Problem with my UPS charging + draining

Dear All,

I have been reading this forum from quit some time as silent reader but this is my first post. I don't know exactly if it belongs here or not but still want help from you gurus here..

Yesterday i got changed kit + module of my desi 700 watts ups. Module is 75NF75 (2000 watts 10+10) and kit is IB-4 (IC-105). both are from Imran Brothers hall road lahore.

Now there are 2 main problems I am facing...

1- Charging amps were set to 12 amps but I checked (UNI-T 203) after couple of seconds they fall to 0 and then again start rising till 12... then after 4-5 seconds they fall back to 0 and then after 2 seconds again start to rise till11-12. This happens 5-6 times and then amps settle to 7-8 .

2- Even battery is full when light goes out and ups is running only 1-2 energy savers of 23 watts, battery immediately drains up to 9.8 volts and keeps there... if I remove all load from ups even then it keeps till 10.0 - 10.5 volts. While my old kit was keeping voltage till 11.5 - 11.8 volts even under load of lights and fan and gave backup upto 4 hours..

Please help me whats wrong and how to check if module or kit is culprit.. do I need to change kit or module and replace with other one from Imran Brothers???

Please move this post to proper thread if it doesn't belong here...

THanks a lot in advance...

check your Lead acid Battery. i think your discharged battery was not charged for long time.

There seems to be an error. do you mind sharing all details for review?

Thank you guys for considering my problem... I am new in electronics but have huge urge to understand whats going behind the scenes...

Dear Masud58 bro, battery was not charged only 2-3 days when previous 150N circuit was blown... even with that circuit battery was never below 11v in 1-2 hours.....

Dear SunnySkyguy, as I installed both kit+module new hence sharing what is in my knowledge. please guide which type of further info you want so I can post here...

isn't it strange that under no load at all inverter stays at 9.5v...apms draw on black battery lead is 4 amps and on red lead is 6 amps.... is it normal?

Thanks.

SunnySkyguy said:

There seems to be an error. do you mind sharing all details for review?

Click to expand...

Details like the schematic, parts list and layout with readings and test points for starters.

You need to set variables present on board. Set batt-full preset to trip relay at 14.2V. Set charging current near 16-Amps for 150AH battery. It is normal that charging current falls initially and rise again. This also happens when battery terminal are loose or wrong tap of transformer is used. When charging current is detected above the set point, PWM falls to zero and then gradually ramps up again.
When battery is 70%-80% charged, charging current is automatically reduced to a lower level. You are observing this behaviour.

SunnySkyguy said:

Details like the schematic, parts list and layout with readings and test points for starters.

Click to expand...

I don't have schematic but the image of the kit which I am attaching. I am just a user of this kit having some issues so know not much and need guidance regarding issue and its testing.

Thanks

ALERTLINKS said:

This also happens when battery terminal are loose or wrong tap of transformer is used. When charging current is detected above the set point, PWM falls to zero and then gradually ramps up again.

Click to expand...

Please shed some light on transformer taps settings... and what to do with them... here I am attaching pic of transformer...


Battery cut off is already set at 14.4v battery low set at 9.3 as it suddenly drops to 10v as soon as ups is on inverter mode. whithout load apms on black wire are 1.7 and on red 3.6.

Thanks

Everything seems OK. You need to charge your battery for extended period to regain its capacity. Set Batt_full to maximum for time being and let the battery be charged until it bubbles extensively and become slightly warm.

Do you have an iron core transformer which is rated for 50/60 Hz being used for PWM frequencies on the primary with high Eddy Current losses? Proper transformer design and selection is necessary for inverter.

ALERTLINKS said:

Everything seems OK. You need to charge your battery for extended period to regain its capacity. Set Batt_full to maximum for time being and let the battery be charged until it bubbles extensively and become slightly warm.

Click to expand...

Yesterday checked SG of all cells with hydrometer and found that the SG of first cell near +ve terminal was in red area while all other cells are in green area ...

battery charges up to 14.4v and then charging disconnects. it then slowly lowers till 11 v when again ups charges it...
battery is Phoenix XP165 and has passed 3 seasons... do you think flush will work well or I should try extended charging???
tried extended charging but voltage reaches 15v... is it ok?

Thanks.

SunnySkyguy said:

Do you have an iron core transformer which is rated for 50/60 Hz being used for PWM frequencies on the primary with high Eddy Current losses? Proper transformer design and selection is necessary for inverter.

Click to expand...

Yes sir, its iron core transformer and worked well for 3 seasons.. as mentioned in my previous post it looks battery is culprit as it has passed 3 seasons...

Thanks

Guys I need to learn about the details of how ups works internally... I know it in broad spectrum but need to understand which part on kit does what like the mosfets, how is biasing voltage generated, how small kit transformer works .. how to test different things in case ups not working well... how to test and replace kit parts.... and lots more...

can anyone guide me with some good tutorial or such stuff? I searched net but found only basic things which I already know.
Where can i learn it in Lahore or online...

I think I know almost what a street ups guy knows

Thanks

By the way something like this guys wants to do

https://www.edaboard.com/threads/181839/