I’ve added a new circuit for an electric car charger but I haven’t yet got a new CT. I’m wondering however if I need one.
Can I use the output function to measure my one remaining circuit?
Would it just be the Main minus the clamped circuits? Or am I seriously underthinking this?
If all other branch circuits are clamped I would think the difference is all you need (assuming solar is properly accounted). Due to small errors you might see the difference go slightly negative. You should know what the expected power draw is, give it a try, see if difference goes from zero to expected when you charge. I think many of us do a difference from little used and small draw circuits so as just not to have so many CT’s (and thus more Iotawatts).
Thanks for the reply.
Try as I might I can’t figure out what to do with the solar. Essentially the number I am looking for is about 7-7.5k.
So by your status display, you are using a total of 8,062 Watts (mains + solar) and your circuit total as in “UsedNow” is 390. That indicates about 7,672 Watts is going someplace else. If that’s about what you think the car charger is using, should be fine. If not, there’s something else going on.
My impulse would be to remove something less significant to the charger, like the Lights. The lights, and anything else unmeasured, could then be calculated with the output and represent only a small part of your total usage.
sorry if this double-posts… I did an email reply the first time.
So something like this but without the lights?
The result with the charger off looks about right but doesn’t reconcile to 0 exactly (should it?):
Exactly is a relative term here. I add your circuits up to 4,685 vs 4,693 mains + solar. That’s a difference of 8 Watts or 0.17%. I don’t know what you have for Current Transformers, but the best generally available are +/- 0.5% and most of the China ones like SCT013 are a generous +/- 1%. So I think you are well within the margin of error.
