UPS Inverter Faqs

Inverter Questions

In order to maximize the output power (AC power) that an inverter can generate from a given amount of input power (DC power), it is important to select an inverter with the following characteristics:

High efficiency

Low standby losses – These losses are due to the power consumed by the inverter when it is on but no loads are running. This is the case in most residential situations, so it is important to select an inverter where these losses are a minimum.

High surge capacity – Many household and office appliances, especially those with motors consume high power when they are switched on. If the inverter does not have sufficient surge capacity to support these loads then the inverter will shut down and could potentially get damaged as well.

Low harmonic distortion – Harmonics can lead to performance problems in motors and sensitive electronics and also impact the useful lives of these equipments, hence it is always advisable to minimize the harmonic distortion caused by the output power produced by inverters. As mentioned in the table above, sine wave inverters have low harmonic distortion while square wave inverters have the highest harmonic distortion
My Requirements Suggested Inverter Model's
For 1 BHK house  600-700 VA
For 2 BHK house 850-1100 VA
For 3 BHK house 1500-2000 VA
For Office with 2 Computers 1500-2000 VA (Sinewave)
For Office with 1 Computer 850-1100 VA


• Usually You need additional 20% of the below Load.
• for eg: for your Fan=80-100va, Tube light=40-60va, TV 21"=250-300va, computer=300va, etc all sumup and add 20% extra, you will derive the capacity required for the Inverter or You can try our Online Wizard for UPS/Inverter/Battery Selector
The efficiency of an inverter determines the amount of AC output power it generates for a given input of DC power. This usually ranges from 85% to 95%, with 90% being about average.

When running such things as motors, the efficiency actually has two parts to it – the efficiency of the inverter, and the efficiency of the waveform. Waveform efficiency means that most motors and many electronic appliances run better and use less power with a sine wave. Typically, an electric motor (such as a pump or refrigerator) will use from 15% to 20% more power with a modified sine wave than with a true sine wave. Thus when choosing an inverter based on efficiency, you should also consider the type of loads being powered to determine true system efficiency.
Inverters are classified into different types based on the waveform of the output AC power they generate. The dominant waveforms generated by commercially available inverters are – square wave, modified sine wave (also known as quasi-sine wave) and sine wave (also known as pure sine wave)

Sine wave is the most superior waveform (as it matches the waveform of the AC power that we get from the utility grid) and inverters that generate this waveform are typically more expensive while square wave inverters require minimum circuitry and hence are the cheapest. With the prices of sine wave and modified sine wave inverters coming down and the increasing need of providing back-up power and protection to sophisticated electronic devices square wave inverters are gradually being phased out.

Inverter waveform

Square wave

Modified sine wave

Sine wave

Loads suitable for

Lights and fans only Lights, fans, Personal Computers, TVs (there might be electrical noise in case of some models, check the specific inverter model), other household appliances All kinds of loads including sensitive electronics

Harmonics/Audible noise

High Medium Low


Low Medium High


Sine wave inverters:

The major advantage of a sine wave inverter is that it ensures trouble-free and efficient operation of all electrical and electronic equipments. Please note:

  • Certain appliances like sensitive medical equipment, audio/video electronics, household appliances such as variable speed drills, bread makers, light dimmers and battery chargers require waveforms with low harmonic distortion and should be connected to only sine wave inverters.
  • Many inductive loads, such as appliances containing motors also produce full output only when operated with true sine wave power.
  • Sine wave inverters also have a higher surge power tolerance and are able to cater to the higher surge current drawn by inductive loads during start-up.

Modified sine wave inverters:

These inverters provide a good value proposition as while not as expensive as sine wave inverters, they still are compatible with a broad range of electrical gadgets used at home or office such as TV, computers, printers etc. Please note:

  • When modified sine wave inverters are used to power inductive loads, such as appliances having motors, solenoids, compressors, pumps or relays, the loads tend to consume about 10-20% more power than when powered with true sine wave power.
  • Appliances with electronic timers and/or digital clocks will often not operate accurately due to the noise in a modified sine wave compared to a pure sine wave.

