APC SMART-UPS 750

[Anonymous user]

good day to everyone, I have encountered problem in my APC ups model Smart-UPS 750  (SUA750RMI2U). At first the "replace battery" LED is continuously blinking knowing that the battery needs replacement but due to my very hectic schedule I forgot to buy replacment batteries until one day  the UPS shutdown. I noticed that the UPS body is very hot, I switched on the UPS but after almost 4 hours the UPS shutdown again and the unit is very hot. I checked the batteries inside and noticed that the 2 batteries connected in series are very hot. The batteries voltage is 8 volts and 8.4 volts. Maybe the batteries do not accept charging anymore and maybe the reason why the battery became very hot resulting to UPS shutdown. I tried to switched on the UPS and disconnect the battery by means of pulling out the battery plug located at the rear part of ups. However, when I woke-up in the morning, I found the UPS not in operation (shutdown) but not hot. I cannot power-up the ups with the batteries are disconnected. As far as I know, once the UPS is already powered-up, it can still be useful even the batteries are disconnected, AM I CORRECT? I have no idea that my ups is still OK, maybe this is already defective due to previous shutdowns (very hot).  If I will replace the batteries, will it be back to normal operation?  I need assistance/advice from anybody knows well about this APC UPS. Waiting for your advice friends…Thank you and more power…. Junil

[BillP · Accepted solution]

Juil,

When the batteries are hot that indicates that they need to be replaced immediately. The UPS will run when the batteries have been removed i.e the batteries are how swappable however it will not power up after the batteries have been removed. So in your case the UPS will not power back up until you have installed replacement batteries.

Note: when the batteries get hot they can swell so before you purchase replacement batteries you should verify you can remove the old batteries from the UPS. In rare cases the batteries swell to the point that they cannot be removed and in those rare instances the UPS needs to be replaced.