1. The solar street light uses a 12V battery with higher brightness than a 3.2V lithium iron phosphate battery
Now I ask a very common-sense question: Which one is brighter than the headlights used in the car and the lights at home?
Car headlights are generally 12V or 24V, and home lighting is 220V. Very low-level technical common sense tells us that brightness and voltage are not directly related.
2. The structure of 3.2V lithium iron phosphate battery is too simple
This is not wrong, 3.2V is simpler than the 12V system, the key point is not here. We all know that if iron-lithium is to be connected in series to 12V, inter-node protection and uniform current balance must be performed between four batteries. However, this requires high consistency for the four batteries connected in series, and the temperature consistency of each battery when working is required. The requirements are higher - this is difficult for solar lights to guarantee outdoors. Yes, if it's a laptop for indoor use or an outdoor electric car, you can use an expensive BMS system to do this, but for a solar light fixture of a few hundred dollars, it's not even enough for the price of a protector chip. In addition, most of the iron-lithium batteries use cascade utilization batteries and so-called B products (the price of A product has been more than three times that of lead-acid in recent years, and it is impossible to be widely used). Not to mention battery consistency.
Therefore, 3.2V, which has a simple structure and does not require inter-node protection, has gained unprecedented opportunities. After 6 years of testing, the failure rate is even far lower than that of the city circuit lights. By the way, there is nothing wrong with ternary lithium itself being an A product, but most of its origins are mainly indoor products (notebooks, power banks, etc.), which are not suitable for outdoor use.
Inflammable and explosive itself can also be controlled (Samsung exception), but the condition is that there needs to be enough BMS cost (Tesla), the lighting brothers obviously do not have this condition. Therefore, the photovoltaic street lights are all 12V ternary lithium that catches fire and explodes. A burnt out lamp can be replaced with a new one. If the forest is lit, manufacturers and engineers will not lose money.
3. The current of the 3.2V lithium iron phosphate battery is too large, which will burn out the MOS and wires
This point of view is very funny, the mere less than 100 watts, and the current high-conduction MOS and IGBT technology are already very expensive. At a current of 50A, it only costs a few yuan, not to mention the wires, which are a total of tens of centimeters long. Line, you don't even have the courage to bold it? I think it is the inertial thinking of cutting corners for a long time.
4. 3.2V lithium iron phosphate battery is not suitable for constant current intelligent control and maximum power point tracking
Before refuting this point of view, let me talk about a technical common sense: the voltage fluctuation between the charging and discharging of a 3.2V lithium iron phosphate battery is very small, and the release of the main capacity is concentrated between 2.9V-3.3V, which just falls on the white LED. In the range of junction voltage - this is "quantum entanglement" designed by God. Even if the white LED is driven with full power, it will not exceed the maximum rated power of the LED, so PWM control is sufficient, and there is no need to add a constant current drive with a high failure rate. Secondly, regarding intelligent control and maximum power point tracking (MPPT), I think these were designed to reduce the high cost of panels and batteries, but some people still feel that the story of photovoltaics is not finished, and the story of the controller Not finished yet, stock thinking. New energy subsidies have basically stopped, and lithium batteries and battery panels are already cheap to today's level—not counting light poles, that is, the price of laying 20 meters of cable, and each street light requires at least 50 meters of cable.
With this underlying algorithm, if the solar panel is lower than 30 yuan/Wh, the light tracking technology is useless, and if it is lower than 15 yuan/Wh, MPPT (maximum power point tracking) is meaningless. Now it is lower than 2 yuan/W. Cables are dead, and state subsidies are completely unnecessary.
