!!!UPS Modding!!! + >>>Increase Backup time Manyfold<<< I have done it....

PART II

Changed Battery connecters and lengthened them. Attached big battery connectors
*img163.imageshack.us/img163/7248/image264vz.jpg

Testing the new LED with a 3.6v battery
*img230.imageshack.us/img230/3522/image336ig.jpg
*img230.imageshack.us/img230/6854/image352fl.jpg

Install FAN and LED
*img230.imageshack.us/img230/7356/image377co.jpg

PART III

Installed the FAN and LED(sorry not much visible)
*img230.imageshack.us/img230/2542/image383eg.jpg

Fire it up for the first time
*img230.imageshack.us/img230/5808/image402ke.jpg

Close up everything
*img230.imageshack.us/img230/1607/image424vl.jpg

Install the UPS, connect new battery(u can see the old batteries being put to good use as stand hehe)
*img163.imageshack.us/img163/1636/image447xp.jpg

Part IV

Finished
*img163.imageshack.us/img163/3159/image452di.jpg

So what do u guys think. if anyone wants to do it tell me . i will put the steps in detail here...

wow, a lot of hard work in there. How long does your system run on the higher rating battery? Compare the results.

I am wondering how long can a laptop last on such a mod, would be a cheaper alternative than a laptop battery or an inverter if you arent taking your laptop to places.

great mod mate but its to risky to try. u might burn ur ups

Did you check the results? How long your UPS can give backup, I mean did you test
it? And I want to know the duration (in hours or mins). If you are able to convert
10 min backup UPS to 3 hours or more. That's great work indeed. Post the results
here, so that all can see & appreciate.

Great work.

Tell us, what time it is taking to re-charge.

khansdream said:

Great work.

Tell us, what time it is taking to re-charge.

Click to expand...

He is using 150 AH battery and 10A charger and so theoretically it should take 15 hours when totally discharged. But let alone being totally discharged, never even let it fall below 10.5V. (This is assuming he uses a 12V battery)

Hey guys.. thanks for the interest..
havent tested for the max backup time yet but i put the battery in quite a bit charged and it ran for about 3 hours. i am expecting backup time of over 4 hours on a fully charged battery.

Basically it depends on consumption.
My PC is a AMD64 3000+ on A8N SLI Prem with 1gb ram, 3hdd, one dvdrom, one dvdrw. 5.1 speakers, 17inch viewsonic ultrabright crt monitor and the PSU is 500W.

Anyone with a LCD would probabely get backups of over 6 hours.

Also The battry i used is local made so it is not a full rated 150AH. Can say around 135AH. also i read about One Amp current via my multimeter for stand alone UPS Runnig. so it is pretty good.

I will post the final backup time tomo as i will charge the battery full tonight and leave the pc running in the morning.

Anyways the basic math is::
Suppose ur original UPS gives a backup of 10mins.
Usually UpS Battery is a 12v 7AH.(charging at 700ma)
Now suppose u replace it with a 12v 35A battery(the one in a maruti car)
so u should theoretically get 35/7*10 minutes... i.e 50 minutes
I have put in a 150A battery so my theoritical backup should be:
150/7*10 = 214.3 minutes

The formula can be like this:
New Backup time in minutes = Old backup time in Minutes multiplied by New battery capacity in AH divided by Old battery capacity in AH.

One thing to note here is that the old backtime should be the one u got when the ups was new(The battery was at full 7AH capacity)
another thing to note is that the load(PC and periferals) should be same for the above to be accurate.


@Sourabh
Dude if u put on a laptop it will run forever...hehe. A laptop uses very little power. need to know the power rating of the laptop adaptor to tell u the minimum backup time.