Square wave inverters:

These inverters are the cheapest and are typically suitable for running lights, fans and other devices that are not impacted by the harmonics present in this waveform. It is important to not connect square wave inverters to sensitive electronic appliances as they might cause irreparable damage to them.
Nothing in particular. All you need to be careful of is the type of equipment and appliances you want to run. For sensitive ones, a Sine Wave UPS with a short transfer time is recommended. If you wish to run only fans and tube lights, a square wave inverter/home UPS will suffice. The backup time will depend on the capacity of the battery.

Load Questions

Determine the total load (in watts) of the equipment you want to protect. Add 10-20 per cent to allow for future growth and then select the appropriate UPS capacity based on the minimum amount of runtime you need.
There are three major types of loads: resistive load (lamp's); capacitive load (computer) & inductive load (motor).

All these types of load can be used with pure sine wave inverter; however, only resistive and capacitive loads can be used with modified sine wave inverter or Pure sinewave. For Motors, we recommend Pure sinewave inverter or UPS
For 3 kva Sine wave inverter it supports up to 1 ton AC and for 5 KVA Inverter it supports up to 1.5 TON AC.
There are three major types of loads: resistive load (lamp's); capacitive load (computer) & inductive load (motor). typically inductive loads incorporating a motor inside which would require true sine wave UPS/Inverter. Otherwise, the motor in these units would easily overheat, give out a humming noise and eventually would get damaged if operated continuously! Motor might get 3-5 times higher than steady value. It is very difficult to calculate how big UPS should you choose using the rated power of refrigerator. The motor Pulling water up from great depth would also make pump's working more difficult and it make pump's working more difficult and it would take higher start-up current! Refer to Higher KVA UPS
Powerwale does not recommend to connect Laser printer to any of the Home UPS, you should use only inkjet printer for Home UPS, as the load of Laser printer is heavy

Laser Printer uses the heated rollers, and it will discharge the batteries very fast. Ensure that you go for Higher KVA UPS and Size the UPS for starting current Capacity

In short you should avoid connecting Home UPS to the Laserprinter, as it requires Higher KVA UPS (3 KVA above) Higher KVA UPS

Inverter Battery Questions

Powerwale is India’s largest marketplace for solar & power solutions. We help you make an assured, reliable purchase in the following ways

We help you select the Right Product : For power back-up, buy either pre-engineered inverter and battery packages based on your requirement or explore a solar power system for long-term savings in your electricity bill.

We carry only Genuine, Reliable products: We provide you the widest choice and carry genuine products from all leading manufacturers in India.

Make a Trusted purchase from Verified Sellers: Powerwale carries listings from only verified Sellers or Manufacturers. We provide comprehensive ratings on service & delivery for each seller offering you the flexibility to make a purchase of your choice.

We are a One-stop Solution: All our sellers offer you free delivery and installation and optional AC-side wiring at a nominal extra cost. We also offer an exchange discount if you would like to replace your old batteries with new batteries.
• Usually for Flat plate battery average life is 2-4 years and for Tubular 3-5 years and all depends on brand, and other many factors, including your battery maintenance. But in normal condition, if your battery got bulged, getting heated, taking more distilled water, getting more acid smell or battery leakeage, then you should replace your battery immediately whether it's giving proper backup or not. • If your battery is providing less backup and battery life time is over!, then you should replace with the new battery
• Yes You can, but it should be a new battery with the in same capacity, same brand, same model and it should be connected to parallel to the another battery . But if you add to the existing battery, then your existing may getting over heated and you will not get full life.
The choice of the appropriate battery depends on the following factors:
Desired back-up duration
Average operating temperature range
Space availability
Environmental factors
Topping up requirements

UPS that come with internal batteries typically use VRLA (Valve Regulated lead Acid) batteries which are also known as Sealed Maintenance Free (SMF) batteries.

While connecting external batteries to Inverters any of the different lead acid batteries can be connected with the popular ones being – Flooded batteries (Flat plate, Tubular, Tall Tubular) and SMF VRLA batteries (AGM and Gel).
Batteries are connected in both series and parallel configuration to increase the capacity of the battery bank thereby increasing the duration for which back-up power can be provided to the loads by the bank. However, while doing so, it is important to ensure that the DC voltage of the Inverter matches the voltage of the battery bank being connected to it to avoid any damage to the battery bank and to ensure appropriate charging of the battery bank by the Inverter.

When batteries are connected in series, the voltage of the battery bank goes up and is equal to sum of the voltages of the individual batteries. For e.g. if 2 nos. of 12V (150Ah) batteries are connected in series, the voltage of the battery bank will be 24V (= 12V+12V) and this battery bank can be charged by an inverter having a DC voltage rating of 24V. By connecting the individual batteries in series, the energy that can be stored in the battery bank increases to 3600Wh (=24V*150Ah).

When batteries are connected in parallel, the voltage of the battery bank is the same as the voltage of the individual batteries, while the capacity of the battery bank doubles. Please note that only batteries having the same voltage rating should be connected in parallel to ensure uniform charging/discharging of the batteries and to prevent damage to/maximize life of the individual batteries. For e.g. if 2 nos. of 12V (150Ah) batteries are connected in parallel, the voltage of the battery bank will be 12V and this battery bank can be charged by an inverter having a DC voltage rating of 12V. By connecting the individual batteries in parallel, the energy that can be stored in the battery bank increases to 3600Wh (=12V*(2*150)Ah).
Generally for 600-700VA Capacity Inverter, You need 100Ah to 135AH battery and for 850-1100VA you may required 150AH to 200AH battery, but all this depends on your backup time

Flat plate (Flooded)

Tubular (Flooded)


Suitable for

Low power applications Heavy duty applications, frequent power cuts UPS applications, back-up time less than 1hr


Low Medium High

Life expectancy

Around 3 yrs 4 to 5 years 3 to 5 years

Tolerance to depth of discharge

Suitable for discharges upto 80% of battery capacity Suitable for discharges upto 80% of battery capacity Suitable for discharges upto 50% of battery capacity

Cyclic operation life (Charge cycles at 80% Depth-of-Discharge)

500 – 800 cycles 1000– 1200 cycles 400 – 450 cycles

Charging time

Charges slowly compared to tubular batteries Faster charging Faster charging

Temperature performance

Inferior operation compared to tubular batteries Satisfactory operation at extreme temperatures (both high and low) Capacity reduces significantly at higher temperatures

Electrolyte top-up frequency

Frequent water top up required Less frequent top up No top up required

Space requirement

High Medium Low

Battery placement

Fixed Fixed Can be placed in any orientation

Battery Emissions

High, proper ventilation required Lower emissions compared to flat plate, proper ventilation required No battery emissions
Purchase a reputed brand with a Toll Free support No, Look for higher Deeper Discharge Cycles, Powerwale, Prefer Exide Brand and it has been dealing since 40 years
We suggest you to buy Exide InvaTubular IT500
The battery configuration for different Inverter/UPS models can be classified as below:

Internal batteries only – In this case the batteries are provided internally and the UPS provides different runtimes depending upon the load connected to it.

Internal batteries with extendable runtime option – In certain models, additional batteries can be connected externally that together with the internal battery increases the UPS runtime. The option to connect additional batteries externally is not available with all models and you need to check the specifications of the specific model to ascertain this.

External batteries only – In these models, the batteries can only be connected externally.
Battery capacity is normally defined in Ah (Ampere-hour) and represents the maximum amount of energy that can be extracted from the battery under certain specified conditions. However, the actual battery capacity during operation can vary significantly from the nominal “rated” capacity as actual capacity depends on the age, rate at which energy is being drawn from the battery, historical usage pattern (charging, discharging cycles followed) and temperature.

Lead acid battery capacity for Inverter/UPS applications is normally rated at a 20hr draw and is specified as C20 capacity of the battery. For e.g. C20 capacity of 100Ah means that the battery is capable of providing 5Amps of current when discharged by a load over 20hrs (5A*20h = 100Ah) under standard temperature conditions. This battery can be discharged at a faster rate (i.e. the load could draw a higher current from the battery, say 10A) but this ends up reducing the total energy (Ah) that can be extracted from the battery.

