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Charging at home decreased to 46Amps

Starting just today, the charging goes from 64/64amps and 42mph to 47/64amps and 31 mph. I don’t get it.
There was a recent update and since that I’ve been charging somewhere else so I didn’t notice it until today. The charger is wired to TWO 80Amp breakers and has, for years, charged at 64Amps. It starts at 64/64Amps, but switches to 46-47/64Amps in a few minutes. I’ve powered down the car several times and have also reset the breakers on the charger. It also gives this stupid warning on the small screen, “Unable to charge. Disconnect cable and retry”
Any ideas?!
 

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48/48 would imply you are connected to a 60 amp circuit. 48/64 would imply that your circuit has an issue. You need to contact an electrician, and there is a good chance the terminals inside of your HPWC are melted because it wasn't installed properly. Improper installation modes include, but are not limited to:
  • Aluminum wiring, where additional expansion and contraction can lead to loose termination points
  • Wire not fully inserted into termination points
  • Termination points not tightened to appropriate torque
You should avoid using the HPWC and fall back to your mobile connector until this issue is resolved.
 
The dual 80amp breakers is to get the voltage to 240V. It has worked well with this configuration at 2 different homes and I have plugged the MX in every night without issue until yesterday. It starts out fine at 64/64 with ca. 240V and after a few minutes drops to 45-47/64. I’m not an electrician, but I think it is setup as 240V three-phase delta-connected.
 

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An electrician installed it… twice (2 different homes). And it has worked as advertised for 3 years… and I don’t understand why it would start at 64amps and then drop to 45-47amps — makes me think that there is something in the car…
Trying to get an answer from Tesla, but that is a little like a boiling oil enema… and I live 90 miles from a service center with the next appointment that I can go to in mid-November…
I’m just imagining this with every car an EV…
6E3401B9-4A63-47F5-B943-274C5AC8653F.jpeg
 
That’s what it does — stops at 45-47amps. But the weird thing is that it initially goes to 64amps and then drops after a few minutes. No amount of “retrying” will fix it. If I unplug it, go get milk, then plug it back in, it goes to 64/64amps only to drop back to 48amps after a bit. I used a dryer outlet visiting over the weekend and there was no issue there, but the charge rate was much lower — 20mph rate (I don’t recall the amperage). I’d go try it at the supercharger, but that’s 90 miles away.
Thanks for all the help!
 
So… just got off the phone with the Tesla Wall Charger people…
1. Wall charger is fine and (as best they can see) is installed properly — wall charger is not the issue.
2. The error codes point to a problem with the onboard chargers (as was described in this string — thanks GtiMart) and that is why the amps drop by 16amps. That is why I didn’t notice it when charging at a lower amperage. I shouldn’t have a problem at a supercharger (bypasses the onboard chargers).
3. I can still charge albeit at a lower amperage until I can get into the service center — seemed needlessly complicated to have more than one onboard charger, but now it seems Elon may have been prescient… again…

Thanks to everyone for their help and good advice… in spite of being a Tesla fan, I’m really crappy with electricity… I can apply it to the epicardium but, after a really bad experience with trailer heating tape and a straight pin, I’m moderately afraid of it… but that is a Reddington-like story that I don’t have enough characters for…
 
I had this happen to me one of the 3 boards in the charger started to fail and would cause weird issues charging. Tesla blamed the power company, soalr flares... and anything else they could. I had to take an amp probe to the circuit and monitor the drop while charging before they would replace the charger in my X. They claimed they were unable to reproduce at the service center which had 3 phase power and only 208 volts, not the 220 - 240 expected at home.

 
I had this happen to me one of the 3 boards in the charger started to fail and would cause weird issues charging. Tesla blamed the power company, soalr flares... and anything else they could. I had to take an amp probe to the circuit and monitor the drop while charging before they would replace the charger in my X. They claimed they were unable to reproduce at the service center which had 3 phase power and only 208 volts, not the 220 - 240 expected at home.

From what I've seen in other threads (or other forums, as the case may be), the problem with service centers diagnosing on-board charging problems is actually that they use a low amperage circuit. For instance, even if they connect this vehicle to a 48A service, it won't necessarily reproduce the problem, and then they will act like the problem must be somewhere else even though it was really their test that was inadequate.
 
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Fiver

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Apr 10, 2015
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The dual 80amp breakers is to get the voltage to 240V. It has worked well with this configuration at 2 different homes and I have plugged the MX in every night without issue until yesterday. It starts out fine at 64/64 with ca. 240V and after a few minutes drops to 45-47/64. I’m not an electrician, but I think it is setup as 240V three-phase delta-connected.
Just to correct your terminology, what you have there is not "dual" 80 amp breakers. You have a single 80amp, 240v breaker. Yes it kind of looks like two, and takes up two slots, but that single bar that shuts it off makes it one. It only looks like two as it's taking two 120v legs and putting them together (hence the double slot). This is a bit of a oversimplification but hopefully you know what I mean.

Hopefully this helps remove confusion if you have to describe the problem again.

As for your other issue, the 72 amp charger built in to your Model X has three boards inside. One for each phase. When all three are working, you have up to 72amp charging. One fails, you only can do up to 48amp charging... Two fail, you are limited to 24amp charging. They are very resilient though, you can start a charge session with all three working, and have 1 (or two) error out mid-charge, and you will still continue to charge, just at a reduced rate. The next charge they can all work again. Typically it's an overheating issue on one of the boards. This is almost certainly what is happening to you.

You can see the three phase boards in this video:
 
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Thanks so much!! As I said before, except for applying energy to the surface of an arrested heart, I freely admit that I am electrically illiterate! (As evidenced by my attempt to fix my trailer heating tape with an in-line thermostat when my pipes froze during finals in medical school — in an electrical epiphany I saw the problem immediately and jammed a straight pin across the plastic void… an imperceptible moment before it occurred to me that I might not be doing a smart thing… it is really hard to stand up in the crawl space under a mobile home…). Nonetheless, I do love my electric car and wouldn’t have anything else. Thank God there are people out there you guys to help me! In all seriousness, thank everyone very much!
 
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As for your other issue, the 72 amp charger built in to your Model X has three boards inside. One for each phase.
Electrical terminology can be very confusing. I don't know how to correctly say what you're trying to say, but I do know this is wrong for two reasons:
1) In the US, my 240V circuit using 2 legs (slots) in the panel is still single-phase (I used to think it was two phase, but that was wrong).
2) I can charge at 72 amps on the circuit described in (1), so the boards are not tied to (for) phases or legs.
 

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