@gary4gar
To gain some u have to risk sum. The danger of UPS burning is less then the danger of the PERSON getting electrocuted while modding.
BTW this is the reason i put in a FAN (for cooling)
Otherwise alsi i have givin this a lot of thought. U should realise that a UPS has a inbuilt voltage stabiliser on the same transformer. so if the transformer can talk the load of the PC while stepping up/down then it can ofcourse take the load of the PC on battry mode(that is also without stepping up/down)

@khansdream
janitha is right about the charging time calculation. But i am not charging at a full 10A. I have brought a variable current charger and set it on 4A. Besides the light problem here is not that bad that i have to freq use the pc on long battery backup. Whenever needed i can turn up the charging current.

also abt the 10.5v thing. there is a thing about batteries(say 12v) called deep discharge(below 9.8v) and overcharge(above13.5v). whenever these thresholds are crossed there is a 20-30% damage to the power of the battery. that is why auto cut-off chargers are used. and that is why the UPS turns off before the battry is fully discharged. Anyways usually there are full 300 cycles for a battry before is starts to go down in capacity.

Great work & post for sure!

Man, a very gud modding. But still all this must be around 8k to 9k + risk factor.
We can get a fairly gud inverter in its place.

Will try this in a month or two and will definitely get in touch with u.

casanova said:

Man, a very gud modding. But still all this must be around 8k to 9k + risk factor.
We can get a fairly gud inverter in its place.

Will try this in a month or two and will definitely get in touch with u.

Click to expand...

come on dude... where did "8k to 9k" come from, as i said in the 1st post, total cost = battery+charger = 3200+650 = 3850 + misc electronics. Also inverters produce bad electricity(for PC) as PC requires Sine wave and Inverters give TPZi wave. sure, sine wave inverters are also available but they give lower backup(low efficiency) and cost more.


EDIT: here is a pic of the system running of UPS mode and the backup time finally...

The total time it reports is approx 3 and a half hours(running for 2.5hrs and 55mins remaning).
This was done with the system running on Sissandra BurnIN auto cycle and Monitor on maximum monitor brightness. So i am happy to say that at full load i get backup of 3.5 hours.
Probabily on normal usage it will be above 4.25 hours.(as it purely depends on usage it is hard to give a accurate value, like if i am surfing the net then it will be much longer then while i am playing games)

NOTE: It shows the LOAD Incorrect

*img197.imageshack.us/img197/5339/upsmonitor5hx.jpg

UPS around 2.5k
battery+charger=3850
misc electronics=made a wild guess to add to 8k to 9k.
And where do u fit the fan mate.

casanova said:

UPS around 2.5k
battery+charger=3850
misc electronics=made a wild guess to add to 8k to 9k.
And where do u fit the fan mate.

Click to expand...

UPS is already a must.. whether inverter or not. god help u if u dont use ur PC on a UPS.

And misc eletronics is just wires, LEDS, cooling fan... total less then 100rs

See the pictures above to see where u fit the fan.

i do use a ups but still its cost has to be taken into account. I cant find any pictures rollercoaster.

man there are approx 12-14 pics here...cant u see them?

see the source code or press quote on each post to see the image webaddress.

well UPS cost is not taken into account as it is a MOD. The basic idea was to increasing backup capacity. I never thought about the total cost. anyways which ever way u see it, it is cheaper this way and more efficient and safe for the comp

Alright seen them. Good creativity. Dont know what problem it is. Couldnt see the pics in opera nor in iexplorer.

thanks. ya i get that creativity comment a lot.

anyways here are a few updates...

I installed a new chargerit charges fast and has better auto cut-off circuit.
It was getting too hot so i installed a pIII fan inside it.
*img224.imageshack.us/img224/6049/image05qf.jpg

here is another look at my creativity. Installing switches is real boring and takes lot of space. besides it makes the front look bad. so i did something new.. I installed jumper pins and use jumbers as switches
*img224.imageshack.us/img224/9357/image13zo.jpg

here is where is got the pins from.It is the circuit plate of a CDROM. the one where the IDE cable connects.
Then i heated them and they went thru the plastic like knife thru butter. this is a very convenient method and WORKS!!!
*img221.imageshack.us/img221/5968/collage0uq.jpg


colage by picasa 2.

whoa , great post man.
Really commendable.
keep it up.

thanks man.... thatzcool.

anyways now i am looking fwd to do my PC MOD!!
havebeen thinking for a long time and i hope it will look greate too...

Wow man... really cool setup. You must have been really brave to do that. Although i am a electronic engg. student i would never dare to open my ups and do some modding

well that is what happens after u have completed a century of electric shocks. LOL

seriously. before i was a computer geek i was a electronic hobbiest.. i think from around class 9.

i have built some heavy duty electric circuits. like heavy duty stabilizer(5kva), a 100W inverter, two way talkey thru electrical wiring, multi volt adapters and stuff...

