Connecting MY Smart UPS to an Inverter

[Anonymous user]

So I have connected my BR1500G to a Square Wave Output Inverter and the UPS is switching to main and battery whenever the Inverter is going to Backup mode but I was told by APC Service team that if I use a pure sinewave output inverter it will just work fine

So will it work fine if I get a pure sine wave output inverter?

[BillP]

Hi Sandipan,

The UPS is designed to monitor the quality of the sine-wave it is being provided and switch to battery power when deemed necessary. The Square-wave output of the Inverter will definitely not be accepted by the UPS. As long as the inverter you are using outputs a Pure Sine-wave with RMS voltage within the correct 120vac/60hz range and minimal harmonic distortion, the UPS should accept the power.

Secret Squirrel

[Terry_Kennedy_apc · Accepted solution]

One other thing to consider when powering a UPS via an inverter or generator is that when the UPS powers on, it will pull current from the inverter / generator which may cause the inverter / generator to reduce its voltage and /or frequency to compensate for the load. This can cause the UPS to transfer to battery due to "unacceptable input power". That lets the inverter / generator recover, and when the UPS senses that it will transfer off battery and the cycle will repeat over and over. This generally means that you need a substantially higher wattage inverter / generator than you would think, based on the UPS nameplate rating.

I think there used to be a knowledge base article on this, but that was decades ago and those have been re-organized multiple times since then.

Edit: I found it (or something similar) - FA158891. It looks like FA158842 and FA157508 may also apply.