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Wall Connector Current Fluctuating

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TL;DR: When using Wall Connectors in load-sharing, will the current fluctuate 2A when only one car is plugged in?

I recently installed two Gen 2 Wall Connectors with load-sharing in my garage to prepare for my wife's Model Y along with charging for my Model S.
Strangest thing happens when charging with either connector: Every few minutes, the current to dips from 40A to 38A and then goes back to 40A after 10-60 seconds (example charge from TeslaFi attached). At first, I thought it was my wiring so I double-checked every connection, replaced both 14-50 outlets, and even re-ran a power wire to no avail (thought it may have had a broken connector during install). It doesn't do it every time, which is even more frustrating.

The last test that I just finished with was:
1. Turn off breaker
2. Disconnect WC2 (slave)
3. Power on
4. Charged car with WC1 (master) and got full 40A
5. Reconnected WC2 (NEMA 14-50 pigtail, I'm not that crazy)
6. Observed car current drop to 38A and bounce back to 40A
7. Continued dropping to 38A and bouncing to 40A
8. Switched comm wires and made the former slave the master
9 Same results

Is this normal behavior for WCs on load-sharing?
 

Attachments

  • 2A Fluctuation .png
    2A Fluctuation .png
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I can see a 2A variation on our 3 charging while the X is plugged in but not charging. Not something I've noticed before.

One possibility is that you're hitting the power limit before the current limit. Our voltage is often above 250V, which leads to the current being reduced a few amps in order to stay within the max power limit.
 
One possibility is that you're hitting the power limit before the current limit. Our voltage is often above 250V, which leads to the current being reduced a few amps in order to stay within the max power limit.

That's a good thought! I just went back and checked and power in the charge listed never got above 240v, just hung around 237v for most of the charge.

I'm wondering if it could be the charger using some current at idle and this causes the other charger to reduce power? I can't imagine it is using that much power....
 
This may be related to an issue some people have recently been having where the car continues to slowly trickle charge while plugged in even after it has reached its charge limit. What has fixed it for most is to cycle the scheduled charging on and off again in the cars. You might try that.

Here's the threads I recall offhand talking about this issue: Wall Charger continues to charge when complete

Those with Gen 3 WC, do your lights work like manual states?

Thanks for the advice! During my tests, I had the car set to 50% limit and increased it just for the test pretty much. I'll cycle the scheduled charging and see how it fairs.
 
Sorry to bring this thread back up, but if someone else is wondering about this, I found the culprit:
This happens occasionally when you have two or more wall connectors in load-sharing.

I'm not sure why it does this, but since they load-balance in 2A increments, I suspected this and disconnected the communication wire temporarily.
Immediately, the 2A fluctuations stopped and I got a solid 40A. When I connected the communication wire again to the other Wall Connector, it started going down to 38A back to 40A again.

Now we know! :)