Solar Panel Installation: Step by Step Procedure
- A Complete Guide about Solar Panel Installation
A Complete Note on Solar Panel Installation. Calculation about No of Solar Panels, batteries Rating / Backup time, Inverter/UPS Rating, Load and required Watts. with Circuit Diagrams.
If you pick this post related to solar panel installation, You will be able to;
→ To calculate the no of solar panel (with rating)
→ To calculate the rating of Solar panel
→ To calculate the rating of batteries for Solar panel system
→ To calculate the back up time of batteries
→ To calculate the charging current for batteries
→ To Calculate Charging time for batteries
→ UPS Rating for load requirement and much more…
Before starting, We recommend to read this Article about Solar panel installation and Photovoltaic Pane Selection for home.
Now lets begin,
Load = 800 Watts
Inverters Rating =?
Required Backup time for batteries = 3 Hours
Required No of Solar Panel =?
No of batteries =?
Inverter should be greater 25% than the total Load
800 x (25/100) = 200
800+200 = 1000 Watts
This is the rating of the UPS (Inverter)
Now the required Back up Time in Hours = 3 Hours
Suppose we are going to install 100Ah, 12 V batteries,
12V x 100Ah = 1200 Wh
Now for One Battery (i.e. the Backup time of one battery)
1200 Wh / 800 W = 1.5 Hours
But our required Backup time is 3 Hours.
Therefore, 3/1.5 = 2→ i.e. we will now connect two (2) batteries each of 100Ah, 12V.
If the number of batteries given, and you want to know the Backup Time for these given batteries, then Use this formula.
1200 Wh x 2 Batteries = 2400 Wh
2400 Wh / 800 W = 3 hours.
So this is a 12 V inverter system, Now we will install two (2) batteries (each of 12V, 100 Ah) in Parallel.
Why Batteries in Parallel, not in Series?
Because this is a 12Vinverter System, so if we connect these batteries in parallel, then the Voltage of batteries (12 V) remains same, while it’s Ah (Ampere Hour) rating will be increase
(Remember: In parallel Connection, Voltage will be same in each wire or section, while current will be different i.e current is additive e.g. I1+I2+I3…+In = 100Ah +100Ah = 200Ah
In Series Circuits, Current is same in each wire or section while voltage is different i.e. Voltage is additive e.g.V1+V2+V3….Vn..
For The above system if we connect these batteries in series instead of parallel, then
The rating of batteries become V1+V2 = 24V while the current rating would be same i.e.100Ah.
We will now connect 2 batteries in parallel (each of 100Ah, 12V)
Therefore for 2 Batteries,
200 Ah 12V,
Now Required Charging Current for these two batteries.
(Charging current should be 1/10 of batteries Ah)
200Ah x (1/10) = 20A
Now the required No of Solar Panels
P = VI
P = 12V x 20 A
P = 240Watts
This is our required watts for solar panel (only for battery charging, and then battery will supply power to the load)
240W/60W = 4 Solar panels
Therefore, we will connect 4 Solar Panels (each of 60W,12V,5A) in parallel.
Circuit Diagram for the above Calculation for Solar Panel Installation
Click image to enlarge
This was only for battery Charging (and then battery will supply power to the desired Load) i.e. for those electrical appliances, which will get power through inverter (from charged batteries)
Now suppose there is some (Directly connected to the panels through inverters (without battery) load about 10A, which we have connect directly to the solar panel (No batteries required)
In this case, required current (20 A for Batteries Charging and 10 A for direct connected load through Inverters during sunshine only but batteries will be also charging while panel supply power to the direct connected load.
In this case, total current,
20A + 10 A = 30A
Now I = 30 A, then required Power
P = V x I = 12V x 30A = 360Watts
(This is for both Direct Load and Batteries Charging)
360/60W = 6
Therefore, we will Connect 6 No of Solar panels (each of 60W, 12V,5A)
And We use Charge Controller about ampere rating i.e, the charging current for 200Ah battery is 20-22 Amperes (22A (For Battery Charging)+10A(for direct DC Load)…So we can use a charge controller about 30-32 Amp.
Note: this calculation is base on ideal case, so it is recommended to always choose a Panel some bigger then we need. Because when Solar Panel charges the battery so it is wasting some power on charging too.
this is another Circuit Diagram for the above Calculation for Solar Panel Installation
Click image to enlarge
By: Engr Wasim Khan
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