Voltage readings innacurate

DIY
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1

I have 4 Victron 300Ah NG batteries in parallel controled by a 1000 amp NG BMS, these are connected to a cerbo GX. I started the first charge cycle with a connected Quattro 5k 230 volt inverter charger.

The voltage read out on the cerbo was 214v, I thought this was a low reading and perhaps the feed to the Van was undersized so measured the AC input terminals with a multimeter with the system charging - 233 volts. When the system went into Absorbtion mode the voltage reading on the cerbo went up to 233 volts.

My question is why is the readout low on the cerbo compared to a multimeter reading at the AC input to the Quattro ? If the feed to the van was undersized why was my reading with the multimeter with system charging normal at 233 volts.

Thanks

2

The quattro has a bad power factor when charging full blast and no ac loads present.

So you get waveform distortion, different instruments show different voltages as they have different algorithms to calculate the rms.

3

Thanks Ludo, so there is no harm running like this ?

4

I think so, as the voltage is far below what the quattro can manage and you have no loads connected.

5

So if I have a AC load going at the time it is charging the batteries it should correct the deficiencies
inherient with having a “bad power factor” ???

6

I use an electric heater :rofl: