Min Return Runtime not having effect

[Bartolo]

Min Return Runtime not having effect

[BillP · Accepted solution]

Hi,

Sorry for the inconvenience. If the load is less than 4.5 amps at the time of shutdown the available runtime will not calculated properly and the UPS will power on when AC is restored immediately as you are seeing. To allow the UPS to charge enough to provide the proper protection add an additional delay. Enter a figure into Power On Delay the allow the batteries to be charged before AC is restored to the outlet group/s. 

Another option is to have the load shutdown prior to required runtime of 14 minutes. That way when the UPS restores AC there will be enough runtime to sustain the load. 

[Bartolo]

Thank you, that explains it. I'll add Power On Delay or increase Low Battery Duration to leave more capacity.

How much charge time would it require to add 15 minutes of runtime for around 500-600 W load?

[BillP]

Hi,

That is tough to say because the charge time is based on the age of the batteries and the environment. I would add a 20 minute delay and adjust after testing. 

[Bartolo]

Thanks, I'll do both earlier shutdown and add some charging time.