Monitoring Tesla wall charger options

1

Hello all,

I just had a Tesla gen 3 wall charger installed and am waiting on delivery. The electrician installed a two-pole 60A circuit breaker in the panel and I am currently monitoring both wires. The charger is configured to be maxed out at 48A but I am using two 100A CTs. The circuit draws very little power in idle mode but the best I can tell is that both wires do not have the same draw. The most I have seen so far is 12watts on one leg and 6watts on the other.

My question for those that are monitoring a wall charger is how have you setup the CTs? I will not be able to verify my setup until I take delivery, which is a moving target at this time, so I am hoping someone has already gone down this road and has a accurate setup.

My options are:

  1. Use two CTs and two ports on the base (There are two open ports)
  2. Use two CTs and a headphone splitter (48A max on the circuit and 100A CTs monitoring each leg)
  3. Use one CT with reversed wires (I had the electrician leave a loop but it is really tight in the box and it uses 6 gauge wire)
  4. One CT and double it in the software (each leg might be the same at higher amp draws but it is not at low as in mA right now so probably not accurate)

Any feedback would be greatly appreciated.

Alan

2

Is it two-wire or three-wire? i.e. is there a [usually white] neutral wire in addition to the two wires connected to the breaker?

3

It is a 3 wire.

4

option 2 if you want to capture the 6W difference, which might actually just be noise/calibration differences.

A quick search indicates that even Tesla chargers do NOT use the neutral. You do NEED the neutral to be there for some outlets (like for a range). So I would go with option 4, one CT and double it. With a 100A CT, you are measuring noise at even 12W.

5

Thanks for the feedback. Just got word of delivery next week so should have some solid data soon.

6

Update. Did my first charge today. @frogmore, you are correct and it looks like the circuits can be doubled.

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