Rollercoaster said:

well that is what happens after u have completed a century of electric shocks. LOL

seriously. before i was a computer geek i was a electronic hobbiest.. i think from around class 9.

i have built some heavy duty electric circuits. like heavy duty stabilizer(5kva), a 100W inverter, two way talkey thru electrical wiring, multi volt adapters and stuff...

Click to expand...

Congratulations from a similar person who used to get electric shocks from Pre Degree times and even designed and published a circuit for giving high voltage shocks using a single pen torch cell and got it published in the now extinct "Electronic Hobbyist" and got Rs.20 royalty 30 years back.
Pl dont misunderstand, Just being nostalgic.
BTW, is the charger an SMPS type?
The battery, if it was a tubular one could have given you a much longer back up and lasted upto 10 years, but of course you preferred this one to reduce cost.
Keep it up and let it be an inspiration to others.

janitha said:

Congratulations from a similar person who used to get electric shocks from Pre Degree times and even designed and published a circuit for giving high voltage shocks using a single pen torch cell and got it published in the now extinct "Electronic Hobbyist" and got Rs.20 royalty 30 years back.
Pl dont misunderstand, Just being nostalgic.

Click to expand...

thanks man. that is cool. i never got anything published on hard paper ever...

janitha said:

BTW, is the charger an SMPS type?
The battery, if it was a tubular one could have given you a much longer back up and lasted upto 10 years, but of course you preferred this one to reduce cost.

Click to expand...

NO the charger is a simple transformer(with 8 intermediate taps to select current/voltage) in series with a 10A diode. for pulse charging which is best for these local battries.

i got 20mins extra backup with this new charger. becuause it does not use a full bridge rectifier but a single diode we get stronger pulses. they are bets for charging these local made battries.

i dont know much abt battries internals or structure but 3.5 hrs avg backup is quite enought for me.

aree yaar.. kya baat hai...
but i think this is too big for me to try.
i would really like to get in contact with u roller... i have sending u private message. please respong.

yes this mod is only for experienced people. and playing with high voltages is never easy but cool.

The results are amazing.

BTW i replaced teh local 150ah battry and put in a Exide power 180AH battry. Backup is up by 1.5 hrs.

The thing bad is that now in uttaranchal light problems are going low as the tehri Dam project has started production . So now no power faliures. i donno if i should eb happy or sad.

for the last week there has been power loss fro less then 1 min.

-----[posting after a long time]-----

hellgate said:

hi
wanted some help to inc my UPS backup time.
currently i own a Powercom 1kva ups which has 2 12v 7ah batteries inside and has provision for connecting 2 external batteries (in series).my q is if i connect 2 12 65ah abtteries in series externally will the UPS work without being damaged??also will the bateries be charged correctly.
if not then wats the highest capacity battery that i shall be able to connect externally??

Click to expand...

u need to consider-
1. charging current - you need find out if ur ups can provide sufficient charging current. cause if the internal charger is only able to produce the current req for the internal battries or a little more then large outside battries will take for ever to charge. but it does not have any -ve affect on the working of anything

2. backup time/temperature - a ups is designed to provide small backup time and as such has minimal or no ventilation. so if that is the case then refrane from attaching too big batteries. cause when running on battery power u have a chance of burn out due to over heating but this can be checked by feeling the temp of the ups by hand to see if it is getting too hot. if yes then u cant keep it running for too long otherwise no probs. my own personal expert test is to take a damp cloth and touch it on the transformer core metal for a few seconds then lift it up and check for steam. gotta be careful too.

in essence, the size of the battery has no harmful affect on a UPS except affects of temperature on prolonged use. that also due to poor ventilation design of UPSes for compactness.

65ah batteries should not be a problem. btw y dont u call/email the company support and ask then what charging current and what battery size ur ups can support.

in my mod i used a ups that is very poorly designed for ventilation so i installed a fan. u can try that too. works gr8

Nice Post! Rollercoaster...
Good that you brought it up
Will try out this in my UPS once the battery goes down...