The capacity to which the lead acid battery is discharged before it is charged again (known as depth of discharge) also influences battery capacity and its life (number of charge/discharge cycles it can provide). The recommended depth of discharge for lead acid batteries should be less than 80%.
• Pls Clean your terminals may be if it is rusted, replace battery terminals if need and tigntened the wire legs properly.
• Pour distilled water in all battery cells if battery is dry or distilled water is less
• Battery is over heat (check the battery gravity, it should not be more 1240 in each cell)
• Inverter/UPS charging indicators stops blinking (Looks like battery problem, Pls purchase a new battery)
• Heavy load is being used like geyser, microowave, fridge, etc) Remove unnecessary load from the inverter
• SMF means it is sealed maintenance free battery, does not requires any distilled watter topping!! and it does not omit any hazardous acid fumes, this should be kept under 27 Degrees Room temperature
• Gel Tubular will give more life compare to SMF batteries and features both are same, but it can withstand in higher temperature as well!
• Lead acid battery requires maintenance like topping up distilled water, you may get Acid Smell, and it is old Traditional battery. If you maintain, it will give you good life, if not this batteries, will have very less life
The capacity of the battery that should be connected to an Inverter depends on the charging current the Inverter can provide as this determines whether the battery gets charged fully in a reasonable amount of time without getting damaged. Usually the battery capacity should be no more than 12 times the charging current that can be provided by the Inverter (e.g. a 5A charger can accommodate only 60AH (5*12=60)). In case the battery discharge is less frequent (say once in 10 days), then in such extreme cases the battery capacity can be increased to 20 times the maximum charging current of the inverter. In addition, the charging current provided by the inverter should be below the limiting current of the battery to ensure the battery does not get damaged during charging.

When connecting batteries multiple batteries in parallel, please note that the inverter’s battery charger should be able to provide the charging current required by each individual battery (e.g. if the limit current of one battery is “A” amps, for “N” batteries in parallel, the limit current for charging of inverter should be “A*N” amps). This is not a factor when connecting batteries in series as all batteries in series use the same charging current from the inverter.

Computer, Server UPS Questions

An inverter is a device that converts DC (Direct Current) power into AC (Alternating Current) power. For example, a 12V inverter will convert battery power available at 12V DC into AC power at 230V in India.

UPS (Uninterrupted Power Supply) is a device that normally provides back-up power supply for any electrical gadget. To do this, the UPS typically includes the inverter, battery and battery charger in one standalone unit. UPS units also provide protection against many electrical problems like over-voltages, brownouts, power surges etc. and in certain cases also communicate with the equipments they are powering.

We often use the terms interchangeably in India, as given our need for back-up power, a standalone inverter (that converts only DC power to AC power) is often not very useful and we invariably need a device that is also equipped with a battery charger and hence, a UPS.
UPS systems are classified into different types based on their topology, or, electrical design used. These are Offline UPS (also known as Standby UPS), Line-interactive UPS, and Online UPS (also known as Double Conversion Online UPS). The three topologies differ mainly in the level of power conditioning they provide when operated on utility power and on battery power. These topologies in the order of increasing quality of power they provide are: Offline, Line-interactive and Online.




Value proposition


Low cost, high efficiency (typically 95 – 98%), compact Uses battery during brownouts, limited or no protection against power irregularities, impractical over 2KVA Best value for Personal Computers

Line Interactive

High reliability, high efficiency (typically 90-96%), reasonable voltage conditioning Impractical over 5KVA, does not protect against all forms of power irregularities Most popular UPS – ideal for for small office, web and departmental servers and/or harsh power environments

On-line (Double Conversion)

Near ideal electrical output, highest protection against all power irregularities, ease of paralleling Lower efficiency (typically 80 – 90%), relatively more expensive under 5kVA Default choice for providing back-up power and protection to mission critical equipment and servers at data centers
UPS (standby/offline) & line interactive UPS takes about 4-10ms to transfer DC power to AC power when utility power is failing or abnormal, but UPS (online UPS) takes zero, therefore, usually UPS (Standby or offline) is used at home and Online UPS is used at Critical data workloads like Servers, meant for banking, insurance, where data loss or hardware loss cant be affordable.

