A Comprehensive Guide For Maintaining Car/UPS Battery

25 1,001

Most of the times, people have problems related to car/UPS batteries where they find it an impossible task trying to justify their batteries’ are death within the first year. Normally they try to visit local battery’s shop where our illiterate technicians try their level best to convince them that the battery is dead and only way out is to buy new batteries. They immediately perform a load testing on discharged battery and show you where the needle is pointing without informing you about the sort of load they have inserted on the battery or at times they measure the reading of hydrometer of one or two cells then inform you regarding the faulty cell without giving you a proper reason. Most of the times the battery is not dead or acid within the battery does not have a right Specific Gravity or topped up with tap water. These batteries can easily be brought back to life by performing a flush and then charging it back for 2 to 3 times. If load testing is performed again on the same battery then you will be surprised to see that your battery was not actually dead as he was trying to convince you that it was dead. Secondly, the procedure which they follow in order to prepare the Sulphuric Acid with gravity of 1270 has many faults which directly reduce your battery life to half. Most of these problems reported (battery dies within a year of purchase) has directly to do with the way you are maintaining your batteries. If your UPS has been trying hard to charge an empty lead acid battery then I can guarantee that your battery will die immediately and there is nothing you can do to bring it back to life.

Sometimes you must have noticed that your UPS is always charging, either of the reasons may imply; because of sulphate built up on battery terminals (UPS is unable to deliver the current which is required to charge a battery), or it does not have fluid inside it which is necessary to charge the lead. In either scenario, you can very well understand that you are wasting energy which should be sufficient enough to run two Air-conditioners during summer season. As normal 145 AH battery needs 14-15 Amperes for charging where as your home Air-Conditioner demands 8 to 9 Amperes of current once compressor is running. So it is very important to maintain your batteries in order to avoid wasting the energy which also can give you high bills. Normally, once you purchase a UPS along with batteries, then you might notice a decrease in the output of UPS within first three months. Now my point here is that this is very abnormal behavior which occurs in every house these days. Different scenarios can cause similar problems as batteries convert chemical energy into electrical energy and chemical properties of battery changes the entire year, so if you will not cope up with the situation then you will experience similar scenarios of high electric bills and battery will die within a year of purchase. This topic should catch an eye of Audience who are using lead Acid batteries and local UPS being sold in every city. Further explanation is given with help of personal experiment performed in my office compound.

Similar scenario occurred with me three years back once I got interested in analyzing the procedure which is used by battery maintenance shops. They purchase Sulphuric Acid in drums and then mix it with tap water in 66 % by volume. They say that chemical reaction causes the water to boil which remove the oxygen molecules from the mixture hence results in giving up gravity of 1250 which they pour it in car battery.

A battery runs fine for minimum 2 years, where as, if it’s all about removing impurities from car battery then they are making a big mistake by adding tap water because it would boil the water but shall not guarantee the removal of impurities present inside the water. I have six batteries of 200 Amps each in my office which supports 15 computers running on them during heavy load shedding. In order to overcome the myth, I purchased the drum of Sulphuric Acid and mixed it with distilled water which I produced in my own lab. I took all my batteries outside and flushed it with tab water to remove all the deposits present inside the batteries. Flush was performed multiple times then batteries were refilled with Acid of 1280 gravity prepared within my office compound. From the past three years, I have been maintaining the gravity of my UPS batteries with Specific Gravity of 1280 by mixing the acid and distilled water as required. Even at the end of third year, my batteries are able to provide 90% backup time as compared to the time of purchase, even after excessive load shedding of 1 hour’s – 5-6 times a day from last three years. Flush is a periodic exercise which is performed at least once a year; I also have adjusted the output of my UPS to charge per battery rate at not more than 8 Amps. Similar procedure was adopted on all my three car batteries which have been running fine without a problem from last three years with mileage exceeding 80000 km each.

Now common problems why Lead Acid battery dies earlier are as follow

  • If fluid inside your battery has dried and your system is still charging the battery, then you would never be able to recover your battery.
  • Once you add Tab water inside your batteries, this causes your batteries to die earlier as impurities present inside the tap water directly attack the cell of a battery, hence reduces the capacity of battery to charge properly and deliver the same backup.
  • Deposits build up at the bottom of the battery or between the plates which cause the short circuiting of leads and few cells die. Flushing the battery removes those deposits between the plates, and this procedure should be adopted before any such incident occurs.
  • Specific gravity of the fluid inside the battery should be between 1200 -1275, that why you notice a decrease in UPS output under load shedding. Ideally Specific Gravity should be between 1250 -1275.
  • Sometimes Specific Gravity of UPS batteries is ok but you are not using distilled water.
  • Charging rate of UPS is very high which causes overcharging of batteries and your batteries don’t last longer.
  • Sometimes Sulphate buildup on battery terminals reduces the capacity to charge it self and deliver the current required.
  • If batteries remain in discharged state for long duration of time then it becomes very difficult to bring it back to the life.