@Rollercoaster thnx a lot for the help.

dont think i will try that! but it is nice of you to share your mod , lets learn a bit how things goes around...
it is too risky for just about anybody to try...maybe you should put up a warning ...not to be attempted if you have no background in electronics

waiting to see how u goin to mod your pc

Yes that's right. you need intimate knowledge with hobby electronics and a heart for a few electric shocks to be able to play around with mains electricity. And you have to be ready for the off chance that things may blow up.

But it is not that bad after u get over ur initial fear after all electronics is very logical. Now unless you are careless there is not much to be worried about. As all contact with the electronic components is done in a OFF state. In the ON state all you do is monitor. The only danger is our own fear.

Going on a date is probably more dangerous.

Quote
"Going on a date is probably more dangerous."

Awesome work man*gigasmilies.googlepages.com/41.gif

Wow Man this is the most innovative post i've ever seen at any forum.

Bravo Boy Bravo!

Though i won't try this at home coz in this part of delhi we always get full time power supply but i'm really impressed by your work.

Awesome work dude ...need some courage to get to do this mod ..can u write a simple mod to light up inside the computer cabinet to make it look like Anitbiotic Or peace, i think u are the right person to write a tut on this subject .

If u can write briefly abt the cautions to be taken i am willing to light up my cabinet , ther would be more intrested to follow ur tuts

Thx

Yes i can write a tutorial for LED lighting inside the cabinate if more people want it. Please post here or pm me.

btw thanks a lot guys. this was one of the more interesting projects i have done.

Good stuff, RC!

Superb mate...... this thing rocks

Rollercoaster said:

Yes i can write a tutorial for LED lighting inside the cabinate if more people want it. Please post here or pm me.

btw thanks a lot guys. this was one of the more interesting projects i have done.

Click to expand...

common dude , dont wait for people to wake up , once u post a thread u will get loads of thanks and replies , dont u think so ? so why wait for response ..i ve requested this in ups modding thread , hardly a few would have come accross my request ...Please do it , i havent seen a tutorial for this any where else.

Rollercoaster, need ur help now. I have a wipro 500 ups whose battery is almost dead. I want to use a 35 Ah battery. Can i wire it directly to replace the dead battery? Even if the charging current is in mA, can it charge this 35 Ah battery? If yes, approx how long will it take to charge? Using a multimeter between the ups's battery terminals with the ups in charging/on state should show the charging current, right?

Now, I have got another iball ups which needs some repairing. After repairing it, I want it to use it as a mini inverter just sufficient enough to run 2 tubes/cfl. For this too I want to use a 35 Ah battery. Is it feasible? Other than the overheating problems, are there any other problems associated with it like burning of components?

Lucky_star said:

Rollercoaster, need ur help now. I have a wipro 500 ups whose battery is almost dead. I want to use a 35 Ah battery. Can i wire it directly to replace the dead battery? Even if the charging current is in mA, can it charge this 35 Ah battery? If yes, approx how long will it take to charge? Using a multimeter between the ups's battery terminals with the ups in charging/on state should show the charging current, right?

Now, I have got another iball ups which needs some repairing. After repairing it, I want it to use it as a mini inverter just sufficient enough to run 2 tubes/cfl. For this too I want to use a 35 Ah battery. Is it feasible? Other than the overheating problems, are there any other problems associated with it like burning of components?

Click to expand...

Generally speaking, lead acid battery needs 1/10th of the AH capacity (in amperes) to be charged. So, it will need about 3.5 amperes and the UPS charger will never be able to charge it even if partly discharged. For measuring current, you can use multimeter or a cheap ammeter.

janitha said:

Generally speaking, lead acid battery needs 1/10th of the AH capacity (in amperes) to be charged. So, it will need about 3.5 amperes and the UPS charger will never be able to charge it even if partly discharged.

Click to expand...

Thanks for the info. So, I will need a charger.
I have got a digital multimeter.

he u just increased the Ampere-Hour of the battery....make sure the ratings matches the previous battery......don;t touch both the terminal by mistake when charged.......anyway good hardwork....keep it up.....

@Lucky

As said, yes you will need a charger. There is no other problem , except that you need to be sure of the original battery(s) voltage and the new one. they should be same. You cant use one 35ah 12v battery to replace a set of 2 x 12v small battries. that sort of thing. I am sure u know that already but I wanted to be sure.

