PERSONAL EXPERIENCE
Three years back I got interested in analyzing the procedure which is used by battery maintenance shops. They purchase Sulphuric 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 batteries. Batteries run fine for year or two where as I think if it is all about removing impurities from car batteries then they are making a mistake by adding tap water which would off course boil the water but would not guarantee the removal of impurities present inside the water. I have six batteries of 200 Amps each in my office which can support 15 computers during heavy load shedding. In order to overcome the Myth, I purchased a drum of Sulphuric Acid and have mixed it with distilled water which I have produced it in my own lab. I took all my batteries outside and have 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 1250-1270 gravity prepared within my office compound. From last three years I have been maintaining the gravity of my UPS batteries up to 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 hourās; 5-6 times a day from last three years. Flush is a periodic exercise which is performed at least once a year also I have adjusted the output of my UPS to charge per battery at rate not more than 8 Amps.
LESSONS LEARN:
1) If electrolyte is prepared with tab water then batteries will die much earlier than its actual life.
2) Wrong UPS settings is yet another major factor which contributes in killing your batteries much earlier.
3) With wrong combinations of both, you will start to experience problems with batteries within first three months. Having understood the issue, My two 220 AMP-HR batteries connected with my UPS at home powers the entire house lighting, fans and runs flawlessly without much reducing the electrolyte and backup time even after two years.
[U]HOW TO ADJUST UPS
[/U]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 most of the times are not adjusted properly. Now once you buy these UPS then try to get it adjusted at shop before bringing it to your home.
By rule of thumb the maximum allowable charging rate of Lead Acid batteries are 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 if intensity of load shedding is frequent then probably batteries wonāt be prepared before it enters next cycle of load shedding. So you need to look into your circumstances before adjusting this figure but in circumstances you should go above maximum allowable charging rate.
You should always ask local UPS shops to adjust these parameters according to specification given below. If you are interested in learning them then ask him to do it in front of you. Mark those parameters with paper tape so that you donāt forget once you do it yourself. Also try to work these settings in your mind first so that you may directly dictate the electrician.
1. These UPS have a PCB card which has many variables.
2. These variables can be adjusted using a screw driver.
3. During load shedding the Output of the UPS is much more than normal Voltage.
4. Adjust the variables such that your Output Voltage should never exceed 265 Volts once batteries are fully charged and put into backup mode. 5. Adjust such that once output voltage reaches 220 Volts then your UPS should trigger the alarm and should shutdown within 10 seconds. 6. Adjust the charging rate of each battery such that (AMP HOUR rating divided by 10). E.g For 200 AMP-HR batteries, I can keep it somewhere closer to 15 Amperes but will never exceed 20 amperes. 7. Slow charging is very good for batteries but look into your circumstances as batteries will take more time to charge its self and you need to the batteries to be prepared for next cycle of load shedding. 8. UPS should stop charging your batteries once the output voltage two batteries connected in series reaches 28 Volts and for single battery UPS system, it reaches 14 Volts. This is termed as cutoff Voltage. 9. During Load shedding, once output of batteries (where two batteries are connected in Series) reaches 21 Volts then Alarm should trigger 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 sensitive electronic equipments such as TVās, computers and routers will start to restart its self. 10. Always keep your UPS line separate from main line.
11. Your UPS should shutdown immediately if load exceeds the maximum capacity. UPS shops have different bulbs installed on board with different Powers to adjust these settings on UPS system.
12. 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.
13. You will need a good quality Voltmeter and AMP meter.
14. Since chemical properties of batteryās 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.
PREPARING ELECTROLYTE:
I donāt recommend that you prepare the electrolyte at home as mixing sulfuric acid with distilled water produces a lot of heat which can severely hurt any individual. If you can buy the electrolyte of 1250 gravity from some company like PRYO chemicals then thatās a best possible scenario. Otherwise, follow below.
HOW TO PRODUCE DISTILLED WATER
It is very easy to produce distilled water at home. By distilled water we simply refer to the water which is heated then it changes its form into steam. Steam should be allowed to pass through some system where it can condense so that it may 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.
I have used a pressure cooker, air conditioning coils, rubber pipes, two plastic containers one for dipping the coils into cold water so that steam inside the coil can change its form back into liquid and other end connected to rubber pipe so that now distilled water can be collected into a second plastic container.
HOW TO MIX ACID WITH DISTILLED WATER
Specific gravity is measured in (kg/cu.m) for your reference as I wonāt 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 by using electrolyte prepared earlier of 1400 gravity or 1350.
1. Always pour Acid on distilled Water not distilled water on Acid.
2. Wear Rough Clothes, Glasses and gloves if possible.
3. Keep the Acid and Mixture out from the reach of Children.
4. Lot of heat would be generated during this process so be very careful.
5. Always Use plastic Container not Metal.
6. Mixture will take minimum 24 hours to cool down.
7. Never pour the mixture inside the battery once itās hot.
8. 64 % distilled water should be Mixed with 36 % Acid by Volume.
9. You may end up getting a gravity of 1400.
10. Keep hydrometer with you and only check once fluid has cooled down.
11. 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.
12. Use Plastic bottles to store the mixture.
13. Always Label it as āVery Dangerous Sulphuric Acid with Gravity ABC ā.
14. Keep it in safe place where no one other then you can touch it.
15. Container used for producing the mixture should never again be used for taking bath.
16. Donāt allow anyone to misuse the Acid for hurting anyone.
HOW TO PERFORM FLUSH
Procedure which I follow is that I fully charge my batteries, then take the batteries outside, drained the electrolyte in proper sewerage line while I already have an access to new electrolyte which was prepared earlier before performing this procedure and have the batteries flushed it with tap water 5-6 times. Later put the battery in upside down position for 30 minutes before pouring new electrolyte back in.
DIAGNOSING ISSUES WITH UPS SYSTEM (BATTERIES AND UPS)
You cannot diagnose an issue with a UPS system without having an access to Voltmeter, AMP-METER and hydrometer.
1. If fluid inside your battery has dried and your UPS is trying hard to charge the batteries, then you would never be able to recover your battery after such an abuse. Forget it and disposing it is a best option.
2. If electrolyte filled was prepared with tab water, even then you should fine tune your UPS but there is no guarantee how long the batteries would last because of tab water factor.
3. If you discover earlier that UPS takes more time to charge the batteries then you need to verify the charging rates and cutoff Voltage at battery terminal. 90 % of your problems will be solved by looking into these two variables.
4. If you feel that UPS keeps on charging the batteries then most likely charging rate would be set to a very low value or cutoff Voltage is not set to 28 Volts .
b) If these two factors are set properly then look into the level of electrolyte.
c) if above two factors are ok, then measure the specific gravity of all individual cells and look for the variation.
5. If UPS charges your battery bank very quickly whereas you are not getting a good backup time then again check charging rate as it may be set above the maximum allowable charging rate or cutoff Voltage maybe set to low value.
I will keep on editing this, and will add more causes with passage of time.
WORST CASE SENARIO IF YOU DONāT HAVE AN ACCESS TO DISTILLED OR DE-IONIZED WATER AND WANT SOMEONE TO PREPARE ELECTROLYTE FOR YOU.
Try to get hold of filtered water and boil it in some big container. Once water starts boiling then keep boiling it for next 25-30 minutes and let the water cool down in same container. Impurities will settle down at bottom of the container once cooled down. Try to separate the clean water from the impurities present at the bottom. You can repeat this process again but never use this for topping up the batteries later but can be used for preparing the electrolyte initially.
