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abdulnaeem74

 Nice place to learn for beginner for solar system setup

i have this system 
4 mono panels 150 watt  (2 in series for 24v system)
2 batteries 80Ah each
24v inverter/ups
30A PWM cm3024z solar charge controller china made

my questions are

a. can i install 4 batteries (100 Ah) for this system and with same charge controller
b. can add 2 more panels (150 watt) with same charge controller

mcgivor

Welcome to the forum 

Without details such as location, loads, depth-of-discharge, are you off grid, and if so how many days of autonomy  are required  etcetera and not calculating in losses, a basic answer would be:
a. 200Ah/24V battery  may be a little too large for the maximum  array you could safely use, 600W/24V 
b.You could use 2 more panels with the 30A controller to a maximum of 600W/24V 

This is a simple answer, provide all details listed and include panel specifications to get a more detailed calculation/estimate.
There are options such as adding a second charge controller in parallel with 2×450 W arrays to increase capacity but best to start with basics.

abdulnaeem74

Thanks for Prompt reply!

i live in Lahore Pakistan (ASIA), 
in summer Sun shine almost 10 hours  and temp almost 30-42 degree Celsius 
in winter sun shine 5-7 hours   and temp 10- 20 degree Celsius 

this is my panel specs  4 no. 150W mono-crystalline
VOC   21.5
Isc  9.83A
Vmp  18.5V
Imp  8.75A

i want my system to be off grid    
my load is 300 W per hour,
therefore i want to have 4 batteries of 100Ah  24v system
will it be ok with 30A PWM CC china made

and
can i add 2 more 150watt mono panels with same 30A PWM CC in future or have to replace Charge controller with 40A 

mcgivor

abdulnaeem74 said:

Thanks for Prompt reply!

i live in Lahore Pakistan (ASIA), 
in summer Sun shine almost 10 hours  and temp almost 30-42 degree Celsius 
in winter sun shine 5-7 hours   and temp 10- 20 degree Celsius 

this is my panel specs  4 no. 150W mono-crystalline
VOC   21.5
Isc  9.83A
Vmp  18.5V
Imp  8.75A

i want my system to be off grid    
my load is 300 W per hour,
therefore i want to have 4 batteries of 100Ah  24v system
will it be ok with 30A PWM CC china made

and
can i add 2 more 150watt mono panels with same 30A PWM CC in future or have to replace Charge controller with 40A 

One important  missing piece of information, 300W for how many hours, to establish your  daily watt hour requirements.

abdulnaeem74

6 hours specially in night

mcgivor

Sorry one more thing, are you using an inverter or are your loads DC, if you have  an inverter what is it?

abdulnaeem74

i am using APC UPS 1000va (24v)

mcgivor

Long answer short, adding 2 more panels will exceed the rating for your 30A controller, so yes a larger one would be required, 40A or more would be needed. The APC UPS is not an inverter per say, but I think I understand what you are doing, using  a salvaged UPS used as an inverter, on a budget, correct? As far as the hours  of sunlight are concerned you have to base it on the lowest figures for the year for an accurate estimate, and this depends on direction and angle, see link
As I'm not as well versed in estimating, as others such as @BB  I won't venture into that, hopefully the gracious Bill can assist, he is such a wizard at those calculations. 
http://solarelectricityhandbook.com/solar-irradiance.html

BB.

In general, I do not recommend UPS systems for use as off grid inverters... Many are MSW (modified square/sine wave) which can be hard on motors/electronic power supplies (something like 80% of loads may work fine, 10% may fail in hours/days/weeks, and another 10%--Who knows). And they are usually designed for 30 minutes of use or so (just long enough to ride through a short power outage and/or shutdown a computer system).

A small inverter (only available in 12 volts) that could work well for your needs (plus has remote on/off and a "sleep mode") is the MorningStar 300 watt 12 volt (120 VAC 60 Hz and 230 VAC 50 Hz models available) PSW (pure sine wave). If you can find something similar locally (this inverter may be hard/expensive for your to get)--I would suggest over a UPS.

http://www.morningstarcorp.com/products/suresine/

So--Some basic math. I will use 12 volt battery bank, but a 24 volt battery bank will give the same results (i.e., 12 volt @ 400 AH battery bank is the "same" as a 24 volt @ 200 AH battery bank--just different series/parallel connections, and/or different choice of battery voltage/capacity).

300 Watts for 12 hours with 2 days of storage (poor sun) and 50% maximum discharge seems to be a good "optimum" bank design for use with lead acid batteries. Deep cycle storage batteries should have 5% to 13% rate of charge typically. With 5% good for weekend/seasonal use. And 10%+ recommended for full time off grid use (better battery life, less day to day load management vs available sun):

• 300 Watt load * 6 hours per day night usage * 1/0.85 AC inverter eff * 1/0.77 solar panel+controller deratings * 2 days storage * 1/0.50 maximum discharge * 1/12 volt battery bank = 916 AH @ 12 volt battery bank
• 916 AH * 12 volts / 24 volts = 458 AH @ 24 volt battery bank

Now--I would suggest that over 800 AH battery bank should be converted to the next higher voltage--I.e., 458 AH @ 24 volts in this case... Either can work, but the 24 volt would be a better choice (less current, smaller battery / DC bus wiring). But, you need to find the inverter and charge controller needs to meet your needs (features/cost/availability). Anyway--Continuing on the math...

Next need to size the solar array based on two different calculations. First is based on battery bank capacity (5% to 13% rate of charge, base on 20 Hour battery rated Amp*Hour capacity). Using the above calculation:

• 916 AH * 14.5 volts charging * 1/0.77 solar panel+controller deratings * 0.05 rate of charge = 862 Watt array minimum
  
• 916 AH * 14.5 volts charging * 1/0.77 solar panel+controller deratings * 0.10 rate of charge = 1,724 Watt array nominal
  
• 916 AH * 14.5 volts charging * 1/0.77 solar panel+controller deratings * 0.13 rate of charge = 2,242 Watt array "cost effective" maximum

And then there is sizing the array based on your daily loads. For your region:
http://www.solarelectricityhandbook.com/solar-irradiance.html

Lahore
Average Solar Insolation figures

Measured in kWh/m2/day onto a solar panel set at a 58° angle from vertical:
(For best year-round performance)

Jan	Feb	Mar	Apr	May	Jun
4.72	5.66	6.16	6.50	6.68	6.34
Jul	Aug	Sep	Oct	Nov	Dec
5.52	5.46	6.00	6.43	5.73	4.91

Based on 300 Watts * 6 hours per day or 1,800 WH per day and a minimum and 4.71 hours per day (January long term 20 year average):

• 1,800 Watt*Hours * 1/0.52 off grid system eff * 1/4.72 hours of sun per day (noontime equivalent full sun) = 733 Watt minimum array
  

Because you have a lot of sun in your area--Your minimum array should be at least 862 Watts minimum if you charge during the day (mostly) and run most of your power at night to ensure that the battery bank gets a minimum rate of charge.

If you will run more power during the day (say water pumping, laptop computer, etc.)--Then you may want to get towards 1,724 Watt array.

The above would be a "nominal" designed system with lead acid batteries for full time off grid. If the system is only used for weekends or a week or two at a time--You might be able to get away with a smaller battery bank (1/2 the AH ratings I calculated)...

-Bill

abdulnaeem74

its very nice that much you guided. i wl make it possible in next year with more PV array and batteries..
keep smiling