AC500 power draw when grid connected and energised

What I’ve observed is regardless of the UPS setting on the AC500 whenever the grid connection is energised the unit seems to draw additional power (~60w) whether it needs it or not (i.e. battery at 100%). Does anyone know why? Is this a bug?

This is particularly annoying for PV Priority mode where the grid should effectively be turned off when the SOC is above the configured value and only draw power when it falls below the SOC% (to top up the battery). Since this excess draw is always there it negates much of the benefit of using PV in the first place (60w x 24h = 1.44kwh).

My workaround for now is to use a timer switch on the grid input so it only energises once a day for an hour to top up the battery but this seems silly since PV priority should be doing this out of the box.

For additional detail this topic came up in another thread here: Power consumption of the AC300 - #22 by MichaelSDE but it was a bit of a thread hijack so splitting it out might be better.

@hwh57 - This depends on how your measuring the power coming from the grid to your AC500. What every your using to capture the power usage, 60W, is it a measurement of “Active” power or “Reactive” power?

I know from my system I always seen “Reactive” power coming from my grid to my AC500, but reactive power is not used by the system and is returned to the source (grid). If it’s “Active” power, which is used by your load, then that’s a problem…

Do you know which type your metric your capturing?


AC300 internal electronics have quite a significant idle power drain, and internal electronics always run off battery power even when there is good utility power available. So even if connected to AC it will always have charge/discharge cycles.

1 Like

@hwh57 We are very sorry for the inconvenience.
The AC500 idle power consumption data is measured without input, if there is input is the value will indeed be higher.

Have a look in the ‘customised UPS’ settings and make sure the settings won’t override your PV mode setting

I had a similar issue with the AC300. In PV priority mode when the unit reached 100% charge it would start to draw from the grid

Yes the idle power draw is well documented for AC500/AC300:

Not sure about active v reactive, I was just measuring power as reported by utility draw.

I think @Rods might be onto something. Even though PV Priority mode was selected and SOC% set I noticed on occasions the battery would charge to 100%. On checking customized mode it had “Grid Charge Status” and “Time Control Status” both enabled. I’ve disabled these and will see if it happens again … could somehow these settings get activated even if that mode isn’t selected?