Maintaining UPS/car batteries

[longdrive]

i have been monitoring the battery closely for first few days and today i saw very small blackish deposit under one of the cap.
Its been just six days of use and i used a branded electrolyte so i hope this should not be due to impurities.
I am using homage ups which keeps giving trickle charge.

[homayoon]

Very informative and helpful thread, has encouraged many of us complacent people in trying things by ourselves. Hats off to Talha Waleed and others for dedicated efforts in this regard. I stumbled upon some more info which i believe will be helpful to many.
1. If difference of specific gravity is more than 50 pts (0.050) between cells, it means the battery is no more.
2. 40 to 80 AH Batteries. CCA (cold cranking amperes) rating for such batteries is between 350 to 560 amperes and RC (reserve capacity) is from 55 to 115 minutes, while power output for such batteries will be in the range of 2000 to 4000 Watts.
3. Specific Gravity Ratings
a. Ideal - 1.265 (Theoretically 1.270)
b. 3/4 Charge - 1.225 (Charge the battery)
c. 1/2 Charge - 1.190 (Sulfation about to begin)
d. 1/4 Charge - 1.155 (Severe discharge, slow charging is required)
e. Fully Discharged - 1.120 (Replacement, some can be restored at slow charge)
4. Typical charging rates for fully discharged batteries are as under (Larger batteries having AH ratings higher than 150 can approximate accordingly):-
AHRate-5amp-10amp-20amp-30amp-40amp
AH <50-10 hrs- 05 hrs - 2.5 hrs- 2 hrs -------
50to75-15 hrs- 7.5hrs - 3.25 hr- 2.5hrs- 02 hrs
75to100-20hrs- 10 hrs - 05 hrs- 03 hrs- 2.5 hrs
100to150-30hrs- 15hrs - 7.5 hrs- 05 hrs- 3.5 hrs

[Xulfiqar]

please check your hydrometers too, some are faulty and show incorrect reading,

to calibrate - find a shop keeper with a digital scale, take a 1 litre bottle and weight it empty. write it down, fill bottle with exactly 1 litre of water - and mark the level with a marker, drain the water and fill with electrolyte to your made mark and weight it again. subtract the bottle empty weight from the total weight to get your SG. compare it to the hydrometer reading.

[ahmad147]

Great thread..

Please let me know of honest and trustworthy Battery service shop in Lahore

[dms664]

@kulachiwal

CASE 1

Now imagine how is it possible that if you will buy one battery of 195 AH where as other of 215 AH. Even if you will charge both with 15 Amperes of current, then one will be charged earlier and then remaining of the time once other is being charged then this one is being subjected to abuse.

CASE 2

Imagine that once first one is completely charged and then charging stops this implies the other battery has not been completely charged and Over period of time second battery will be damaged very soon.

Probably he must have told you this because of non availability of battery of same capacity in his store. You must have slapped his face with your chapples that never ever he dares gives wrong advice to anyone.

What if the batteries of different amps are wired in parallel?

[Xulfiqar]

they would be - wouldnt they?

[homayoon]

Dear Whiteangel,

DISCHARGING RATE

In order to get the best service from your batteries the batteries should not be discharge more than @ AH/10 which 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 @ 145/6= 24 AMPS , 145/4=36 AMPS, 145/3= 48 AMPS but don’t expect it to last for 4 hours.

Now this statement mentioned at page 2 of the thread has puzzled me, is this statement correct? we all know that the discharging rate in a ups battery is dictated by the power of ups and not the battery AH so as per my reckoning a battery attached to a 1000 W ups can at max be discharged at the rate of 4 amperes (P=IV). On the the other hand, a car battery can be discharged higher than the cold cranking amperes (cca) at normal temperature but off course for a very limited period of time (30 secs). Usual CCA for a 75 AH battery is somewhere close to 550 amperes. Please check the veracity of the above statements.

      My second question, if two batteries of 180 AH each are attached with a ups in parallel, do we need to charge these batteries at the rate of 18 amps or 36 amps.

       Lastly, all car battery training manuals describe the battery as 100% charged at 12.6 Volts and fully discharged at 12 V, however, in the thread it has been mentioned more than once that the ups must charge the batteries upto 14 V and a battery must not get discharged beyond 10.5 V. So why is this anomaly.

Thanks in anticipation.

