Efectos negativos de la caída de tensión del cable

Limitar la resistencia de un circuito evita caídas de tensión pero, ¿qué efectos tiene en el sistema si ocurren?
21 de febrero de 2020 por
Efectos negativos de la caída de tensión del cable
Techno Sun, SLU, Hugo Rodrigo Zapata :

Effects of a voltage drop on the system

Some of the effects of a strong voltage drop in the system are:

• Energy is lost and the system is less efficient. Batteries discharge faster.

• It will increase the system current. This may cause the DC fuses to blow..

• The presence of high currents in the system can cause premature overloading of the inverter..

• If a voltage drop occurs during charging, the batteries will not be fully charged.

• The inverter receives a lower battery voltage. This can trigger low voltage alarms.

• The battery cables become hot. This can cause the insulation on the cables to melt or cause damage to the cable conduits or equipment that is part of the system. In extreme cases, heating of the cables can cause a fire.

• All devices connected to the system will have a shorter life due to DC ripple.

How to avoid voltage drops?

• Use cables of the shortest possible length.

• Use cables with sufficient thickness

• Tighten the connections (but not too tight, follow the torque recommendations in the manual).

• Check that the contacts are clean and free of corrosion.

• Use quality cable lugs and mount them with the appropriate tool (crimper).

• Use quality battery isolation switches.

• Limit the number of connections of each cable run.

• Use distribution points or DC busbars.

• Respect the legislation on connections.

It is advisable to measure the voltage drop of the system once an electrical installation with batteries has been completed. Remember that voltage drops usually occur in high current situations. The voltage drop is higher when the current increases. This occurs when an inverter has a maximum load connected or when the battery charger is charging at full current.

This is how the voltage drop is measured, for example, in a system with an inverter:

• Load the inverter at full power.

• Measure the voltage on the negative cable between the inverter connection and the battery pole.

• Do the same with the positive cable.

If the battery and inverter are too far apart, or if the battery is in another room:

• Load the inverter at full power.

• Measure the voltage of the DC connections inside the inverter.

• Measure the voltage at the battery poles.

• Compare the readings. The difference between them is the voltage drop.

Source: Wiring Unlimited de Victron Energy