Using PhotoMOS Relays For Battery Monitoring in UPS Applications

April 19, 2012
By Anonymous

PhotoMOS Relays And Battery Monitoring

PhotoMOS Relays can be used to monitor battery charge, which in turn can extend battery life and avoid hazardous situations. Battery monitoring is highly useful for Uninterruptible Power Supply (UPS) applications because they need to be reliable. The UPS is only as reliable as the batteries are healthy and able to provide proper back up power when needed.

PhotoMOS Relays As Isolation Barriers

Isolation is the resistance to signal leakage, which may occur when the circuit between a contact and terminal is open. The amount of leakage is represented in decibels, and is a very important requirement in UPS applications. When the isolation value is larger, the leakage that occurs in the UPS system is smaller. PhotoMOS Relays provide an excellent isolation barrier. Shown below is a Capacitor switch circuit. Figure 1 schematically explains how a PhotoMOS is used to monitor the battery.


                                                   Figure 1: Capacitor Switch Circuit

PhotoMOS # 1 Relay is turned on to charge the Capacitor. The signal that charged the Capacitor will discharge into PhotoMOS #2 once it’s turned on. Then, the signal will be amplified and measured, which helps to monitor and record battery health at any given time. When the battery is getting low on charge, the output voltage will be low, indicating that the PhotoMOS needs to charge the Capacitor, which in turn refills the battery. 

Benefits Of Using PhotoMOS For Battery Monitoring:

  1. Longer Life
  2. Higher Reliability
  3. Enhanced Safety
  4. Reduced Maintenance Costs
  5. More Efficient Battery Management
  6. Reduced Risk and Losses for Businesses
  7. Time Savings

Panasonic has a wide variety of PhotoMOS Relays that can be used in UPS and various other applications.