Chhabi Electricals Private Limited


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2 of the 5 Best Schemes of Battery Charger

(Silicon Controlled Rectifier Equipment)

1st Scheme
(Float cum Boost charger – Single Battery – Single load)

The Battery Charging equipment comprises Float cum Boost charger.

Float cum Boost charger has two modes of operation i) Constant Voltage Float
Mode, ii) Constant Voltage / Current Boost Mode (as applicable as per the battery type).

Normally in float mode, charger will supply the trickle charging current required for the batteries and will also feed the DC continuous load as required. During this time, the charger and the battery are across the DC load terminals. If charger fails, the battery will supply the load through DC contactor.

During an emergency when AC power fails, the battery supplies the load and discharges to certain extent depending upon duration of emergency. When AC power is restore, the battery needs to be boost charged for which operate Float cum Boost charger in its boost mode.

When there is a power failure, the battery readily meets the DC loads. When the power resumes, the battery has to be recharged for which operate the Float cum Boost charger in Boost mode. During this period of boost charging, the DC contactor will gets open & the load will be supplied through Battery Tap diodes or Voltage dropping device as per logic provided in charger. Thus, higher voltage during boost charging will not appear across the load.

scheme-1


2nd Scheme
(Float and Float cum Boost charger – Single Battery – Single load)

The Battery Charging equipment comprises Float charger & Float cum Boost charger. Float charger has only Constant Voltage mode. It is capable to supply trickle charging current to battery as well as supply the station load.

Float cum Boost charger has two modes of operation i) Constant Voltage Float Mode, ii) Constant Voltage / Current Boost Mode (as applicable as per the battery type).

Normally, float charger will supply the trickle charging current required for the batteries and will also feed the DC continuous load as required. During this time, the float charger and the battery are across the DC load terminals. If float charger fails, the float cum boost charger will operate in float mode either Manually or Automatically depending upon the circuitry logic provided in charger as per customer specification.

During an emergency when AC power fails, the battery supplies the load and discharges to certain extent depending upon duration of emergency. When AC power is restore, the battery needs to be boost charged for which operate Float cum Boost charger in its boost mode.

When there is a power failure, the battery readily meets the DC loads. When the power resumes, the battery has to be recharged for which operate the Float cum Boost charger in Boost mode. During this period of boost charging, the DC contactor will gets open & the load will be supplied through Battery Tap diodes or Voltage dropping device as per logic provided in charger. Thus, higher voltage during boost charging will not appear across the load.

scheme-2



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Types of Battery Charger and its Comparison

Type-I : Thyristor Based Battery Charger  

tbh-i

  • Long operational life more than 20 years.
  • Robust operation
  • Easy for troubleshooting

SCR Firing techniques

  • 6 Pulse
  • 12 Pulse
  • 24 Pulse

Advantages: 12 & 24 Pulse Chargers

  • Very low ripple factor
  • Minimized Harmonic Distortion
  • Improved Power Factor
  • Higher Efficiency 90%

Function Block Diagram

BLCDiag.png

chart-i

Type-II : SMPS Based Battery Charger:

mbh-i

  • Rectifier Efficiency better than 92%
  • Power Factor better than 0.90%
  • Compact – High Power Density
  • Wide AC input range
  • Output voltage suitable for all types of Batteries
  • Current Stabilization Accuracy less than 0.5%
  • Ripple less than 0.5%
  • Current sharing imbalance for rectifier less than 3%
  • Operate with wide frequency variation.

Comparison between Thyristor Based & SMPS Battery Charger :

compare-i


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3 of the 5 Best Schemes of Battery Charger

3rd Scheme
[Dual Float cum Boost charger – Single Battery – Single load]

The Battery Charging equipment consist of Dual Float cum Boost charger. In normal operating condition, Both the chargers will be in Float mode to supply station load & trickle charge the Battery, equally sharing the total load.
During an emergency when AC power fails, the battery supplies the load & it discharges to a certain extend depending upon duration of emergency. At this time, DC contactor will be in energized condition.
When AC power is restored, the Battery needs to be Boost charged. Under such condition, one charger shall be operated in Float mode to supply the station load & operate another charger in Boost mode for charging the battery. At this time, Battery positive bus & load positive bus will be separated by DC contactor and / or MCCB as applicable.

scheme-3


4th Scheme
[Dual Float cum Boost charger – Two Battery – Single load]

The Battery Charging equipment consist of Dual Float cum Boost charger. In normal operating condition, Both the chargers will be in Float mode to supply station load & trickle charge their respective Batteries, equally sharing the common load.
During an emergency when AC power fails, the both batteries supplies the load & it discharges to a certain extend depending upon duration of emergency. At this time, DC contactors will be in energized condition.
When AC power is restored, the Batteries needs to be Boost charged. Under such condition, one charger shall be operated in Float mode to supply the station load & another charger in Boost mode for charging the respective battery and vice – versa.

scheme-4


5th Scheme
[Dual Float cum Boost charger – Two Battery – Two load]

The Battery Charging equipment consist of Dual Float cum Boost charger with dual batteries & dual load. In normal operating condition, Both the chargers will be in Float mode to supply their respective load & trickle charge their respective Batteries.
During an emergency when AC power fails, the both batteries supplies the load & it discharges to a certain extend depending upon duration of emergency. At this time, DC contactors will be in energized condition.
When AC power is restored, the Batteries needs to be Boost charged. Under such condition, one charger shall be operated in Float mode to supply the both load & another charger in Boost mode for charging the respective battery and vice – versa.

scheme-5