Is the 100w better than the 20w one? Why is the 100W selling at a lower price than the 20W one?
In the market, the solar light power marked at no generic standard creates so much confusion for people who are trying to buy solar lights online.
What’s worst is that most people can’t test the real power of solar lights without professional electrical knowledge of the solar lights. They can’t tell the solar lights they buy are with real power as marked or not.
In this article, we focus on solar light power and explain the solar light system design principle.
First of all, we need to clarify that the solar lights we are going to explain are for home users only, we only focus on residential use solar lights, we are not talking about street project solar lights or industrial use solar lights.
1. Reasonable configuration among the solar lights key parameters
When a solar lights manufacturer designs a solar light, we will consider 3 main factors of the solar light:
Solar Panel Power（Ps）
For civil solar lights, most of the solar panel voltage is 6V, battery voltage is 3.2V, the charging and discharging mode is PWM or constant voltage. (90% of the solar lights are designed like this)
Battery capacity Bc = Solar panel power Ps * coefficient N
Per our experience, N=0.75~0.85, let’s take N=0.8
For example, if a solar panel is 30W/6V, the reasonable battery capacity shall be 30*0.8=24AH. Theoretically, if the battery capacity is 30AH, there will be 6AH (30-24=6) capacity wasted.
Of course considering the charging characteristic of the battery, the higher battery capacity, the higher charging efficiency. However we can not only focus on the solar system efficiency, we need to consider the production cost at the same time.
2. How to know the real power of solar light?
As mentioned above, many shops are selling the same solar light in different power.
Like a 10W solar street light, some shops will sell it in 200w only because it has 200pcs LED, but in fact, each led is not working at 1W, it doesn’t need LEDs chips in that many pcs for only 10W.
So how can people know the real power of solar light?
Let’s pass the complicated calculation process and tell the conclusion directly.
Solar light real power = Solar Panel Power Ps * coefficient N
N=0.4~0.6, usually we take N=0.5
For example, a solar light with a solar panel 30W, no matter how many led chips it built inside, no matter how high the battery capacity is, the real power of the lamp shall be around P=30w*0.5=15w.
If the solar light manufacturer designs the working power of the solar light lower than 15W, then the lasting time of the solar light will be longer. If the solar light manufacturer designs the working power of the solar light higher than 15W, then the lasting time of the solar light will be shorter.
No matter how the solar light manufacturer design the solar light, the real power of the solar light can not exceed the solar panel power of 30W.
After having a very clear understanding of these two points above, now you can be an expert while browsing the solar lights shops online.
You no longer focus on the solar light power marked by the solar lights supplier only, you are able to tell the reasonable configuration among the solar lights key parameters, and you are able to tell the real power by studying the solar panel power.
If not, try to read this article again. Welcome to contact us for further discussion about all solar lights knowledge.