Regarding charging, for such a small battrey (35AH) the supplied charger may work. The simplest thing to do is connect the battery and let it charge, periodically checking the voltage. If the voltage doesn't reach the full (~ 13.5V on charger) voltage within a nominal period of time or you think you are not getting the expected amount of backup time then you need a separate charger.

But you dont have to worry with this test as the maximum that can happen is ur battery will not get fully charged after it discharges. There is also no danger of deep-discharge as the UPS shuts off and the inbuilt charger's charging current would be enough for trickle-charge.

Same answer for ur second UPS. The only problem you may(will) have is , two CFLs are too low a load and the UPS would shut off automatically as for it that would be a no-load situation(like when the computer is switched off and power goes out). Nothing much u can do there unless u want to go deep-diving in electronics.

gopi_vbboy said:

don;t touch both the terminal by mistake when charged.

Click to expand...

That is an urban myth. A battery doesnt have enough voltage to give a shock. if u do get a shock then that is because of current leakage and bad earthing from elsewhere in the equipment. That too only happens if u r f...ing around with it when it is plugged in

Nice one. But any one other than Rollercoaster will go for this

@Rollercoster , gr8 tutorial .. how much did the exide battery cost u ? can you write a tutorial for making a inverter ? it'll be cool for hobby electronics dudes. .

No point in writing one. there are tons in magzines and the net. try googling and the electronics for you website

its pretty safe.
ANd you really need to put the battery through UPS into computer, you can never directly put the invertor because UPS major task is to provide constant power(not more or less)

gr8 moding rollercoaster, and I will say easy said than done. You are showing and making it loook easy but its not that quiet easy.

also this can be done 3 way(increases total power 3 foalds making it even more running)

bigger battery to an invertor and invertor output to UPS. the better the battery you choose the more the running.
He mostly has choosen a battery which is seriously more compatible and will work without any probs. As bigger batter will have probs I think with the setup just like that.

RC, will be trying this soon

Cool tutorial! good job, rollercoaster, I'm an electronics hobbyist too, but right now on probation I'm not for trying this out, though, I'll prefer lighting up my cabinet

The charging current for the ups with its own battery(CSB single 12v-7Ah, like you have) is .61 Ampere. Do you think this will be enough? Actually I have used a used and partially dead battery, but its still in working condition. It showed 12.4 V before connecting it to the UPS. After charging for about the half an hour, the multimeter shows 12.8 V. I think its charging.
Here is the setup.
*img368.imageshack.us/my.php?image=18102008113smallzw8.jpg*img368.imageshack.us/img368/6959/18102008113smallzw8.jpg
*img368.imageshack.us/img368/18102008113smallzw8.jpg/1/w360.png

Moreover, there is a small earthing like current on the top of the battery. I got a shock on touching there. Is it a problem? I think, the acid/dampness on the top is conducting the electricity.
When I switch off the mains, the ups is shutting down immediately with 1-2 seconds with the monitor off. Is it the due to the poor battery or is it like, the battery can't take the load?

Got another query. I have seen many icecream wallas in their trolleys having a tube lit inside during night. They use a single 35/32 Ah battey without any inverter circuits. How do they accomplish that?
UPDATE:
I kept the battery charging whole night and its still the same. When I switch off the mains and the UPS shifts to battery power(with the PC on), it just shuts off. Do I need a new battery?

*img368.imageshack.us/my.php?image=18102008113smallzw8.jpg

Lucky_star said:

The charging current for the ups with its own battery(CSB single 12v-7Ah, like you have) is .61 Ampere. Do you think this will be enough? Actually I have used a used and partially dead battery, but its still in working condition. It showed 12.4 V before connecting it to the UPS. After charging for about the half an hour, the multimeter shows 12.8 V. I think its charging.
Here is the setup.

Moreover, there is a small earthing like current on the top of the battery. I got a shock on touching there. Is it a problem? I think, the acid/dampness on the top is conducting the electricity.
When I switch off the mains, the ups is shutting down immediately with 1-2 seconds with the monitor off. Is it the due to the poor battery or is it like, the battery can't take the load?

