HA Glow vs Shelly EM - varied results at high load

I’d had issues off and on for months where HA Glow would work near perfectly and align with my power providers reports, then out of the blue would spike like mad. I’d mucked with edge vs pulse, altering pulse interval settings etc. Tweaked the diode potentiometer again which I think may have got out of kilter and its reading fine again (for now)

I’d also ordered a Shelly EM (with 120A clamp) out of sheer frustration and I set this up today. I put HA glow vs Shelly EM watts used into the UI to monitor them together, they were pretty damn close and I’d suspect would average out over the day to be the same or close to it (HA at top, Shelly bottom)


However I noticed when high power kicked in (pool pump, spa filter and heater on plus various other high consumers) that HA glow went up whereas the Shelly EM wattage stayed a lot lower. I confirmed with a manual clamp meter on the power in and it showed about 32A (x 230V about 7.5kW)

The HA glow 7.5kW at top is correct, Shelly way off.

Any ideas?

Here is glow and uni graphs overlaid, visible differences especially the spikes

Oh NVM, user error :slight_smile:

Turns out there was a smaller separate feed coming in I’m guessing for the HWC had to clamp that too. Readings in line now