Desi UPS vs China Power Inverters

Hey, lots of question going on in my mind... here is another one from the bucket ... Can I run my Super Asia room air cooler RAC-450 P on UPS?????? !!!!!!!

Regarding homage it charges at the rate of 4amp when the voltage is normal & 2-3 amp when voltage is low, the charger with the specs 12V 10Amp or 13v 15Amp will work with it without any trouble in this much load shedding.

actually I wanted to know if it is safe to keep external charger connected when inverter is also charging via its internal charger. Can connecting external charger create issues with internal homage charger?

[quote=“nasirjavaid, post:23, topic:17404”]

actually I wanted to know if it is safe to keep external charger connected when inverter is also charging via its internal charger. Can connecting external charger create issues with internal homage charger?

[/quote]

If external charger is constant voltage type with current limit, then it is perfectly safe to keep it connected. Make sure the charging voltage of the external charger is little higher than the charging voltage of the UPS otherwise it will not charge at all.

Absolutely right.. Actually I want to implement it first with my Sogo rechargeable fan :) ...... Its internal charging circuit is pathetic just like some ups charging circuits and needs 10-15 hours to give 1-2 hour backup. I only charges at 7.5V 0.2 - 0.3 Amp. So I bought a transformer of 9V 1A, which after connecting bridge rectifier gives 8.5V 0.8A (8.5 is i think safe voltage for 6v 4.5A battery). So I wish to install it in fan as 2hours of charging with it gave me 1.4 hrs backup :)

Next I will go for UPS charger and do the same....Thanks for your input bro.

[quote=“nasirjavaid, post:21, topic:17404”]

Hey, lots of question going on in my mind… here is another one from the bucket … Can I run my Super Asia room air cooler RAC-450 P on UPS??? !!!

[/quote]

Yes, you can if it is within the capacity of UPS. Air coolers do not consume power more than 400 watts.

Yesterday I asked one desi ups maker that if I connect 2 batteries in series what will happen to their votage? answer was obvious... voltage will get doubled... interesting part is that when i asked him what will happen to current... and he said that will double too ...:D

[quote=“nasirjavaid, post:27, topic:17404”]

Yesterday I asked one desi ups maker that if I connect 2 batteries in series what will happen to their votage? answer was obvious… voltage will get doubled… interesting part is that when i asked him what will happen to current… and he said that will double too … :D

[/quote]

Capacity also gets doubled.

This parallel and series philosophy is valid for circuitry dealing with flowing current and potential difference.

[quote=“nasirjavaid, post:27, topic:17404”]

Yesterday I asked one desi ups maker that if I connect 2 batteries in series what will happen to their votage? answer was obvious… voltage will get doubled… interesting part is that when i asked him what will happen to current… and he said that will double too …:D
[/quote][quote=“blogger, post:28, topic:17404”]
Capacity i.e. AH also gets doubled.
[/quote]

For a series circuit, voltage will get doubled but AH capacity will remain same e.g. If 02 batteries of 12V/100AH are connected in series, it will become 24V/100AH

^^ Do not tell me physics. I know it. Theory says it.

Capacity is doubled in both the cases, series and parallel, practically. (we have 1+1=2 reservoirs)

I hope, being an engineer, you have much more experience with such things. :)

Ijaz is right. If you connect 2 12V 100AH batteries in parallel then you get 12V 200AH but when you connect them in series you get 24V 100AH because current remains same in series.

I was told that I can run only the fan of air cooler but not the water pump on UPS.... is it true?

[quote=“blogger, post:30, topic:17404”]

^^ Do not tell me physics. I know it. Theory says it.

[/quote]

Is there any harm if you correct me or I correct you ? Discussion is the main objective of the forum. If I shouldn’t tell you something, why are you telling other people something ?

BTW: I was not telling you specifically but to other people who might develop a wrong concept due to your statement. If you are not interested in knowing something, you can simply ignore it. :)

[quote=“blogger, post:30, topic:17404”]
Capacity is doubled in both the cases, series and parallel, practically. (we have 1+1=2 reservoirs)
[/quote]

If you talk in terms of Watt-Hours, yes the capacity is doubled but AH is not doubled rather voltage is doubled.

[quote=“blogger, post:30, topic:17404”]
I hope, being an engineer, you have much more experience with such things. :)
[/quote]

And I never mind if I learn something even from kid.

I respect everyone’s opinion but when misconceptions are stated as facts - I will definitely point it out.

[quote=“nasirjavaid, post:31, topic:17404”]

I was told that I can run only the fan of air cooler but not the water pump on UPS… is it true?
[/quote]

You can measure the current drawn by the air cooler while both the fan and pump are running and there is enough water as well (always measure the worst conditions parameters). This will tell you if you can use the air cooler on UPS or not.

[quote=", post:32, topic:17404"]

If you talk in terms of Watt-Hours, yes the capacity is doubled but AH is not doubled rather voltage is doubled.

