How to choose the solar panel?
Posted on: 2015-11-03 21:52:31

As we know, we want to use solar energy, there are solar panel, batteries, solar charge controller, solar power inverter in the solar system. But how can we make the solar system? Firstly, we should know the power of your need, then we can know how to choose the solar panel.

Some clients asked us how to choose the solar panel. We have answered here.

Of course, it’s a rough way only for your reference. The more accurate algorithm is to calculate the solarpanels’ generate power.

Solar panels capacity refers to the plate type solar panels power generation power (Wp). Solar power value depends on the power which the loads consumed in 24 hours. The loads’ rated power supply and the loads’ 24hours consumption electricity decide the consumption capacity P 24 h (AH) of the loads in 24 hours. And considering the average sunshine hours every day and rainy/cloudy days affect. Then calculates the working current IP (A) of the solar array.

Judging by the rated power supply, select the battery nominal voltage. And from the battery’s nominal voltage,we choose how many batteries we need and the batteries’ charging float series pressure VF (V), and considering the solar batteries’ temperature of voltage VT (V) which caused by the temperature rising and reverse filling diode P-N pressure drop of VD (v), the impact of the solar array may be calculated the working voltage of VP (v), the solar array work power IP (A) and working voltage VP (v), can decide flat type solar panels power generation power, thus designed solar panels, the design of the capacity of capacity and reference solar array working voltage (VP), determine the silicon cells quantity in series and in parallel.

Following is the specific design procedure of the solar panel array:

1. the load Consumption capacity in 24 hours: P

P = H/V V-load rated supply

2. Selected sunshine hours every day T (H).

3. Calculation solar arrays work current.

IP = P (1 + Q) / T

Q-at the surplus coefficient of rain Q = 0.21 ~ 1.00

4. Sure battery charging pressure VF float.

Cadmium nickel (guide) and lead (CS) battery charging pressure were floating monomer 1.4 ~ 1.6 V and 2.2 V.

5. Solar cell temperature compensation voltage VT.

N = 2.1/430 (T-25) VF

6. Calculation solar array working voltage VP.

VP = VF + DVD + n One DVD = 0.5 ~ 0.7 VF is about equal to the

7. Solar array output power reference (flat type solar panels).

Reference = IP x UP

8. According to the VP, reference in silicon plate series, determine the combination form standard 
specifications of series KuaiShu and and LianZu number.

The battery capacity calculation

The capacity of the battery by the following factors:

1. Battery alone work days. In the special climate condition, the battery to allow discharge battery left of 
the rated capacity of the normal capacity by 20%.

2. Put the battery power every day. For day load stable and demand is not high occasions, th discharge cycle .can be restricted in depth with battery capacity rated capacity of 80%.

3. The battery to have enough capacity to ensure that won"t because of charging caused by water loss. 
Generally in the battery capacity, choose as long as battery capacity than solar panels 25 times of peak 
current, the battery in charge will not cause water loss.

4. The battery power, with their own missed the battery life of the growth and the battery, the rise of 
temperature will increase life.low self-discharge rate. For new battery life. low self-discharge rate is less than 5% of capacity, usually but to old quality is bad of the battery, self-discharge can earn up to a 10% to 15% a month.In the fullness of telemetry system, the length of the continuous cloudy/rainy days determines the capacity of the battery. By remote sensing equipment in the continuous cloudy/rainy days consumed in energy (Ann hours plus 20% factor, plus 10% battery self-discharge will be to put hours) calculated the capacity of the battery.

Solar charge controller and solar power inverter is an essential part of the solar system.

Solar Charge Controller applies in solar photovoltaic systems, which coordinates the working of solar panels, batteries and loads. It adds some protection functions, so that the entire system can be in efficient and safe operation.