Maintaining UPS/car batteries

[Khurrammoon]

See, all what you are telling me is very easy to diagnose. Next time, place a multi meter on the terminals of the battery and measure the Voltage. Voltage after two to three hours of continuous charging, Voltage once light has gone for hardly 5 minutes and it?s been hours since inverter still charging the battery. Now, by doing so you will find the real truth behind things such as Maybe UPS is trying hard to take the Voltage above 14 Volts and does not cuts off charging or Maybe charging rate has slowed down in later stages of charging that?s why its taking more time or maybe Variable which sets the cutoff charging Voltage has gone bad and UPS simply does not stops charging. These variable used to adjust the output Voltage, Cutoff Voltages are nothing more the variable resistors and at times they do go bad. Replacement of variable resistors are the only solution but this has to be diagnosed first using the technique as described above. These resistors are worth 30-40 Rs but the technician who will change it for you will try to rip you off.

Talha Bhai here are the readings that you asked for.
Inverter remained off for 20 hours and reading on battery terminals was = 12. 41V on (20V voltage DC selector of Multi-meter).
When I turned on the inverter gradually reading increased to 13.65 V within 2 minutes and then kept on increasing with the passage of time.
After one hour of charging= 13.68V to 13.69V.
After 2 and half hours of charging inverter did not terminate the charge and then I turn off the inverter and then turned it on within 3 seconds and it terminated the charging.
Reading at battery terminals at cutoff was 13.69V.
Disconnected the input to inverter and there was zero load on the inverter for 5 minutes. Reading= 12.50V after 5 minutes.
Then turned on the inverter and it took 28 minutes to charge the battery and automatically terminated the charging by itself. Reading 13.69V.
Then I put 30 Watts load on inverter for one hour and reading after 30 minutes = 12.08V, after one hour= 12.03V and when light came back inverter kept on charging the battery for 2 and half hours and then I used on-off technique three times but it did not work and then I turned off the inverter.
Reading at that time was = 13.69V on 20 Volt dial of multi-meter, 13.7 on 200 volts dial and 14V on 500 volts DC dial.
Battery did not heat up at all during the long charging cycle. Now tell me is there some thing wrong with the battery or inverter?

[talhawaleed]

Talha Bhai here are the readings that you asked for.
Inverter remained off for 20 hours and reading on battery terminals was = 12. 41V on (20V voltage DC selector of Multi-meter).
When I turned on the inverter gradually reading increased to 13.65 V within 2 minutes and then kept on increasing with the passage of time.
After one hour of charging= 13.68V to 13.69V.
After 2 and half hours of charging inverter did not terminate the charge and then I turn off the inverter and then turned it on within 3 seconds and it terminated the charging.
Reading at battery terminals at cutoff was 13.69V.
Disconnected the input to inverter and there was zero load on the inverter for 5 minutes. Reading= 12.50V after 5 minutes.
Then turned on the inverter and it took 28 minutes to charge the battery and automatically terminated the charging by itself. Reading 13.69V.
Then I put 30 Watts load on inverter for one hour and reading after 30 minutes = 12.08V, after one hour= 12.03V and when light came back inverter kept on charging the battery for 2 and half hours and then I used on-off technique three times but it did not work and then I turned off the inverter.
Reading at that time was = 13.69V on 20 Volt dial of multi-meter, 13.7 on 200 volts dial and 14V on 500 volts DC dial.
Battery did not heat up at all during the long charging cycle. Now tell me is there some thing wrong with the battery or inverter?

SO far, the reading which you have quoted are within aspect. But why do you turn off the UPS after two hours of charging. Let it charge for 3-4 hours or 5 hours and then note the readings as we are more interested in finding out if Voltage across the terminals is crossing over 13.7 Volts or 14 Volts.

[irfan44]

Excellent thread indeed. I've been following it since long & checking my circuits to b in prospect.
2day I just want to verify few things
1. My ups battery water used to drop very slightly over a month& all was ok but now the water is dropping rapidly & I see black color on inside of battery caps.
I thought the ups is over charging & tested it with multimeter & found it going beyond 14v.
I opened up the cover ( it a desi 1) & found nothing adjustable on the Digipower mainboard but a rheostat which stated CHARGE CUT. so. I turned it a little towards Minus sign & now it stops charging at 14v.