Got another query. I have seen many icecream wallas in their trolleys having a tube lit inside during night. They use a single 35/32 Ah battey without any inverter circuits. How do they accomplish that?
UPDATE:
I kept the battery charging whole night and its still the same. When I switch off the mains and the UPS shifts to battery power(with the PC on), it just shuts off. Do I need a new battery?

*img368.imageshack.us/my.php?image=18102008113smallzw8.jpg

Click to expand...

The UPS charger will be able to trickle charge it. The shock you got must be from some leakage voltage from the UPS.
The ice cream tube light should be lit by using a small inverter consisting of a transistor, ferrite core transformer, resistors and a capacitor or two which is available for about Rs.100/-

Lucky_star said:

When I switch off the mains, the ups is shutting down immediately with 1-2 seconds with the monitor off. Is it the due to the poor battery or is it like, the battery can't take the load?

Got another query. I have seen many icecream wallas in their trolleys having a tube lit inside during night. They use a single 35/32 Ah battey without any inverter circuits. How do they accomplish that?
UPDATE:
I kept the battery charging whole night and its still the same. When I switch off the mains and the UPS shifts to battery power(with the PC on), it just shuts off. Do I need a new battery?

*img368.imageshack.us/my.php?image=18102008113smallzw8.jpg

Click to expand...

Looks like the battery is dead. Try to measure the rate of change of voltage during discharge. Also if your multimeter allows it, try to measure the discharge current. You will surely get to know if you need a new battery.

The ups is just providing .61 A current which is enough for charging the inbuilt 7 Ah battery. For this 35 Ah battery a minimum of 2 - 3.5 A charging current is required. So, as janitha said, the ups charger is just trickle charging it.
ir_dude, i had kept it in charging during the night. Today morning it showed 13.1 V. When the ups is switched on(with the mains off), the battery is draining fast. It came down to 12.8-12.4-12.1 within two minutes and switched off subsequently. Is it because the battery gone weak or the charging current isn't enough?
Although my multimeter has a 10 A measuring capacity, I connected it for a few seconds while discharging and it displayed 13.5 - 14 A. Removed it immediately for fear of burning the meter.

You battery may be the problem. If the ups cant take the load of just the monitor then probably your battery is gone. Put a multimeter and monitor the voltage from Before turned off to turned on(offload to onload). If the voltage drops below 11v immediately(onload) then ur battery is dead or not charged at all.

Example data:
[OK Battery]
My batt's standby V is 12.9(doesnt tell anything).
On Charging:13.1v(almost full)
On Load: 12.7v (almost full and if i keep the multimeter attached it drops by 0.01v every few minutes i.e getting slowly discharged. this rate increases for smaller batteries)
[Dead/Discharged battery]
Standby: 12.7
Charging(dead one): 13.4 (if Dead it will show fully charged very fast.)
Charging(discharged one): 12.1
OnLoad(dead/discharged): <10.5 - 11.5

And the 10% charging current part is not accurate in practicality. Most batteries are happily charged below 4% their rating. For eg. in a car the charging current (for 35ah) in nominally 1amp only . And the big-truck-batteries 150ah are normally charged at 4amps (not 15amps are u might think. u dont even get a 10+amp charger easily in market)

I would suggest you to get hold of a new battery. may be take the UPS and the multimeter to a battery wala and pay him like 10 bucks to use one of his batteries to test it. You can use ur car's battery. no need to unplug it,just dont get it too discharged or there will be more of the aforesaid 'probations'

Now, there are two things to test for.
1. On Load: Use a charged battery. atleast half way charged. may be try ur dad's car battery . If it works ok for some load then everything is fine. Which should happen if the battery is not dead/discharged
2. Charging: Worry abt that later. first get the stuff working offline, i.e without power, with a charged battery. If you are happy with the result then start checking the charging current/time.

Note: a battery's stand-alone voltage (like u said 12.4..12.8.. etc is never accurate) Even a dead battery will usually show 12.5 or so volts stand-alone.

Shock(Leakage current in this case) is because of poor/missing earthing in ur house/socket.

And dont call it shock.. it is just some tingling.

Lucky_star said:

Got another query. I have seen many icecream wallas in their trolleys having a tube lit inside during night. They use a single 35/32 Ah battey without any inverter circuits. How do they accomplish that?