In order to cope up with these situations, I would urge that you should always have distilled water stored and Acid with gravity of 1280 prepared with distilled water. Use hydrometer to test the specific gravity and add distilled water or Acid as required. You should also adjust the output of UPS in order to avoid over charging of the battery as that is another major reason when your battery die soon.

I have kept the topic fairly simple in order to provide you with basic information which can help you make your battery last long. I don’t intend to use any equations here as I would not like to confuse the audience but if you are interested then you can make a search on Google to know about the chemical reactions which occurs within a battery.



It is very easy to produce distilled water at home. By distilled water we simply refer to the water which is heated and changes into steam. Steam should be allowed to pass through some system which can condense the steam so that it can change its form back into liquid and this liquid can be collected in some separate container. This liquid will be free from all sorts of impurities and is called distilled water.


Specific gravity is measured in (kg/cu.m) for your reference as I won’t be repeating these symbols during this topic afterwards. Water has a specific gravity of 1000 where as Sulphuric acid has specific gravity of 1800. Once you mix 66% (in volume) of distilled water in 34% (in volume) Sulphuric Acid then you should get a gravity of 1240. But normally you end up getting a gravity of 1400 as lot of distilled water is evaporated during this process due to heat being generated. You can make later adjustments using distilled water once Acid has cooled down as at that time no heat will be generated. Always remember that battery will show increased gravity once charged and reduced gravity once discharged. Initially aim for gravity of 1250 and then you can take the reading after a week and make fine adjustments.

  • Always pour Acid on distilled Water not distilled water on Acid.
  • Wear Rough Clothes, Glasses and gloves if possible.
  • Keep the Acid and Mixture out from the reach of Children.
  • Lot of heat would be generated during this process so be very careful.
  • Always Use plastic Container not Metal.
  • Mixture will take minimum 24 hours to cool down.
  • Never pour the mixture inside the battery once it’s hot.
  • 64 % distilled water should be Mixed with 36 % Acid by Volume.
  • You may end up getting a gravity of 1400.
  • Keep hydrometer with you and only check once fluid has cooled down.
  • You can perform later adjustments by pouring more distilled water on the mixture once it has cooled down and at that time no heat will be generated.
  • Use Plastic bottles to store the mixture.
  • Always Label it as “Very Dangerous Sulphuric Acid with Gravity ABC “.
  • Keep it in safe place where no one other then you can touch it.
  • Container used for producing the mixture should never again be used for taking bath.
  • Don’t allow anyone to misuse the Acid for hurting anyone.


Procedure which I followed was that I took the batteries outside and flushed it with tap water 5-6 times. People normally prepare the mixture of (Espom Salt + distilled water heated at 66 C). Pour the mixture inside the battery and then shake the battery so that mixture can make its way to every cell. Once the mixture has cooled down then they charge the batteries for several hours in order to remove sulphate deposits from batteries. . This procedure is used to recondition old batteries which can still provide you with an output of minimum 10 Volts. You will have to discharge and recharge it for multiple times. After a day or two, perform another flush and then pour the new mixture of acid inside the battery.


Most of us are using the similar local UPS sold in market. The only problem with these UPS is that they have few parameters which at times are not adjusted properly. Now once you buy these UPS without testing them, then you may end up losing many electronic equipments and since charging rate of UPS is not adjusted according to the battery which is also why battery doesn’t last longer.

By rule of thumb the correct charging rate of UPS is its Amp Hour rating divided by 10. For 145 AH battery; the correct charging rate is 145 AH/10 is 14.5 Volts. Anything above this would be termed as fast charging which would damage your batteries in long run. Slow charging is good for batteries but you have to prepare yourself for next load shedding.

You should always ask local UPS shops to adjust these parameters according to specification given below. If you are interested in learning then ask him to do it in front of you. Mark those parameters with paper tape so that you don’t forget once you do it yourself.