[Alcapone]

my car's battery suddenly half died. when i tried lifting/grabbing the cables attached to one of the terminals, the battery came to full life. as soon as i took my hand off, current got weak again. I checked and rechecked all the cables and bolts but nothing happened. took it to the mechanic and he instantly said that one of the cells had stopped working. i changed the battery and now its fine. was it just a dead cell or something got loose within the battery?

[talhawaleed]

Now this statement mentioned at page 2 of the thread has puzzled me, is this statement correct? we all know that the discharging rate in a ups battery is dictated by the power of ups and not the battery AH so as per my reckoning a battery attached to a 1000 W ups can at max be discharged at the rate of 4 amperes (P=IV). On the the other hand, a car battery can be discharged higher than the cold cranking amperes (cca) at normal temperature but off course for a very limited period of time (30 secs). Usual CCA for a 75 AH battery is somewhere close to 550 amperes. Please check the veracity of the above statements.

My second question, if two batteries of 180 AH each are attached with a ups in parallel, do we need to charge these batteries at the rate of 18 amps or 36 amps. Lastly, all car battery training manuals describe the battery as 100% charged at 12.6 Volts and fully discharged at 12 V, however, in the thread it has been mentioned more than once that the ups must charge the batteries upto 14 V and a battery must not get discharged beyond 10.5 V. So why is this anomaly.
Thanks in anticipation.

Lets attack your problem, Two batteries of 180 AH are connected to 1000 W UPS so according to the above statement they can be discharged at (AH rating /10= 18 Amperes ) , (AH/6 = 30 Amperes), (AH/4= 45), (AH/3=60 Amperes).
If you would have studied about transformers then you would agree
VI (AC) = VI (DC)
And since you UPS is of 1000 W
P (AC) =VI
We know, ideally V should be 220 Volts
1000=220 * I , => I= 4.54 Amperes
But AC voltage is Stepped down using transformer and then converted into DC voltage which is supplied to the battery.
So here if V=24 Volts and P= 1000 W then this implies that I=P/24 , I= 41.66 Amperes.
So if you will try to extract current more then I= 41.66 Amperes from your UPS then ideally it should have a protection switch which should immediately turn off the UPS.

Conclusion:

1) Now what is the recommended AH rating of the battery specified for your specific UPS
2) Probably you are using battery with high AH rating then specified by the user Manual.
3) Referring to the last paragraph, you need to cross check your facts.
4) Only thing 1000 W UPS says is if you will try to extract or discharge your batteries at rate more then I(DC)=41.66 Amperes then UPS will shut down immediately as it is not meant to support such a high current.

Chill as it does not matter in your case, probably you need to check the maximum charging current of your UPS as I believe that it would take more time for your UPS to charge 180 AH battery.

[ahmad147]

Any reliable Battery shop in Lahore who is using distilled water mixture as I want to buy a new battery for my car

[homayoon]

Thanks for taking the pains to answer my questions however, my source for question no 3 are:-
Training Manual
Battery Service
http://www.autoshop101.com/forms/h6.pdf
Thanks again

[longdrive]

@talhawaheed
do you have any idea about blackish deposits under battery caps. I think this is due to lead falling off the plates which happens as batteries are aging but is it normal for new batteries?

[talhawaleed]

@talhawaheed
do you have any idea about blackish deposits under battery caps. I think this is due to lead falling off the plates which happens as batteries are aging but is it normal for new batteries?

Small blacking deposits underneath the battery cap is the indication that you battery is being charged with either high current or is being over charged. Ideally black deposits should not exist underneath the battery caps but in practical life they are always there. Maybe you cannot avoid them in Cars but this is a very good indication that battery is being over charged. In case of UPS you should get your UPS system adjusted and then wash the caps with surf. Then next time observer that how much time does it takes to turn black again. If it is taking 4-5 months and intensity is low then probably your batteries are not being abused very often. But if you find they are appearing within days then this is an indication that you should take action immediately.

EXAMPLE CASE: In my Honda city car, it takes 5-6 months before I observer the blackish deposits underneath caps but in Liana just after a month or two I can see the blackish deposits appearing underneath the battery caps. One of the major reasons I had to change Liana’s battery after mileage of 30k where as the battery with similar capacity lasted in Honda for 80k km.