[/quote]

:rolleyes:

Indeed. The flowing current is not doubled. It is a mere fact. (corrected my post)

But ‘‘stored’’ charge inside batteries is doubled.

The only thing which astounds me is that when I hear from an experienced personnel that ‘‘no capacity is not doubled in series connection’’. What? When charge storing capacity is doubled and when backup provided is also increased to x2 which can be observed practically, then why do they say this! :mellow:

^ It's all due to various technical terms / terminology in everyday use. The charge storage capacity of the battery bank will increase if you add more batteries but capacity (or AH) of individual battery will remain same.

Yesterday the UPS maker installed my desi UPS at my home. There is some tweaking needed and he will visit today again to check it as it was late yesterday and light was out for 2 hours. I want to know couple of things

1- When light goes and UPS switches from main to UPS, there is a little delay of like 1/2 second and energy saver seems link it is turned off and then on quickly. Is this an adjustment problem or the kit is faulty and needs to be replaced?

2- When on UPS, it gives out almost 300 V instead of 220-240 volts. He said that even ups output is more volts than normal but they are not harmful. Is this true?

3- When light resumes there is a delay of 4-6 seconds before the ups switches to mains and sequence is as below.

i) UPS light is lit and mains LED is also lit.

ii) After 4-6 seconds UPS led switches off and Battery Full LED turns on for 1 second.

iii) And then Battery Full LED turns off and Charge led turns on.

Is this behavior OK?

Please guys waiting for your answer as I want to know this before he comes at 12PM to check the UPS and I should have some clue so that he can not dodge me by saying this is normal.

Thanks in advance guys.

[quote=“nasirjavaid, post:36, topic:17404”]

1- When light goes and UPS switches from main to UPS, there is a little delay of like 1/2 second and energy saver seems link it is turned off and then on quickly. Is this an adjustment problem or the kit is faulty and needs to be replaced?
[/quote]

This is switchover time of the UPS and you can’t adjust it.

[quote=“nasirjavaid, post:36, topic:17404”]
2- When on UPS, it gives out almost 300 V instead of 220-240 volts. He said that even ups output is more volts than normal but they are not harmful. Is this true?
[/quote]

Mostly the UPS output is either a square wave or a modified sine wave and most of the AC voltmeters (except some very expensive and lab grade types) are calibrated on sine wave, thus you see 300V on your typical AC voltmeter. If you use a True RMS voltmeter, you will get different reading.

[quote=“nasirjavaid, post:36, topic:17404”]
3- When light resumes there is a delay of 4-6 seconds before the ups switches to mains and sequence is as below.

i) UPS light is lit and mains LED is also lit.

ii) After 4-6 seconds UPS led switches off and Battery Full LED turns on for 1 second.

iii) And then Battery Full LED turns off and Charge led turns on.

Is this behavior OK?

[/quote]

Yes, this 4-6 seconds delay is normal and this is to avoid the situation where AC mains comes back and immediately goes away.

[quote=", post:37, topic:17404"]

This is switchover time of the UPS and you can’t adjust it.

Mostly the UPS output is either a square wave or a modified sine wave and most of the AC voltmeters (except some very expensive and lab grade types) are calibrated on sine wave, thus you see 300V on your typical AC voltmeter. If you use a True RMS voltmeter, you will get different reading.

[/quote]

Thanks Ijaz,

1- I have seen many desi ups that do not represent that ‘blink of the eye’ behavior and switch to UPS so cleanly that you never feel light has gone. A UPS made by same person to my friend works in this manner.

If it is not adjustable then it means he will need to replace the kit?

2- So it means that this voltage is ok and i should not bother with it? as i have a very good digital multi-meter (UNI-T UT50C), which the ups guy was admiring, and it shows 300v normal and 285 on 1 fan + 1 saver.

digital-multimeter-735.jpg

[quote=“nasirjavaid, post:38, topic:17404”]

1- I have seen many desi ups that do not represent that ‘blink of the eye’ behavior and switch to UPS so cleanly that you never feel light has gone. A UPS made by same person to my friend works in this manner.

If it is not adjustable then it means he will need to replace the kit?

[/quote]

This delay might be due to a slow relay, slow response time of AC present detection circuit, or some kind of software delay (if there is a microcontroller on board), if you think necessary, you can ask them to change the kit or the UPS.

[quote=“nasirjavaid, post:38, topic:17404”]
2- So it means that this voltage is ok and i should not bother with it? as i have a very good digital multi-meter (UNI-T UT50C), which the ups guy was admiring, and it shows 300v normal and 285 on 1 fan + 1 saver.
[/quote]

I can not confirm if the value of 300V is really OK, but as you have seen this UPS does not have any feedback to control the output voltage thus the voltage decreases with increasing load (AKA poor or no load regulation.)

I think they set the output voltage at full or 80% load and there is no feedback resulting a higher output voltage at no-load or light loads.

300 V is quite abnormal. It will result in blowing fan capacitors and burning energy savers one after the other.