  • These UPS have a PCB card which has many variables.
  • These variables can be adjusted using a screw driver.
  • During load shedding the Output of the UPS is much more than normal Voltage.
  • Adjust the variables such that your Output Voltage should never exceed 265 Volts once batteries are fully charged.
  • Adjust such that once output voltage reaches 220 Volts then your UPS should trigger the alarm and should shutdown within 10 seconds.
  • Adjust the charging rate of each battery such that (AMP HOUR rating divided by 10).
  • Slow charging is very good for batteries but if it is slower than Amp Hour rating divided by 10 then you may not be prepared for next load shedding.
  • UPS should stop charging your batteries once the output voltage of both the batteries reaches 28 Volts.
  • During Load shedding, once output of batteries (where two batteries are connected in Series) reaches 20 Volts then Alarm should be triggered and UPS must be shut down immediately. Also note the output of UPS at that instance as it should not be less than 220 Volts otherwise you will end up losing many electronic equipments.
  • Always keep your UPS line separate from main line.
  • Your UPS should shutdown immediately if load exceeds the maximum capacity. UPS shops have different bulbs installed on board with different Powers.
  • Always test under full load so that you are aware about the maximum load your UPS can take. Now, your computers should be safe under these configurations.
  • You will need a good quality Voltmeter and AMP meter.
  • Since chemical properties of battery’s changes the entire year so you will have to check your tuning after every few months which you can easily do with help of a Voltmeter, Amp-meter & hydrometer.
  • Always remember that current divides in parallel configuration and Voltage remains same in parallel configuration so you should add many batteries on your UPS in parallel or series configuration which ever suits the configuration.


You should be aware of these terms as they are very simple and will give you the right idea about the correct charging and discharging rate of lead Acid batteries. Lead Acid batteries are ideal for scenarios where your load demands very high current for short duration of time such as starting the car that’s why many people are interested in knowing CCA or CA rating of battery before buying them.


Cold Cranking Amperes (CCA) is measure of amount of current your battery can deliver at 0 F for 30 seconds, once both terminals of battery are shorted and voltage does not drop below 7.2 Volts for 12 Volts battery.


Some time battery comes with CA rating specified for 32 F. high CCA rating is typically used for starting application but not referred to deep cycle batteries.

Never short your battery terminals as lot of heat is generated during this process and you may end up destroying your batteries but this is exactly what happens once you start your car. Also note that this is how a load testing is performed.


Normal batteries available in market come with AH (AMP HOUR) rating which means that 145 AH battery can deliver 7.2 Amperes for 20 hours before it would need serious charging again or 14.5 AMPS for 10 hours before it requires charging again. AH rating is expressed in number of amperes a battery can deliver for 20 hours which is calculated by dividing AH rating by 20.


In order to get the best service from your batteries the batteries should not be discharged at a rate more than AH/10, for 145AH battery is 145 AH/10 =14.5 Amperes. But it is ok to discharge a battery with AH rating divided by 6, 4 ,3 so this means that you can discharge your 145 AH battery at rate 145/6= 24 AMPS , 145/4=36 AMPS, 145/3= 48 AMPS but don’t expect it to last for 4 hours. In case of UPS, I am unaware how much load you have inserted and number of batteries you are using in parallel or series but you can use Ampere meter to observer the load on your batteries during load shedding and if you see that the rate on each battery is more then try to add more batteries to your UPS as current divides in parallel.


When you are charging your batteries then right rate to charge a battery is you’re AH rating divided by 10. That for 145 AH battery the right charging rate should be 145/10=14.5 Amperes. Slower charging is good for batteries but you have to be prepared before next load shedding. Anything above AH/10 is termed as fast charging which would damage your batteries in long run but you can do it for few times if your are monitoring the process.

Entire purpose of this topic was to highlight the mistake which our illiterate technicians are making while selling the batteries which reduces the life of your battery to half at times once you purchase it. Secondly, topic has also highlighted mistakes which general public is making while dealing with batteries as they die sooner and they are wasting a lot of power which can comfortably run two Air-conditioners once, they are mismanaging the system. I don’t recommend you to prepare the Acid by your own self as this is a very risky task where individual can easily hurt himself but least you can do is use distilled water, check Specific Gravity of Acid inside batteries by using hydrometer, clean battery terminals on time and maintain a proper tuning of UPS.

Google App Store App Store
  1. Hamza says

    thanks alot bahi…..very use full for every one.