[homayoon]

Lets attack your problem, Two batteries of 180 AH are connected to 1000 W UPS so according to the above statement they can be discharged at (AH rating /10= 18 Amperes ) , (AH/6 = 30 Amperes), (AH/4= 45), (AH/3=60 Amperes).
If you would have studied about transformers then you would agree
VI (AC) = VI (DC)
And since you UPS is of 1000 W
P (AC) =VI
We know, ideally V should be 220 Volts
1000=220 * I , => I= 4.54 Amperes
But AC voltage is Stepped down using transformer and then converted into DC voltage which is supplied to the battery.
So here if V=24 Volts and P= 1000 W then this implies that I=P/24 , I= 41.66 Amperes.
So if you will try to extract current more then I= 41.66 Amperes from your UPS then ideally it should have a protection switch which should immediately turn off the UPS

Thanks bro now u have made me understand that i and u are basically saying the same thing. 83.32 DC V=4.17 AC V (assuming wapda at 240V, i rounded it off to 4 V). But dont u think think that its better to calculate the amperes in AC as all household appliances have their markings in AC Volts.

Conclusion:
1) Now what is the recommended AH rating of the battery specified for your specific UPS
2) Probably you are using battery with high AH rating then specified by the user Manual.

I would like to elaborate about my ups further:
I bought this ups (1000w) from a local vendor who assembles these machines locally and as such there is no user manual to be referred to:P. He boasted that i could attach any number of batteries with it as far as they were in parallel arrangement. Now this ups is installed at my workplace since 3 months and is sharing a load of 4 ceiling and 1 pedestal fan and 3-4 energy savers for 24 hours a day and 30 days a month:). It has provided good services for a couple of months however the speed of fans was quite slow. It went out of order and was repaired again by the same ups wala and installed again a week back but is out of order again now. The performance of batteries this time around was reduced to 1 hour each (i have quit parallel arrangement) and the fan speed was painfully slow. I have sent it again to a new ups wala and this time i will check the charging rate etc for further reference.

3) Referring to the last paragraph, you need to cross check your facts.

My sources for battery voltage are (12.6v=100%, below 12v=0%):
Training Manual
Battery Service
http://www.autoshop101.com/forms/h6.pdf
Bundle of thanks

[Xulfiqar]

the standing voltage of a battery would be 12.6V but you need 13.8 14.0V to fully charge the battery back into service specs. the 14.0 is valid for the lead antimony batteries that are available, for lead calcium you may need to increase to 14.8 to 15.0 Volts, for them to start gassing.

[xzap042]

anyone has experience of VOLTA IT series batteries? I've heard they have thicker plates and can be approximated as deep cycle batteries for UPS operation

[homayoon]

the standing voltage of a battery would be 12.6V but you need 13.8 14.0V to fully charge the battery back into service specs. the 14.0 is valid for the lead antimony batteries that are available, for lead calcium you may need to increase to 14.8 to 15.0 Volts, for them to start gassing.

Thanks Xulfi bro for the reply

[jz]

as xulifqar bhai stated,one needs 13.8-14v for the dry batteries,i had serious voltage dropping issues due to a heavy sound system but,upgrading to a 60amp batery n adding a voltgae stabilizer helped alot to keep the votlage constant at 14.6v in my car

what is the disadvantage of conncting the battery + directly to the generator,i know it does help in quicker charging but does the battery life shorten with it?

[Xulfiqar]

as xulifqar bhai stated,one needs 13.8-14v for the dry batteries,i had serious voltage dropping issues due to a heavy sound system but,upgrading to a 60amp batery n adding a voltgae stabilizer helped alot to keep the votlage constant at 14.6v in my car

what is the disadvantage of conncting the battery + directly to the generator,i know it does help in quicker charging but does the battery life shorten with it?

the thicker the wire the more voltage drop is expected for a DC circuit of low load, as you are never on full power draw all the time, you dont need a thick cable all the time. and if you connect it direct to the battery and put the sense wire (denso 3 wire type alt) directly to the main wire at the alternator, the alternator will see that the battery voltage is full at partial load - while it may not be as the thick wire may be "eating it up"

[jz]

the thicker the wire the more voltage drop is expected for a DC circuit of low load, as you are never on full power draw all the time, you dont need a thick cable all the time. and if you connect it direct to the battery and put the sense wire (denso 3 wire type alt) directly to the main wire at the alternator, the alternator will see that the battery voltage is full at partial load - while it may not be as the thick wire may be "eating it up"

the wire isnt v thick,ive used 2 8 guage wires for it