1. I recently checked the output on ups & it gives 257v with a tube light turned on. Is it safe. As I can't find any adjuster on board to reduce it

2. Can u elaborate why laptop & cell chargers go bad on ups. Is it safe at 257v

[mag88]

Excellent thread indeed. I've been following it since long & checking my circuits to b in prospect.2day I just want to verify few things1. My ups battery water used to drop very slightly over a month& all was ok but now the water is dropping rapidly & I see black color on inside of battery caps.I thought the ups is over charging & tested it with multimeter & found it going beyond 14v.I opened up the cover ( it a desi 1) & found nothing adjustable on the Digipower mainboard but a rheostat which stated CHARGE CUT. so. I turned it a little towards Minus sign & now it stops charging at 14v.2. I recently checked the output on ups & it gives 257v with a tube light turned on. Is it safe. As I can't find any adjuster on board to reduce it3. Can u elaborate why laptop & cell chargers go bad on ups. Is it safe at 257v

1. Good you saved your life of battery.2. Dont worry much most of the equipment are rated 240 +- 15 %. Its been time since i refreshed theory of thyristors and voltage regulation but in lay-man's words these UPS output is load dependent and i believe they are designed to output 220V (@50Hz as per pak grid rating) at 80% of rated load. May be the guy at the corner UPS shop can visit you and have a look if the UPS in hand output is adjustable . Get it tuned to 220V at typical load you use it for. should not cost you more then anay janay ka kharcha aur chae biscuit.3. Actually the capacitors get damaged due to 3 step square wave of the UPS, non sinoside output. For extended period of usage pure sin wave UPS are available but they costs in multiples of this basic UPS. Hence the desi UPS damages Fan capacitors(replace every year), Mobile Chargers(cheap thing to replaces) and electronic equipment (eg TV 2-3 year , so if you dont want this to happen then dont use it on Desi UPS etc)

[irfan44]

^ thnx a lot bro.

[Khurrammoon]

SO far, the reading which you have quoted are within aspect. But why do you turn off the UPS after two hours of charging. Let it charge for 3-4 hours or 5 hours and then note the readings as we are more interested in finding out if Voltage across the terminals is crossing over 13.7 Volts or 14 Volts.

Talha Bhai I extensively checked the inverter charging. Used 23 Watts load for 1 and half hours and inverter took 3 and half hours to charge the battery and automatically terminated the charging.
After half an hour of charging reading was 13.66V.
After one and half hour reading was 13.68V and 13.69V (.68-9) kept on fluctuating after 3 hours and 25 minutes I was taking the readings then I noticed that 13.69 V and 13.68V was still fluctuating. After 2 minutes 13.69V and 13.70V started to fluctuate and then inverter stopped the charging automatically.
Well from these readings it is clear that once inverter gets to figure of 13.68V(and this voltage is achieved within an hour) and from there onwards 13.69V takes a lot of time. The only problem is that it takes so long for the battery to charge.
23Watts load for one and half hours and then inverter took 3 and half hours to complete the charging and then terminated the charge, that is a long long time. This would only increase the electricity bill for no reason. Some times inverter takes 5 to 7 hours to complete the charging but readings do not exceed 13.70V.

[talhawaleed]

Excellent thread indeed. I've been following it since long & checking my circuits to b in prospect.
2day I just want to verify few things
1. My ups battery water used to drop very slightly over a month& all was ok but now the water is dropping rapidly & I see black color on inside of battery caps.
I thought the ups is over charging & tested it with multimeter & found it going beyond 14v.
I opened up the cover ( it a desi 1) & found nothing adjustable on the Digipower mainboard but a rheostat which stated CHARGE CUT. so. I turned it a little towards Minus sign & now it stops charging at 14v.

