Let's start with a few low-tech rumors:

1. Solar street lamps use 12V batteries with higher brightness than 3.2V lithium ion iron phosphate batteries

Now let me ask a common-sense question: Which one is brighter, a car headlight or a house headlight?

Car headlights generally 12V or 24V, home lights are 220V, very low technical knowledge tells us, brightness and voltage is not directly related.

2. The structure of 3.2V lithium iron phosphate battery is too simple

The 3.2V system is a bit cleaner than the 12V system, but that's not the point. As we all know, lithium iron to be connected in series to 12V in the four batteries to do internode protection and uniform flow balance, but this series of four batteries consistency requirements are very high, on each battery work temperature consistency requirements are higher this point solar lamps in the outdoors is difficult to ensure. Yes, you can do this with an expensive BMS for an indoor laptop or an outdoor electric car, but for a few hundred yuan solar lighting, even the price of the protector chip is not enough. In addition, iron lithium-ion batteries mostly use laddered batteries and so-called B products (A products have been more than three times the price of lead acid in recent years, is unlikely to be used in large numbers). Not to mention battery consistency.

Therefore, the simple structure of 3.2V without internode protection has been given an unprecedented opportunity. After 6 years of testing, the failure rate is even far lower than that of municipal electric street lamps. By the way, ternary lithium itself is product A, but most of its origin is important indoor products (notebook, charger, etc.), not suitable for outdoor.

Flammable and explosive itself can also be controlled (Samsung excepted), but only if there is enough BMS cost (Tesla), the light brothers obviously do not have this condition. Therefore, the photovoltaic street lamp fire explosion of the uniform 12V ternary lithium. A burned out lamp can be replaced. If the forest is lit, the manufacturer and the engineer will not simply lose money.

3, 3.2V iron phosphate lithium ion battery current is too large, will burn out the MOS and wires

This point of view is very funny, it is only less than 100 watts, the current high conductance MOS, IGBT technology is very expensive, the current of 50A is only a few yuan, not to mention the wire, a total of tens of centimeters of wire, you don't even have the courage to make a little thicker? I think it's the habitual thinking of cutting corners for a long time.

4, 3.2V iron phosphate lithium ion battery is not suitable for constant current intelligent control and maximum power point tracking

Before I rebut this, I'll give you a technical nous: The voltage fluctuations between the charge and discharge of the 3.2V lithium-ion iron phosphate battery are very small, and the release of significant capacity is concentrated between 2.9V and 3.3V, which falls squarely into the junction voltage range of the white LEDs -- a quantum entanglement designed by God. Even the use of full power to drive white LED will not exceed the maximum rated power of LED, so the PWM control is sufficient, and there is no need to add a high failure rate of constant current drive. Secondly, regarding intelligent control and maximum power point tracking (MPPT), I believe that these were designed to reduce the high cost of panels and batteries, but some people still feel that the PV story is not finished, the controller story is not finished, the inventory thinking. Subsidies for new energy have come to an end. Lithium-ion batteries and panels have become as cheap as they are today, not counting light poles, which cost 20 metres of cable, and each street lamp requires at least 50 metres of cable.

Using this underlying algorithm, if the solar panel goes below 30 RMB/Wh, the light tracking technology is useless. If it goes below 15 RMB/Wh, the MPPT (maximum power point tracking) is meaningless. Now it is below 2 RMB/Wh, the cable is useless and the state subsidy is completely unnecessary.

Instead of telling a story with MPPT just to sell the design, it's cheaper and more reliable to simply add panels. The same is true for intelligent control. Solar street lamps are mostly installed in backward areas. I do not believe that village electricians run dozens of miles every day to adjust the time of light control with their mobile phones on mountain roads.

All the solar street lamps in the picture choose 3.2V lithium ion iron phosphate battery as the battery!

Here I introduce a single section of lithium iron phosphate battery 3.2V advantages:

1, the battery has no balance problem, the life can be more than 15 years

Because iron phosphate lithium ion battery is all for the production of electric vehicles manufacturers are almost all motherboard listed companies, outdoor environment 3C discharge intensity, from the design of the root is red. Turn to the street lamp, only 0.1-0.3C charging intensity, the car used for 8 years, solar street lamp used for 15 years without a problem. I often give examples such as Liu Xiang is too old to do the 100-meter hurdles, let him practice slow walking can serve until he is 80 years old.

2, the controller and the lamp bead are directly attached together, the reliability is greatly improved, the installer only needs to plug in the DC plug.

3, weak light power generation is much better. Anyone can do a good job of photovoltaic street lamps in sunny days. The key is the precious power generation of weak light in rainy days. The reason is very simple, the photovoltaic effect depends on the intensity of light to appear the electromotive force (voltage), generally speaking, when driving uphill, do you hang first gear or hang four gear? 3.2V will not cut off low current charging in cloudy and rainy days.

4, LiFePO4 according to the molecular formula, iron lithium ion battery has no heavy metals, no scarce resources, will become a cheap and clean energy storage battery. Cobalt is so scarce in ternary lithium that cobaltates have tripled in the past year alone.

There are several advantages, a period of time to say it again peer share.

Finally, many people will ask that every coin has its two sides, so I would like to mention a few disadvantages of 3.2V iron phosphate lithium ion battery.

The wiring does need to be thick, and we even use military-grade plugs.

(2) the supply chain management and production equipment requirements are very high, for example, iron lithium manufacturers generally start from the main board listed companies, there are capital and quantity threshold; For another example, full parallel connection has high requirements for LED suppliers. We only use Riya Chemical, the world's first, and the batch tolerance is less than one in a million.

(3) Lead acid manufacturers, controller manufacturers, three lithium manufacturers have subversive damage, and the traditional government bidding documents are generally written by them.

(4) The above points, summed up in a word, the pursuit of low failure rate, long life and high cost performance is the real pain point of the photovoltaic street lamp industry for many years. The light of the two harms is the right choice. We use six years, tens of millions of lights to practice, prove and believe that the choice of 3.2V iron phosphate lithium ion battery is the future.

Currently, more and more competitors are choosing the technology path of 3.2V iron phosphate lithium-ion batteries. In a few days, we will launch the high-brightness solar street lamp with the Riya light source of 150 watts and above 30,000 lumens, which will become the brightest photovoltaic street lamp in a single lamp holder with a life of 15 years.