Maintaining UPS/car batteries

[umans]

@whiteangel
auroragroups@gmail.com

[umans]

@whiteangel
any update regarding UPS? did u check the backup time?

[talhawaleed]

Thanx to talhawaleed for starting this thread and sharing his knowledge.It motivated me and i read lot more stuff on batteries.I'm thinking to develop a small software utility that will calculate correct charging current,subtitle load,battery backup time and charging time according to given battery parameters.
one thing i want to correct,tlaha says somewhere in this thread that if battery is charged with 15,20 ampere current,its huge enough to run the AC.this is not true.
in ideal case(if ur UPS charger has 100% efficient)
Input power = output power
charger convert 220AC to 12V DC
if its charging at 20Ampare
220*I = 12 * 20
I = (12 * 20)/220
I = 1.09
as voltage is 220
P = 1.09 * 220 = 240watt
if efficiency of charger is 80%
then power consumed by charger when chraging 12 volt battery at 20 ampare is 300watt

Thanks for correcting me. Let’s attack the problem in backward flow

Suppose 24 Volts batteries is currently being charged at 20 AMP
We know that
Power = Voltage * Current
Power (Consumed during charging a Battery) = 24 * 20= 480 Watts
Obviously equivalence of this from AC line would be
Power (AC) = V * I
480 = V* I (AC)
We know V would be 220 Volts AC
480 = 220 * I
I (AC) = 2.18 Amperes

Only difference between AC and DC is that in AC current switches directions many times in a second where as In DC current flows ( One direction) from negative terminal to the positive terminal of the battery through some resistive load.

[umans]

Thanks for correcting me. Let’s attack the problem in backward flow

Suppose 24 Volts batteries is currently being charged at 20 AMP
We know that
Power = Voltage * Current
Power (Consumed during charging a Battery) = 24 * 20= 480 Watts
Obviously equivalence of this from AC line would be
Power (AC) = V * I
480 = V* I (AC)
We know V would be 220 Volts AC
480 = 220 * I
I (AC) = 2.18 Amperes

Only difference between AC and DC is that in AC current switches directions many times in a second where as In DC current flows ( One direction) from negative terminal to the positive terminal of the battery through some resistive load.

U r right bro.But UPS working on 24V battery bank usually use about 10 Amp for charging and 1 ton ac consumes about 5 Amperes.Anyways!!! thanx for sharing knowledge bro...

[talhawaleed]

Yes, sorry about that I was ignoring the (Pin=Pout) fact. Probably the AC which consumes 9 Amperes of current utilizes P=220 * 9 =1980 Watts of power per second and UPS which charges at 10 Amperes consumes= 24 V * 10 = 240 Watts of power per second. Correspondingly power drawn from AC line would be VI in=VI out , I in= VI out/V in =240/220 =1.09 Amperes continuous for 3- 5 hours

[umans]

That is for ideal case.u need to know the efficiency of inverter and charger to calculate the power drawn and power given to UPS respectively.
One more thing i want to add is that max charging current(Ah/10) for a battery is also a max current drawing limit for better performance and life of battery.
E.g if battery rating in 150AH the max limit of charging current is 150/10 = 15 Amp
and u should not draw more than 15 amp from battery.so max load on UPS running on 150Ah battery(ignoring efficiency of inverter) is 180 Watt
(All above calculation is for 12V battery)

I'll develop a software(whenever i get time) which will calculate all above factors for batter by just giving battary rating and UPS efficiency values.

[xzap042]

I guess you guys are forgetting that in AC P=IV not P=IV

i.e vector current and voltages, what you are calculating is only approx value of current. actual input current will be considerably higher considering power factor

[umans]

I guess you guys are forgetting that in AC P=IV not P=IV

i.e vector current and voltages, what you are calculating is only approx value of current. actual input current will be considerably higher considering power factor

Can u please explain....

[star2]

@talhawaheed

I have gone through your whole thread, excellent one, I admit.

I have just recently bought 2 batteries of Exide for my UPS NP130.

Two months are past and I have checked its water level today, the cells are dipped, though the problem is that from outside, its not that transparent that water could be seen.

Now, just give me points to maintain these batteries for long time as I am tired of purchasing new batteries every year.

What should I do first, where to bought water, which water ?? what type, and how to pour it into the battery.

Your detailed help in this regard would be highly appreciated.

Waiting for your quick response.

Light is going after every hour, means one hour coming, one hour on UPS, so keep this fact in mind :).

Regards.

Mustfeez.

[talhawaleed]

1) Adjust the charging Rate to 10 Amperes
2) Check the battery cutoff Voltage as this should be set to 28 Volts
3) 1 year is a very less time for battery to die
4) Normally with new batteries, level of the solution does not drop very quickly
5) Always use distilled water and try to prepare it your own self as this is already explained in this thread
If you will follow these simple steps then nothing will happen to your batteries for at least two years and most of the batteries dies because of bad UPS settings.