2. I recently checked the output on ups & it gives 257v with a tube light turned on. Is it safe. As I can't find any adjuster on board to reduce it

3. Can u elaborate why laptop & cell chargers go bad on ups. Is it safe at 257v

257 Volts with tube lights turned on is perfectly safe. With no load on UPS while in back up mode the Voltage should be around 260 Volts. Your laptop, computers and mobile chargers are safe under the current configurations. Normally, with passage of time as batteries will be drained then this Voltage of 257 Volts will drop until it till reach 220 Volts or even below. Voltage at this time on batteries will be around 10.5 Volts (batteries) roughly and UPS should shut down once Voltage drops below 220 Volts with Voltage on batteries around 10.3 Volts roughly. Till 270 Volts, nothing will happen to your computer but it will restart once Voltage will drop below 220 Volts and can also blow away few charges. So you should keep an eye on Voltage such that on backup mode it should not fall below 220 Volts. You should turn off your PC once Voltage is around 225 Volts.
If somehow UPS could have able to maintain the Voltage around 220 Volts even batteries being strong or weak then that was the best possible scenario but we know since this does not happen so that?s why I advice this above configurations.

And if you can install the Voltmeter as shown in the picture on UPS line then I think it will become very easy for you to keep an eye on the performance of UPS.

[talhawaleed]

Talha Bhai I extensively checked the inverter charging. Used 23 Watts load for 1 and half hours and inverter took 3 and half hours to charge the battery and automatically terminated the charging.
After half an hour of charging reading was 13.66V.
After one and half hour reading was 13.68V and 13.69V (.68-9) kept on fluctuating after 3 hours and 25 minutes I was taking the readings then I noticed that 13.69 V and 13.68V was still fluctuating. After 2 minutes 13.69V and 13.70V started to fluctuate and then inverter stopped the charging automatically.
Well from these readings it is clear that once inverter gets to figure of 13.68V(and this voltage is achieved within an hour) and from there onwards 13.69V takes a lot of time. The only problem is that it takes so long for the battery to charge.
23Watts load for one and half hours and then inverter took 3 and half hours to complete the charging and then terminated the charge, that is a long long time. This would only increase the electricity bill for no reason. Some times inverter takes 5 to 7 hours to complete the charging but readings do not exceed 13.70V.

See, your UPS manufacturer manual says that that UPS should cut off charging once Voltage hit 13.7 Volts so it is doing its Job. It does not matter if it is taking 3 hours to charge the battery or 7 hours as Voltage is not exceeding the set limit on batteries.
Few good UPS charges the batteries in three stages, that in first stage it may charge @ 10 A( Example), in second stage it may charge @ 5 Amperes (Example) and in third stage it may charge @ 3 Ampere(Example) so that?s why it is taking longer to charge the batteries. You can test this using an AMP-METER.

Gravity on your electrolyte says that batteries are in good condition so I don?t know why you are getting worried. You electricity bills will never exceed if UPS cuts off the charging at 13.7Volts.

Last of all, I said and I am repeating it. Voltage on batteries will drop till around 12.4 Volts once UPS has stop the charging so it is normal and has nothing to do about ?that it is not keeping the charge?. It will start to charge it again(Good UPS) once this will automatically reach around 12.2 Volts, 12.3Volts etc.

[irfan44]

^thats a dandy gadget up there. is it available?

[Khurrammoon]

See, your UPS manufacturer manual says that that UPS should cut off charging once Voltage hit 13.7 Volts so it is doing its Job. It does not matter if it is taking 3 hours to charge the battery or 7 hours as Voltage is not exceeding the set limit on batteries.
Few good UPS charges the batteries in three stages, that in first stage it may charge @ 10 A( Example), in second stage it may charge @ 5 Amperes (Example) and in third stage it may charge @ 3 Ampere(Example) so that?s why it is taking longer to charge the batteries. You can test this using an AMP-METER.

Gravity on your electrolyte says that batteries are in good condition so I don?t know why you are getting worried. You electricity bills will never exceed if UPS cuts off the charging at 13.7Volts.

