Solar Installation And Calculation

                               METHODOLOGY ON SOLAR PANEL INSTALLATION

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.

PV: Types of Solar Panel and Which one is the best PV Panel

 Now let’s begin,

Suppose,
Load = 1000Watts

Inverters Rating =?

Required Backup time for batteries = 3 Hours

Required No of Solar Panel =?

No of batteries =?

Solution:

Inverter should be greater 25% than the total Load

1000 x (25/100) = 250

1000+250 = 1250Watts

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 / 1000 W = 1.2 Hours

But our required Backup time is 3 Hours.

Therefore, 3/1.2 = 2.5→ i.e. approximately, we will now connect three (3) 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 3 Batteries = 3600 WH

 3600 WH / 1000 W = 3.6hours.

So this is a 36 V inverter system.  Now we will install three (3) batteries (each of 12V, 100 Ah) in Parallel.

Why Batteries in Parallel, not in Series?

Because this is a 36Vinverter System, so if we connect these batteries in parallel, then the Voltage of batteries (12 V) increases while it’s Ah (Ampere Hour) rating will be remain the same

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 +V3= 36V while the current rating would be same i.e.100Ah.

We will now connect 3batteries in series (each of 100Ah, 12V)

Therefore for 3 Batteries,

100 Ah 36V,

Now Required Charging Current for these three batteries.

 (Charging current should be 1/10 of batteries Ah)

100Ah x (1/10) = 10A

Now the required No of Solar Panels

P = VI

P = 36V x 10 A

P = 3600Watts

This is our required watts for solar panel (only for battery charging, and then battery will supply power to the load)

Now

360W/60W = 6 Solar panels

Therefore, we will connect 6 Solar Panels (each of 60W, 12V, 5A) in parallel.

Circuit Diagram for the above Calculation for Solar Panel Installation

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 (10 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,

10A + 10 A = 20A

Now I = 20 A, then required Power

P = V x I = 36V x 20A = 720Watts

(This is for both Direct Load and Batteries Charging)

Now,

720/60W = 12

Therefore, we will Connect 12 No of Solar panels (each of 60W, 12V, 5A)

And we use Charge Controller about ampere rating i.e., the charging current for 100Ah 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 based 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

By:  Emmanuel  S. Eshiet