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use an UPS as Voltage Stabilizer

I wonder how effective are UPS at providing Voltage regulation (without switching to battery). Most of them claim to have AVR inbuilt. Would they negate the need of a separate stabilizer or not?

bhvm (author) 1 year ago
you both are correct.
there are 3 types.
1 standby- switches to battery when input is past tolerance
2 line interactive- multiple tap method that provides some level of voltage stabilizing, but switched to battery out of tolerance
3 double conversion- least efficient method. input is used to charge battery and output is always from the inverter.


I'm thinking, would an old not_so_nice battery ups provide avr, provided it's an line interactive version. or what if battery is entirely dead.
GDXN bhvm1 year ago
The 1 is only overvoltage and not AVR, but is basically correct.

Yes, if they UPS has AVR it can be used as AVR even with the battery dead, but it need a little mod to trick it if the battery is dead, depending on the model even a big condensator and a resistor can do the trick. In my case I modded a UPS to use a external car battery ( I obtained 15 times the original autonomy).
bhvm (author)  GDXN1 year ago
I don't know but the order of replies / posts is messed up the website is acting up a lot these days. now I can't see where I type :-(. here is a repaste and gdxn, what about my questions 2 and 3 ?
I'm using an modded ups (600va model )as full time inverter with a truck battery. (160ah )
it's good enough for my small office. I have added added heatsinks and fans. made a custom housing for the same. however I still could not defeat the' no load shutdown'function. any insights mate?

coming to my initial plan, I was thinking to remove the battery and use large condenser in place. do you think it will provide enough protection for my fridge? what value of capacitor will you recommend mate?
GDXN bhvm1 year ago
About the 2, the extra power draw is the same as a SAI or a AVS, most of the time negligible. And for the 3... You are going no need a very big condenser (various farad for seconds of autonomy), I can't be sure of enough protection but i things that can be enough.

And for to defeat the no load... that depends on the model and what you want, one it can be an autostart system but if it's only used as AVR there are other possibilities as to mod the firmware in some model o bypass the load detection.
bhvm (author)  GDXN1 year ago
I want to defeat it entirely. model first choice is apc back ups es 500va.
it shall start when supplied ac power. and shall also continue on battery mode as long as battery allow.
thanks.
bhvm (author) 1 year ago
okay! I tried powering up an ups (500vA ) without battery by connecting to mains voltage. I did not budget. it's not as easy as I had thought..... folks help me!!
GDXN bhvm1 year ago
UPS model or better the schema? there are ones that can be powered without battery (they tend to scream but the AVR works) and ones that need the battery (I have from both types)..
bhvm (author)  GDXN1 year ago
models-
apc back ups-es 500va(300w )
apc back ups C 500va
numeric 600va .
microtek 800va (2x 12v 7ah battery ) line interactive model.
bhvm (author) 1 year ago
I'm using an modded ups (600va model )as full time inverter with a truck battery. (160ah )
it's good enough for my small office. I have added added heatsinks and fans. made a custom housing for the same. however I still could not defeat the' no load shutdown'function. any insights mate?

coming to my initial plan, I was thinking to remove the battery and use large condenser in place. do you think it will provide enough protection for my fridge? what value of capacitor will you recommend mate?
depends on how they're doing the AVR...most of them use the battery to accomplish AVR by simply running the device that's plugged in to the UPS off of the battery the whole time so that it's always got constant voltage. some of the fancier units do active AVR with actual hardware instead of the batteries.
This is wrong, I found 3 types of UPS that claim AVR built in:

The most common uses a multi-tap autotransformer and depending of the input voltage it select the correct tap, this type in found in the interactive line UPS ( actually this type is a offline UPS with AVR capabilities).

The ones that go ac-battery-ac, is the online UPS and is the most expensive type.

The mechanical type,in this type is electric motor-transmission-generator, actually it has a flywheel and a combustion motor, only used for very high power.


But for most applications an AVR and a voltage stabilizer is the same, but not always and that depend more one the line conditions, you can view a AVR as a high end voltage stabilizer for a lot off applications, there are some specific condition that made that not to be always true. For example and AVR has a high range of input voltage wen a AVS can have a higher filtering capabilities, there are models that combine both capabilities.

PD. The AVS efficiency goes from <1% to 95% depending on the load and model, actually in the typical range of use (20%~90% off load) depending off the model it has a efficiency better than 80%, in practice tend to be better than 90% but some cheap and/or old models are in the 80-90% range.
bhvm (author)  GDXN1 year ago
I wonder, how would it be to use an UPS with Dead battery as "just" avr or Spike protection. I have loads of these lying around my house and they use 12v, 7AH batteries that are dead.
1)Would they provide SOME level of protection or the battery thing is compulsary?
2) What would be the extra power draw in such case?
3) How about putting a capacitor bank in the place of battery? That would clear the transients , I suppose.
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