Click to expand...

they use miniature ctk inverters. available at a lot of places and as DIY kits. Basically the emergency lights without their plastic bodies.

Lucky_star said:

UPDATE:
I kept the battery charging whole night and its still the same. When I switch off the mains and the UPS shifts to battery power(with the PC on), it just shuts off. Do I need a new battery?

Click to expand...

Very Probable. to confirm test using a different battery.

btw.. in that image, what kind of wires are you using to connect the external battery. Dont use the ones used in homes. that is for AC and causes a lot of resistance for DC. Use the thick (made of lot of think wires) that is used in inverters to connect the battery.

Given the battery for charging today. RC, those wires I have used are for testing purpose only. If this thing works out, I will make a complete setup.

If the battery is discharging that fast.. then thats the culprit! Just for testing purpose, you may use a car battery.

The battery is really weak. Spent 50 bucks unnecessarily on charging a dead battery. It was of a WagonR. While discharging the voltage is dropping to 11.7 from 12.6 and is decreasing very fast, which indicates that the battery is breathing its last.
So, I have to postpone this project till I get a new battery
Given the other Ups for repairing.

Sounds abt right.. too bad tho..

Hope u get to try it again soon.

Hi Rollercoaster,
I need some help, I have "powersafe" (*www.powersafeups.com/line-interactive-specs.html) line interactive 600 va ups 3 yrs old with 12V/7AH battery, battary needs replacement and hence I think I can try out this mod. I am planning to attach 135AH to 150AH battery to this ups. since the internal charger will not be of help to charge this battery I will also get a external charger. The problem I am facing is in locating a internal charging circuit on UPS and placing a switch to enable disable it: I have basic knowledge of electronics circuits, but not enough to locate/modify the charger circuit on the UPS. Hence i think if I just put 1 diode in parallel with resister on the wire going to battery +ve terminal (anode of diode towards the +ve terminal of the battery pack) it will permanently disable the charging of batteries with internal charger. diode and resister ratnig I am planning to use are 2.2ohm/15W resister and diode rated for 150 amps. The idea here is resister will limit current to batteries during charge and during load current will flow through diode.
Please guide me if I am correct and if there are any problems with my diode/resistor ratings or any other problems?

From experience and more research I have determined that you dont have to disable the internal charger. you can let it running as is.

It is like attaching two power sources in parallel. So ur internal charger will give relatively negligible current and wont matter at all.

Also, when the battery is fully charged with the external charger the internal will also shut off as soon as it determines the proper voltage has been achieved.

Regarding you diode/resister Idea, if i understand correctly may work but it is not required and might be overkill.

Remember to mod the UPS for ventilation and cooling(fan) or it may burn out on extended usage.

Thanks,
I have attached 120AH battery and use 6A external SMPS based charger. Added a fan and switch for cooling with some holes drilled for ventilation. My setup is working fine now. Not tested how long it will provide a backup. But it sure works for 50 minutes that I tested.
Thanks again for all the help and starting this thread.

cyberaddict said:

Thanks,
I have attached 120AH battery and use 6A external SMPS based charger. Added a fan and switch for cooling with some holes drilled for ventilation. My setup is working fine now. Not tested how long it will provide a backup. But it sure works for 50 minutes that I tested.
Thanks again for all the help and starting this thread.

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It will be better to use 12/10 A charger since lead acid batteries are generally charged @ 1/10th of the capacity. Anyway pl keep us informed.

janitha said:

It will be better to use 12/10 A charger since lead acid batteries are generally charged @ 1/10th of the capacity. Anyway pl keep us informed.

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That is only a guideline. 6A is the standard in real world for 150AH and 10A chargers are not readily available.

hi
i am new here.i am thinking of modding my ups too (mine, too, is NUMERIC Digital 600 PLUS) . i have few suggestions.

Since this is a line interactive UPS we just have think about the battery.
what if we employ a switching circuit for connecting battery to the inverter section during LINE off using a comparator.

Also i am planning to make a 10A charger shown in www.sound.westhost.com for battery charging.although it lacks control circuit i think it wont make much of a problem since we have daily load shedding in my state.