Morning

If  utility voltage is supposed to be 230v, at what voltage will the inverter switch to batteries?

My Axpert 5kva, 4 x 260ah batteries, often goes click, click and I hear the fan starting up, but, by the time I get to the DB it has stopped

I just happened now, when I was closeby and the utility was on 198v, fan going, jumped to 218v and click, click, fan goes off

Tried to Google a couple of phrases but found nothing 

Thanks

William

looks like possibly there are two voltage ranges (at least for Axpert inverters which the Mecer should be a version of)

"Appliance setting": 90-280VAC

"UPS setting": 170-280VAC

I am on UPS setting, maybe the dip was below 170v, it takes a fraction of a second to switch over then a a few seconds to switch back

Bit above my pay grade but it even if the voltage remained within limits i think it would also start inverting (i.e. running from the batteries) if the AC frequency is not within a certain range. Under and over voltage is probably more likely.

12 hours ago, William-Mc said:

I just happened now, when I was closeby and the utility was on 198v, fan going, jumped to 218v and click, click, fan goes off

If that is the case, its better to allow it to disconnect and reconnect. Grid at 198v will burn a fridge/freezer compressor fast. Are you sure its the true grid voltage, dont you perhaps have a loose connection somewhere on your supply wiring to the inverter?

 

Not sure about the Axperts, but I know some Inverters don't rely on only the RMS voltage to decide if the grid has failed, because it takes at least one full cycle to calculate the RMS, and if the grid fails near the end of one cycle, the RMS for that cycle could still be within spec. so it would take more than a cycle to realise that the grid has failed. So one way that some inverters do it is to calculate the magnitude of the voltage vector, which on a single phase supply takes a quarter cycle (so only 5ms at 50Hz), which I would guess may be what the Axperts do in UPS mode. This does mean however that if the grid voltage waveform is quite distorted and the RMS is already fairly low, it could easily trigger the low voltage disconnect based on this method, and as @Jaco de Jongh mentioned, it's probably better for your appliances anyway.