  2. kashif says

    well on the issue of over charging you discussed two issues
    a) the content of batter has dried
    b) or due sulphates over terminals
    these both problems are concerned with disorder of battery
    what will you say over misconfiguration or disorder of the invertor that over charges the battery and ruins it .

  3. Talha says

    If you will read the article carefully then you will realize that it says “You can control the charging rate, Cut off voltage once fully charged, Maximum output Voltage on UPS line, Minimum output Voltage on UPS line before it should shut down and this also corresponds to the voltage on batteries” directly from variables present on UPS board.

  4. Rajkumar Lodhi says

    I have a base terminal 180AH flat plate battery which I’m using with luminous 800VA inverter. the problem is, after completing almost 2 years the battery is giving only 3 hours backup on 100 watts load, instead of 12 hours on the same load as it has given earlier. In two years battery has drunk 15 liters DM water. warranty is out so I am really in a fix. It would be a great help If you could suggest me some way.

  5. Usman says

    If my UPS input capacity is 600 watts how can it consume 14 amperes? As it is 1/3 that of a split type 1.5 ton airconditioner which has input capacity of 1900 watts. So it should consume the same proportion of current as well.

  6. Urban says

    Normal 145 AH battery needs 14-15 Amperes for charging where as your home Air-Conditioner demands 8 to 9 Amperes of current once compressor is running.
    This needs more clarification. Battery are using 12 volt where as Air-Conditioner is using 220 volt. It means normal 145 AH battery consumed power is (15×12 = 180) is 0.180 watt and Air-Conditioner consumed power is (9×220 = 1980) is 2 watt. Power is calculated by multiplying current with volt. Battery power is 0.0180 watt and Air-conditioner power is 2 watt. WAPDA Bill charging is watt based. I watt is 1 unit.

  7. Usman says

    This means 14 amps is UPS output current. What’s the input current?

  8. Shamron Suri says

    Dear Mr. Talha Malik ,
    I am really impressed by your knowledge and very much grateful that shared your knowledge with us.
    I will try to follow your instructions very carefully hope my batteries also last of 3 years instead of 1 year
    Thank you once again.

  9. M. Bilal says

    Fix your UPS Battery.

    Don’t throw or sell your old UPS or Car batteries for few hundred when you have an option to restore.

    UPS/Car battery performance decreases due to sulphation coating on lead plates. To desulfate a lead acid battery use ‘Battery Energizer’ liquid. It removes the sulphur deposits from lead plates and restores your battery like new. You can get Battery Energizer http://www.gobuy.pk, shipping is free all over Pakistan. I have tried this and it works and also very cheap in cost.

  10. hassan says

    I want to ask Talha Malik bahi is that is the Air Condition water is pure or not. the video is removed from youtube please upload again.

  11. Muhammad Ahmed says

    Talha would it then not be better to use dry batteries then these liquid acid batteries with a UPS ?

  12. M Adeel Qureshi says

    Very Very Helpfull.

  13. Umar Rasheed Baig says

    great and informative!

  14. Nomi Khan says

    Its really a very useful info.

  15. Irtaza Ali Mir says

    how many day battery will be ok if u don't start your car.

  16. Waleed Khokhar says


  17. Sharafat Ali says

    valuable favour of all users of ups. thanks

  18. Hanif Bhatti says


  19. Hamzah Shahid says

    nice info!
    check this site too.http://scienceandinfotech.blogspot.com/.

  20. Rahemeen Asim says

    Thank you for great knowledge. I have one question. The smartups are coming with two fans in ups one fans always running. Even when disconnected from main supply plug. (Meaning using battery to run). Can this effect charging of batteries as contiunously charging or weaken the batteries? Thank you

  21. Anonymous says

    Very useful info sir..thanks a lot

  22. Uttam Kumar Sarkar says

    Buy Eaton and Powerware UPS and power backup systems in Australia through Power Backup Solutions. Place an order and protect your power today. More information:-http://powerbackups.com.au/

  23. faisal says

    The article is very good, except for the load consumption calculation. Yes Urban is right the current is on the DC side 12v not 220v.

  24. Syed Hussein El-Edroos says

    Thank you. Although I have been working with batteries for over 30 years, I have learnt many new things.

  25. Syreeta Albim says

    my colleague needed USSS SSF 1604 a few weeks ago and used a great service that hosts an online forms library . If people are searching for USSS SSF 1604 too , here’s a http://goo.gl/XZPECg

Leave A Reply

Your email address will not be published.