Hi,
I am a student and I am a noob and new to this forum. I have basic knowledge about UPSs. I have a pure sine wave 1450 va exide ups wih 2 100ah sealed tubular lead-acid ups batteries (also from exide). I had it from 1 month and is working quite normal. Today when I came back from school at 5pm evening, mains power was gone and ups was on. My mom was there but she didnt know when the power went. After 1 hour, still there was no current. The things in the fridge were starting to spoil so I decided to connect it to the ups (its a tiny 47l fridge - only 200-300 watt). SO I connected it using an multi-plug cord extender. Suddenly ups went down for 1 sec and then the fridge started, after 4 secs fridge went off (maybe due to less voltage). I immediately ran to ups and checked the load %age (it has lcd display), and the load was 68%, and the ups fan suddenly started spinning in full speed ?!? (maybe overload or overheat). Then things went fine again. After 1-2 hours, the mains came again, and battery started charging. In between the fan would start spinning (which happens regularly).
Now coming to the strange thing:
Its been about 4-5 hours now, the ups is still displaying 'charging' !!!! And I can smell a bit of foul smell, so I immediately opened the windows.The battery doesnt feel hot. And its a costly premium one (about INR Rs. 13000 per battery). So im gettin scared whether it'll burst overnight !!?!?!!
So what do you think about it? Anything fishy guys? Please Help me out here!

 

The heat smell maybe silicon rectifier or mosfets, is there anything overheating, can you measure the voltage and current going into the battery?

 

Unless the manual tells you that it should charge faster, I personally wouldn't panic if it's not 100% charged after 4-5 hours, especially if the charge level is increasing and the batteries are not warm. Is there a away for you to check the charge level of the batteries? You can google the spec sheet for the batteries too and get the max charging voltage, then measure the batteries and if they are under the max voltage I wouldn't panic. After 12-24 hours if it's still charging, then I would start looking closer.

 

Most UPS units have pretty slow charging systems in them so a 4 - 5 hour or longer recharge time after being used fairly heavily would be understandable.