Online UPS provides pure sine wave output which is same as the utility power and it is expensive In General, For Normal Computer Systems a UPS offline or Line interactive UPS is recommended, for Servers, Data centers, hospitals, Lifts, etc Online UPS is recommended!

Power Problems




Low Voltage

No Protection / Limited Protection Limited Protection Highest Protection

High Voltage

No Protection / Limited Protection Limited Protection Highest Protection


Highest Protection Highest Protection Highest Protection

Noise Interference

No Protection Limited Protection Highest Protection


No Protection / Limited Protection Limited Protection Highest Protection

Floating Frequency

Limited Protection Limited Protection Highest Protection
The choice of either a single phase or three phase UPS depends on the load that needs to be protected. UPS with single phase inputs are typically used when the protected load is less than 10kVA. When the total load to be protected is more than 10kVA, typically a UPS with three phase input is chosen, even where the inverter output is single phase. Larger UPS units with three phase input and three phase output are used when the load is more than 20kVA and the loads can be either single phase or three phase in nature. Three phase UPS are more compatible with a three phase DG set and these UPS systems can also be used to feed single phase loads, and with good load balancing, the DG does not need to be oversized.
UPS not only supplies AC power to loads while utility power failure, but also protects against unsteady utility power. It purifies AC power and provides overall power protection; it shuts loads down intelligently when utility power gets off; it turns loads on automatically when utility power recovers.
The transfer time from mains to battery power differs for different UPS topologies. In case of Home UPS (sinewave which is sometimes called as Off-line UPS), the transfer time is typically less than 10 milliseconds. in case of line-interactive UPS, this is typically less than 4 milliseconds. and in case of Online UPS, it is zero. Thus the switchover time for all UPS topologies are quick enough (one cycle in a 50Hz environment is 20 milliseconds) so that computer workstations will mostly never notices the lapse

Trouble Shooting Questions

If your battery or inverter is having over heat, then there is high chance of increasing of your electricity bills

Pls check your Inverter or UPS charging Voltage and amps, if it charging high amps usually more than 14amps for 150 AH, then there is chance of overheating of your battery. and also , if your inverter charging voltage should not cross more than 14 volts

If above point is not rectified, then you need to replace the battery or Inverter very soon!!
May be it is Relay problem, reset input & front power switch of the inverter. again, if it does not work, disconnect the battery connection and call Company Hotline or take local support!
May be the Battery is Weak, Recharge the battery and try again, If Battery is defective try to Replace new battery See if Power switch (on the front panel) is not pressed: press and hold power switch again and try!
AC input protector or MCB is tripped, Try to Reset the input MCB in MCB control box • AC input may be missing, check AC input connections & switch (fixed in wall, should be Switch should be in ON position)
Power failure is only one of power problems; the other ones such as high voltage, low voltage, spikes, sags & surges and noises & transients would damage or shorten life span of your loads, especially some refined equipments in telecom, network, medical, traffic etc.

Combo Questions

• Try to keep your inverter within 2-3 meters distance from main's MCB. It reduce wiring cost and Never put any metal or wet material on the battery. It may be a cause of fire due to short circuit or explosion • Must keep Both inverter and battery in same place. Battery wire comes along with the inverter, do not add more length to it • Battery needs regular maintenance , like top up of distilled water, so keep your inverter in easy reachable place. • Dont to keep inverter in kitchen. Bathroom, keep far from the children • Always keep your inverter in your hands is easy to operate and easy to trouble shooting. and Inverter some time generates heat while working, so do not keep it in air tight cupboard. It need Ventilation, if not, this reduces this battery life and Avoid Sunlight
Ideally an UPS or Inverter should be installed very closer to UPS and we recommend max within 5 feet away from batteries. If you increase this distance, you should use thicker cables to connect from UPS to batteries.

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