[star2]

Ok, please explain the procedure to adjust the charging rate to 10 Amperes.

From where to get distilled water, i cannot make it myself, somehow.

[usmanakbar1]

dear talha how are u,u will be fine inshallah, as i already told u that i had two exide batteries 190 one yr old i flushed them and charged but stilll the output voltage was not increasing beyond 170volts so i changed the defective one with new,the voltage is now 200v now the speed of the fans is ok the cutof voltage is 26volt but the speed and voltage drops after 50 mins useage ,which was 3 hrs with both new batteries what should i do increase the cut of voltage because it took thre hour 15 mins to reach the voltage across the batteries which was 26 is it ok ,at reaching 26 volts the charging rate was 7.5 amps at that point is it ok,iam afraid that increasing the cutoff voltage will damage my new battery as the old one might not get charged like new ,should i also replace the old one or increase the the cutoff voltage time and then see that it increase to 28 or not,the specific gravity is in green zonen all cells
in our area electricity goes evry 4 hrs for one hour plz reply
and also tell that at what voltage the baterries are fully charged
my house has five fans on ups on these batteris with 2000watt ups
i have lost yr mobile no if u can call me again plz 03149071613
thanks

[talhawaleed]

1) For two twelve volts battery, cut off voltage should always be set to 28 Volts for both old and new batteries.
2) Charging rate can be increased to 15-17 Amperes.
3) Output voltage under load shedding is simply amplification and is controlled by the variable present on the board. This should always be near to 255 to 245 Volts once system is 100 % charged. With passage of time as soon as batteries will become weak this will reach 220 Volts.
4) For few UPS, the current is controlled by the variable present on the UPS board where as for few you have to use alternate wire option available on transformer.
Star and Usman, I am repeating the same information over and over again. If you will read the entire thread then you will find out that I have already explained this and repeated this multiple times.

[mughees4]

Hi all!

I also had issue with my ups battery 150Ah so i washed my battery and filled it with new electrolyte that i prepared.

The problem is the gravity of electrolyte (when i prepared it in the tub) was 1270, but when i poured it into the battery suddenly its gravity dropped to 1130 and now after an overnight charging its gravity increased to 1160-1170.

So i am currently confused on what to do? is this normal? How can the gravity drop so quickly?

Also, when i prepared the electrolyte i used 1.85 litre sulfuric acid with 6.85 litre distilled water.

[talhawaleed]

Definitely it will drop below, as Acid is heavier then water so will accumulate at the bottom. Now is not the right time to check the gravity. Check this after 2 weeks as gravity will increase once your UPS will repeatedly charge and discharge.

Very normal behavior

If load shedding is more often in your area then increase the charging rate to AH rating/10.

[mughees4]

Yeah but after 20-24 hrs of charging it gave only 30min backup time on just 200W. My ups is Homage Vision 1000 with 600W max output.

And how do i adjust the charging current of my ups?

Also can you pm me your mobile number. I need your help.

[talhawaleed]

Looks like your UPS supports single 12 Volts battery. I hope you did not had a bad cell before you have performed a flush. The way to check this is by using a hydrometer before draining the entire Acid. If you have a bad cell before then this exercise may not help you but if you have performed the exercise before you cell has gone bad then it will prove to be very effective.
First of all, why 24 hours of charging????
1) Have you cross check the present charging rate, it may be very slow that is why this is taking 24 hours.
2) UPS should stop charging the battery once terminal voltage reaches 14 Volts.
Number of people have in person requested the advice on the UPS system and after testing the UPS, I have never advised them to directly go for a battery flush. First and foremost important thing is the right tuning of UPS and then secondary thing is this exercise.
First correct the reason which is causing this and then move onto the problem. Please PM me your cell number.

[a_n_memon88]

I bought two AGS 130 batteries for my 1000watts UPS on 11/3/2011. At that time the gravity was 1250. I constantly checked the electrolyte level and it never decreased now few days ago I noticed that charging time of my UPS has increased i.e before it used to completely charge the batteries in 75 mins now it takes 90 mins on same load. yesterday I measured its gravity and the gravity in all cells was 1170-1180 and the electrolyte level was as good as two months ago. i have never topped up the batteries. Now I am confused as to how come the gravity has decreased without any top up please help me out

[talhawaleed]

1) Always check the gravity once batteries are fully charged
2) If your area has an excessive load shedding going on then probably batteries might not be getting enough time to charge fully which can result in decrease in gravity.
3) If batteries are occasionally getting chance to fully charge its self and number of times load shedding time starts before it is fully charged then again you can expect the same outcome.
4) Try to adjust the charging rate to 13AMPS in order to meet the demand of present circumstances.
5) Normally once all the cells have same gravity then this indicates that batteries are in good condition.
6) Batteries should cut of charging once terminal voltage reaches 28 Volts. Most of the times this is one of the biggest culprit.

[saadzzz]

can i use A.c drainage water in battery plzz answer me...