I just posted this in the Questions section in reply to a topic about PVOutput accuracy, but i think it’s worth raising here too. I’ve also been discussing this problem on the TMC Tesla Energy forum. My Powerwall 2 was installed in July and my old mechanical meter generally recorded Zero peak power demand per day, except, rarely, when the battery ran out of charge. The Powerwall usually supplies all the Peak demand. I have dual tariff, Peak and night rates.
I had a new Smart meter installed on 30th October, with a remote display showing current power consumption to 10W resolution, and immediately noticed that there was a fairly constant demand of 60-100W. That doesn’t sound very much, but it’s 1.5kWh per day, over 500kWh Peak tariff per year = >;£150 - 20% of my electricity bill!
We have done fairly extensive testing (by turning everything off in sequence) and it appears that the Smart Meter is recording accurately and that the Powerwall itself is responsible for the demand. I am in discussion with Tesla Energy at present. They told me that the Spec was for a maximum daily demand of 500Wh so mine is way out of spec. I’ve just sent the requested 7 days of meter readings to them and am waiting with baited breath for the response!
One thing occurs to me - PVOutput grid flow shows continuous very small demands and exports, usually <10W. I understand that this is the Gateway calibrating things. Tesla also told me that the inverter and internal systems sometimes draws power from the grid. Why it can’t use it’s own power I’m not sure since it will operate off grid with no problem. However, the Smart Meter only records Import. It can theoretically record Export as well but that hasn’t been activated on my meter. In any case, it would be impossible to separate out the Solar export, which we get paid for, (assumed 50%) and Powerwall checking export, which we wouldn’t get paid for. So the meter may be recording the import side of the Gateway balancing algorithm stuff and not the return export.
Maybe the old meter was not sufficiently sensitive to record very low power demand although it should surely have recorded a couple of light bulb’s worth of power?
Has anyone else noticed excessive Powerwall grid demand while the battery should be supplying everything?