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olalekan

increasing backup time of ups

Pls sir it possible to change/adapt a more bigger battery on ready made ups  

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  1. 1. Pls sir it possible to change/adapt a more bigger battery on ready made ups

    • creating seperate charger
      1
    • increasing size of the casing
      1


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Hi, I have done the similar mod some three years back. What I have done is
1. I removed inbuilt battery, 7AH 12V sealed Lead Acid, in that place I installed a 5A 0-18V transformer and a battery change control circuit.
2. I installed a standard 120AH tubular battery outside ups.
3. Connected it to the board in the same place as that of the standard battery.
4. Removed the 1-2W wire resistor (which will be in the charging circuit) to isolate the inbuilt battery charging circuit.

Its working fine for me since then, now i am using that 600VA ups for my home, with my mother watching TV when there is no power in the area for 4-5 hours. ;)

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Dear Sir,
  Thanks for answering/sheding light on my question .Please sir I don't know whether with your arrangement the UPS we still be able to perform it funtion ;that is to provide UNINTERUPTIBLE power to the PC,because this is  8)the main important function of the UPS.
  Also what is the important/usefull of the installed tranformer in place of the regular battery,please I will be happy if more light can be shed on complete adaptation of this UPS to the desire long backing time one.Thanking you in anticipation for your valueable response.

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Dear Sir,
Thanks for answering/sheding light on my question .Please sir I don't know whether with your arrangement the UPS we still be able to perform it funtion ;that is to provide UNINTERUPTIBLE power to the PC,because this is 8)the main important function of the UPS.
Also what is the important/usefull of the installed tranformer in place of the regular battery,please I will be happy if more light can be shed on complete adaptation of this UPS to the desire long backing time one.Thanking you in anticipation for your valueable response.


Yes, it does, as i mentioned in my post, my UPS is giving me a uninterrupted supply to my whole house for 3-4 hours. :)

About transformer, you need to chanrge the external battery somehow right?, and your inbuilt charger can't carry it off, so you need to have separate charger. Instead of having a charger and UPS separately i Installed a charging

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Dear Nura,
  Thanks for your concern on the issue ,Please are you trying to say that the mosfet in 600VA would not be able to carry a load of about 400VA for about 4-5hours and the SMPS you are talking about, is it the ready made type that normally comes with laptop PCs or i  have to built it locally ---I do'nt have any SMPS sch.circuit to built for this . I don't know if you can help with one  .Thanks very much for spending you precious time to attend to this issue.I wish you good luck in your all endouvour in this life and hereafter

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Dear MVADU,
  am very gratefull on reading your response on the the issue .Please Sir I don't know if it is possible for you to send me the sch.diagram on the charger.I think with this information from you I think I can succesfull adapt the UPS to a longer backing time.Please don't hessitate to give me any addition information that might be usefull to complete.THANKS

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hello mvadu!

i wonder how your 600VA UPS is powering your entire House at different Locations, i mean it can support only one PC + Printer etc, but not all fans ,TV, Light Points.

Don't go by UPS Printed ratings of 600VA, have you seen the UPS Trafo inside , how small it is , the Guage of Wire can handle only 10-12 Amps Max, the heat sinks for mosfets are also small, b'coz these small UPS are supposed to provide back-up for just 10 -15 minutes, if you run it for extended hours, then the heatsinks would be extremely HOT

it can supply power upto 150 watts, either a 21" Color TV or 2 Fans at full speed but not all appliances at the same time.

arun


Hi Arun,

In my house i have two sections of wiring, one runs all high power appliances like pump, refrigerator. Other line powers all low power devices like TV, FAN etc. I have connected my UPS to the second line. And I have told my mom to "NOT to use all of the appliances together" :) so we make sure that we don't overload the UPS.

I have seen the UPS tranformer, its MOSFETs and I am fully aware of their limitations. In my first post i forget to mention that other than said modifications I have installed a 80mm FAN in the ups for cooling purposes. It takes care of cooling the transformer while charging as well as MOSFETs (and their heat sinks) when UPS is running as a backup supply.

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Hi Olalekan,

It is difficult to  home brew  an SMPS Battery charger, unless you are fully experienced with Switching Supplies.

you can Purchase a readymade SMPS 12V, Battery charger kit and use it, it is worth the investment, than trafo charger.

as suggested by Mvadu you have to use a Cooling Fan, otherwise you can Kiss your UPS goodbye!

if your are intending to use this Modified UPs for things other than Computer, like fans, TV etc, there is very chance of Over Loading the UPS. limit your Load to 150 Watts only.

Secondly, does your UPS Support COLD Starting, if it does then no problem, but if it doesn't then there is no point in going for this modification.

Arun

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Dear Arun,Nura.....,
  am a bit in a fix corner, my main aim is to use the said modified UPS for backing up my computer when the mains fail and also to be able to continue working for atleast 2-3hrs after power outageand most ATX power pack are rated 400watts so I don't know if it will still work for it.also I don't realy know what you mean by cold starting and how can i know  a UPS that support  cold starting ?
  Please Sir,  don't be bored about my question it only show my level on the field pls just try to help me out .God wil surely reward every one of you .THANKS

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Hello Olalekan,

you've asked about "cold Starting", Let me explain: if you are using your PC which is connected to your present UPS and there is a Power Failure, the UPS continues to supply Power to your PC in Split Second changeover.

this is called Warm booting.

consider a situation when there is a Power Failure and you want to use your PC which was not ON till that moment and you switch on your UPS during Power Failure to Power your PC this is called COLD Start , this can be fatal, if your UPS doesn't Support COLD start feature.

during Cold Start, the PC draws Heavy Current

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Dear Arun,
  Thanks for your concern,I am now fully understand COLD STARTING.I have problem in  indentifying the resistor that link the charger circuit to the battery ,any time I suspect a resistor linking the battery to the charger as soon as  i disolder it ,it disconnect the UPS ,the UPS will not even start at all, am thinking what happen if the mosfet is also use in charging the battery can some one still be able to isolate it as you said?Am thinking of buying another UPS for this adaptation  but I don't know which one to buy .....having charging circuit that can be seperate without putting the whole ting off

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Dear Sasi,
  thanks for making your contribution to this issue,are you telling me that with APC UPS I don't need to remove any resistor to isolate the the charging circuit of the UPS.Does that mean I can justparallel a 150ah battery across the UPS SLA battery.
  The circuit braker you are talking of it 's theone use in ELECTRIC INSTALLATION in house WIRING??
Thanks once again and remain blessed.

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Dear Arun,
  Thanks you very much for this effort you have put forward to assist me may God reward you abundantly in case I have any problem along the line I will contact you through this mediun.
  THANKS AND REMAIN BLESSED

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Dear sasi,
    you said I should place a mcb with rating not more than half of the battery rating .Pls am not clear , which battery are you talking about ,is it the UPS BATTERY OR THE EXTERNAL ONE AM ADDING .And pls can you tell me the essence of the mcb .
  THANKS

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Yes, it does, as i mentioned in my post, my UPS is giving me a uninterrupted supply to my whole house for 3-4 hours. :)

About transformer, you need to chanrge the external battery somehow right?, and your inbuilt charger can't carry it off, so you need to have separate charger. Instead of having a charger and UPS separately i Installed a charging

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