Tensión CC del sistema
La tensión del sistema de CC elegida para el sistema afectará el tamaño y la selección de todos los demás componentes del sistema. Los sistemas FV autónomos generalmente se construyen con varias tensiones estándares (12 V, 24 V o 48 V), ya que todos los componentes del sistema deben estar clasificados para funcionar con la misma tensión. Cada tensión tiene diferentes ventajas y desventajas que lo hacen apropiado para diferentes tamaños y tipos de sistemas. Una limitación que es común a todos los sistemas de almacenamiento de energía de plomo-ácido es que no se recomienda incorporar más de 3 cadenas paralelas de baterías, ya que puede crear problemas durante el proceso de carga; consulte Cableado de baterías. Esta restricción a menudo determina la tensión del sistema.
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Sistema de 12 V
Ideal for smaller systems and direct current (DC) only systems. Commonly uesd with systems that have a PV source with a power rating below 700 W. Not recommended for use with inverters larger than 800 W due to current/wire sizing issues.
Advantages
- 12 V deep-cycle lead acid batteries are widely available.
- Wide selection of available components (inverters, charge controllers).
- Wide selection of 12 V DC lighting and DC appliances.
Disadvantages
- Use with a PWM charge controller requires 12 V (36-cell) nomimal modules. 36-cell modules typically cost more per-watt than more common modules like 60-cell and 72-cell modules.
- Operating loads with high power ratings at 12 V can require significant amounts of current. This can create issues for wire sizing and overcurrent protection device sizing.
- Operating a system at 12 V can create voltage drop, which can require large wire sizes to ensure the system performs properly.
24 V system
Commonly used with systems that have a PV source with a power rating above 150 W and below 1500 W. Not recommended for use with inverters larger than 1200 W due to current/wire sizing issues.
Advantages
- A PWM charge controller permits the use of cheaper 72-cell modules.
- Wide selection of available components (inverters, charge controllers).
- Larger battery bank with fewer parallel strings.
- Less current required to power loads with high power ratings. This creates less issues for Wire, overcurrent protection, and disconnect sizing and selection
- Less voltage drop issues compared to a 12 V system.
Disadvantages
- There are significantly fewer lighting and DC appliance options. that operate at 24 V. A DC-DC converter can be incorporated into the system to power 12 V loads if necessary.
48 V system
Commonly used for any systems that has a PV source with a power rating above 1200 W or an inverter larger than 1200 W.
Advantages
- Allows the highest capacity battery bank with minimal parallel strings.
- Minimal current required to power loads with high power ratings. This minimizes issues for wire sizing and overcurrent protection device sizing.
- Less voltage drop issues compared to 12 V or 24 V systems.
Disadvantages
- Very limited lighting and DC appliance options that operate at 48 V. A Special:MyLanguage/DC-DC converter can be incorporated into the system to power 12 V loads if necessary.
- Smaller selection of available components (inverters, charge controllers).