Last of all, I said and I am repeating it. Voltage on batteries will drop till around 12.4 Volts once UPS has stop the charging so it is normal and has nothing to do about ?that it is not keeping the charge?. It will start to charge it again(Good UPS) once this will automatically reach around 12.2 Volts, 12.3Volts etc.

Talhai Bahi I am only worried because for last 7 months inverter performed better especially during the summer season when there was a lot of load on it and power outages are so much frequent. Now with the start of winter season inverter takes so many hours to charge the battery. One month is remaining on Warranty period of my inverter and I just wanted to know if there is a problem with the inverter then I can claim that warranty before it expires now, you are telling me that inverter is ok. Then there must be some problem with the batteries. If inverter charges the battery for so long then surely electricity bill will automatically exceed. Another thing that I wanted to ask that may be this issue is because of winter season and temperature drop.

[talhawaleed]

Talhai Bahi I am only worried because for last 7 months inverter performed better especially during the summer season when there was a lot of load on it and power outages are so much frequent. Now with the start of winter season inverter takes so many hours to charge the battery. One month is remaining on Warranty period of my inverter and I just wanted to know if there is a problem with the inverter then I can claim that warranty before it expires now, you are telling me that inverter is ok. Then there must be some problem with the batteries. If inverter charges the battery for so long then surely electricity bill will automatically exceed. Another thing that I wanted to ask that may be this issue is because of winter season and temperature drop.

This can be due to batteries getting old and not having a proper electrolyte in them. I can?t say anything till the time you done measure the charging rate using Amp-Meter and report it to me in following forms
After one hour of charging: Amperes
After two hours of charging: Amperes
After three hours of charging: Amperes
After four hours of charging: Amperes and Voltage on batteries.
How can I comment on thing, whereas the data provided is in-complete? Data which you provided seems ok but fault might be with the charging rate.
Lets suppose, Even if the charging rate is ok then only reason left would be internal chemistry with the battery which changes with time that?s why maybe its taking little longer to charge.

[talhawaleed]

^thats a dandy gadget up there. is it available?

Available from College Road Rawalpindi for around 600 -700 Rs.Very Useful, as it instantly tells us the state of charge left in UPS.

[NakedTruth]

What is the name of this device?. Which company?. Let me find it in Lahore.

BTW, How long have you been using it?. Is it reliable?. Will it work continuously, 24/7?.

[Malik238]

Assalam o Alaikum everyone! This is one of the best threads on PW. Anyone who is going to try this experiment first time especially mixing of acid and water it is advised to gradually mix acid in water and not water in acid. This will make the procedure go safe

[NakedTruth]

Bump!.

[talhawaleed]

What is the name of this device?. Which company?. Let me find it in Lahore.

BTW, How long have you been using it?. Is it reliable?. Will it work continuously, 24/7?.

As the name suggest, this is panel mount voltmeter, you can easily find it from College Road, Rawalpindi or any good electronic shop in your city.

[talhawaleed]

Assalam o Alaikum everyone! This is one of the best threads on PW. Anyone who is going to try this experiment first time especially mixing of acid and water it is advised to gradually mix acid in water and not water in acid. This will make the procedure go safe

thanks for Appreciating

[Hashim11]

AOA! Very informative thread started. I have a problem, 4 months ago I repaired the UPS(Homage) from their service centre, and now I observed that it's cutoff voltage is 12v. Before repairing it's cutoff value was 15 or 16v. Should I complain them or it is fine to keep using? Does it effect the backup time of the battery?

[talhawaleed]

AOA! Very informative thread started. I have a problem, 4 months ago I repaired the UPS(Homage) from their service centre, and now I observed that it's cutoff voltage is 12v. Before repairing it's cutoff value was 15 or 16v. Should I complain them or it is fine to keep using? Does it effect the backup time of the battery?

How can you be ok with this. Before was wrong and right now is also wrong. Get it adjusted to 14 volts.

[Hashim11]

How can you be ok with this. Before was wrong and right now is also wrong. Get it adjusted to 14 volts.

How can I be okay that's why i asked for help. Thankx I will do it asap.