Views: 576 Author: RJ Publish Time: 2019-11-13 Origin: RJ
Lead acid batteries are all 12V batteries, that is, they are made of six nominal 2V battery units in series, which has a history of more than 100 years. At present, the voltage of emerging lithium batteries is 48V, so which is better for 12V or 48V?
Electric power = voltage * current. Under certain electric power, the voltage and current are inversely proportional. The higher the voltage is, the lower the current is. According to Joule's law, when the current passes through the conductor, it will generate heat and lose part of the electric power, and the power lost by heating is in a positive proportion to the product of the prismatic of the current and the resistance. This shows that the larger the current is, the more heat will be lost when the power is turned on, and the lower the efficiency of using electric energy will be. This is also the fundamental reason why the power supply system should use high-voltage power supply. The higher the voltage is, the lower the current will be, and the less power the current will lose due to heating.
Through this, it is easy to understand that the efficiency of 48 V power supply system is higher than that of 24 V power supply system, and that of 24 V power supply system is higher than that of 12 V power supply system.
The advantages of 48V battery for RV are as follows:
1 line loss and heat analysis:
48V RV circuit has small current, small loss and less heat
2. Charging and line safety analysis:
48V RV circuit has higher charging efficiency and safety
3. Discharge and line safety analysis:
48V RV circuit has higher discharge efficiency and can safely use high-power electrical appliances
4 Analysis of key electrical equipment:
48V RV circuit can better use high-power electrical appliances
To sum up, the circuit system of RV is upgraded to 48V system, with obvious advantages. No matter in the overall efficiency, safety, reliability and life of the system are far higher than that of 12V system, so, just like pure electric vehicle, 48V system is the general trend of RV circuit.
Advantages of 48V circuit system:
1. Lower than 60V safety voltage, no additional voltage protection is required, and the cost is lower than that of high-voltage hybrid system;
2. Compared with 12V system, the working current is only 1 / 4 at the same power, and the loss is only 1 / 16 of 12V system.
3. With the help of the electric power of BSG / ISG, the volume of the engine can be further reduced, and then the emissions can be reduced.
4. The high load accessories on the traditional engine can be electrified, such as air conditioning compressor, cooling water pump, vacuum pump, etc., to reduce the load of the engine, even when the engine is off, these equipment can work;
5. Raising the working voltage of the vehicle electrical appliances to 48V can further reduce the loss and the outer diameter of the harness
6. It can support higher power on-board equipment.