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

[Lucky_star]

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?

 

[janitha]

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?

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.

 

[Lucky_star]

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.

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

 

[gopi_vbboy]

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.....

 

[Rollercoaster]

@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.

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

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

 

[paroh]

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

 

[spikygv]

@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. .

 

[Rollercoaster]

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

 

[acewin]

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.

 

[Lucky_star]

RC, will be trying this soon

 

[dheeraj_kumar]

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

 

[Lucky_star]

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

 

[janitha]

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

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/-

 

[infra_red_dude]

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

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.

 

[Lucky_star]

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.

 

[Rollercoaster]

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.

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?

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

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?

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.

 

[Lucky_star]

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.

 

[infra_red_dude]

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

 

[Lucky_star]

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.

 

[Rollercoaster]

Sounds abt right.. too bad tho..

Hope u get to try it again soon.