UPS batteries charging rates

Basically charging rates for UPS batteries depend on type of batteries cell such as Lead-acid (Pb) or Nickel Cadmium (NiCd).This two types of batteries cell have a different method to charging up.

For Lead-acid (Pb) cells is used a ‘constant voltage’ method.It mean where the current varies as the state of charge changes.Different method for Nickel Cadmium (NiCd) cells,it  is used ‘constant current’ where the cell voltage varies as the state of charge changes.

When we try to charging batteries  from  Lead-acid (Pb) cells type,the basic process are from a constant voltage source the charging current starts high and slowly decreases to a constant value when the cells become fully charged.The constancy of the current is an approximate indication that the cells are fully charged. read more

UPS battery charger

When indicator for batteries level shown a it  need to recharge,We must charge the batteries to ensure it in full capacity and can operate during power failure.But for UPS batteries charger it typically build in the UPS system.

Now in market,it have several battery charger technology for AC and DC UPS.Basically it similar with car battery charger.The method and technique similar with conventional charger.

Manufacture always improved and made R&D to created battery charger more efficient,safety and durability for user.They design with electronic device for more accurate and faster charging system. The advanced technology usually design for batteries charger included with several items below :- read more

Battery for UPS

For uninterrupted power supply ( UPS ),the important component is a battery unit for UPS.The battery are used to store DC energy which is later used to supply a block of energy to a load,often in the form of a high current for a short time example to charge mechanism springs in switch gear,fire fighting system,emergency lighting, emergency instrumentation power for control panels and control devices and starter motors on engines generator.

Battery for UPS  must in good condition and well maintain to ensure it can operating in full capacity when it needed.If the battery failure during interruption of power supply,it can cause serious damage and high cost for operation recovery.

Types of battery

Normally for industry used applications are invariable of two kinds of battery,It have a advantage and disadvantage depend on our application :

1) Lead-acid (Pb).

2) Nickel-cadmium (NiCd).

A battery consists of a number of cells connected in series. The series connection is necessary to create sufficient load voltage. Each cell has a low voltage which is peculiar to the type of cell and independent of the current and rating of the cell. The cell voltages are shown in Table 17.1.


How to recharge the batteries for UPS?

The maximum cell voltages during charging should not exceed 2.7 volts per cell for Pb cells and 1.85 volts per cell for NiCd cells.Suppose a nominal voltage of 110 DC is required then at least 54 Pb cells or 89 NiCd cells would be required.The size of a battery is defined as its ampere-hour capacity, since capacity is related to charge (Q) which equals current (I ) × time (T ).


If there is a total failure from the main supply then it will usually be necessary to maintain the continuous current for 4 hours so that the state of the plant will be known during the failure. During this time it would be expected that the main supply would be restored.

Hence the 4 hours can be used as the operating cycle of the battery in the event that the charger is unable to supply current.

For the battery storage and compartment it may be installed in several ways.Example it can install integral with the charger, in a separate cubicle or on open racks.

The choice usually depends upon the physical size of the complete battery.If we plan to used a large battery,it are more suited to an open rack installation.

Benefits of power factor correction

Now around the world,hot topic is about energy saving and energy efficiency.The main item very popular for discussion is how to reduce electricity bills.

In industrial sector,the first step to reduce electricity bills is a power factor correction.This post i explain about the benefits of power factor correction for energy saving and efficiency.It also common practice for industrial.

I already discuss in my last post about power factor correction and capacitor sizing for power factor correction.If you understand the concept and how to calculated the capacitor sizing,you also can do it your self for power factor improvement. read more

Overload relay setting and calculation

Overload relay is the one of important device for motor control.It can prevent our motor from overheat or winding burning due overload of ampere.

We need to setting the value of overload relay properly depend on our application and motor full load ampere.If we setting low from FLA,it can cause motor trip c0ntinues and process not running smoothly.

But if we setting to high from FLA,the overload relay cannot protect the motor if overload happen.It can cause the motor failure or winding burns.So we must calculated and get a right setting for the overload relay. read more

Types of motor overload relay

A motor overload relay is an electro-mechanical relay that is operated by heat developed in the relay.When the level of current in a circuit reaches a preset value, the increased temperature opens a set of contacts.

Overload relay should install in our motor starter application for extra protection.Overload relay can avoid serious damage for electric motor when overload happen to our system with proper setting.

The increased temperature opens the contacts through a bimetallic strip or by melting an alloy that activates a mechanism that opens the contacts depend on our setting for overload relay.This time i explain detail about common types of overload relay for motor control. read more

Testing electrical & electronic component

To be a good troubleshooter,we must know how to testing electrical and electronic components.Several components are common used in electrical and electronic device or equipment.This technique is a common essential for the troubleshooter.

The important measuring device that we should have to perform a testing task is a ” Multimeter”.This meter is used to measure continuity or resistance in components.

If you not understand what is this,please read my last post title ” what is multimeter” and ” how to use multimeter?”.I explain detail in my video about multimeter. Read more