APC 1500 battery back-up

Take the battery out and see if it does the same thing when you turn it on.

mosfet

remove the load fom the ups and restart the ups. if the ups alarms again then the problem is in the inverter.

just check that you are not overloading the ups or make sure that the ups output is not connected to the input of the ups in most of such cases almost all light indicators start blinking

The Overload relay may be faulty. Replace the overload relay. Althernatively turn in the UPS to an expert since there is life power in the circuits.

Without knowing which light is flashing I can only guess. From my experience and assuming it is the battery light that is lit and NOT the overload light, it can be one of two things, one is your battery is near the end of its life and needs to be replaced, and the other is that your battery is improperly connected.

To confirm if your battery needs to be replaced or not, you can run a self test. Ensure that the battery has had time to fully charge (and that it is definitely correctly connected), and then turn off the UPS, and turn it back on. It will automatically run a self test.

if the light stays lit, you need to order new batteries. One source is here: http://www.refurbups.com/APC-Back-UPS-RS-900-BR900-Replacement-Batteries

If it IS the overload light that is lit, you simply have too much equipment attached to the UPS, more than the inverter can handle. Try removing some equipment until it turns off.

Check all MOSFET.

it is main provlam to your electrick

Internal fault.

Hi,

Plz check MOSFET which working in inverter section.