Charging Slowed - Poor grid power quality possible

[Falcon73]

Well I got a fun message this morning after a couple hours of charging it 36 amps. See below.

The circuit is rated for all the way up to 50 but I don't push it beyond 40 due to the 80% rule.

I've not had any problems doing closer to 40 before but yeah.

Is Tesla smart enough to coordinate with Edison to limit my charging at home because we're at risk of rolling blackouts? Or is this some other issue?

If the latter I guess I'll just try 32 amps or something. I am charging through an adapter on a chargepoint charger that's hooked up to the wall via the usual 14-50 outlet. Maybe the adapter can't handle that much but I doubt it.

 

[mxnym]

The charging speed is usually limited due to voltage drop. Is your 14-50 plug somewhat difficult to pull out of the outlet, or does it slide out with ease? If it's easy, the outlet is likely worn and/or cheap, and the voltage sag that would trigger this could be coming from the heat generated by that poor connection. If not, it's also feasible that the grid power quality is actually poor at this time.

 

[Falcon73]

Well, I had an electrician buddy over today and he thinks it might be the half inch conduit that the three 8 gauge wires are in (2 hots and a neutral). The "ground" is a cheat by using the metal conduit.

He said the conduit was pretty warm as well, after I had been charging for a little while (under an hour). It might need to be changed to 3/4". It's also a pretty long run from the panel. Perhaps 70', which might be a bit long for 8 gauge. I find it odd that the panel is on the other side of the house vs the garage, but maybe that was the thing in the 60s? Speaking of which, the wiring is all copper now (since 2010) and the 240 outlets were probably copper from the beginning. The garage has been super hot lately as well. So, I'm guessing it's on my end and that other BEV's haven't been as picky as the MX (that includes the MYLR but we only had that briefly in the middle of winter).

 

[mxnym]

Well, I had an electrician buddy over today and he thinks it might be the half inch conduit that the three 8 gauge wires are in (2 hots and a neutral). The "ground" is a cheat by using the metal conduit.

He said the conduit was pretty warm as well, after I had been charging for a little while (under an hour). It might need to be changed to 3/4". It's also a pretty long run from the panel. Perhaps 70', which might be a bit long for 8 gauge. I find it odd that the panel is on the other side of the house vs the garage, but maybe that was the thing in the 60s? Speaking of which, the wiring is all copper now (since 2010) and the 240 outlets were probably copper from the beginning. The garage has been super hot lately as well. So, I'm guessing it's on my end and that other BEV's haven't been as picky as the MX (that includes the MYLR but we only had that briefly in the middle of winter).

Heat may be a factor, but I don't believe it's the temperature triggering your warning; I'm fairly confident it's the voltage. If using the conduit ground is causing too much resistance, that might possibly explain it. If you are certain the wiring is the issue (seems likely based on hat you've described), the neutral isn't used, so if you want to try to be cheap, you could ask the electrician about switching from 14-50 to 6-50 so the existing neutral wire can be changed over to a ground wire. You'd have to get an outlet and an adapter instead of getting new wire (not sure how that would compare to new wire and additional labor for installing it), but depending on whether the run is actually too long or not, that could be a viable solution. OTOH, cost aside, if you have other EVs, then that gets more expensive or less viable (depending on whether or not they also have 6-50 adapters). It may also be possible to run a wire to ground (you know, the earth just below) near that outlet just for that outlet, but I wouldn't be surprised if code frowns heavily on that suggestion.

 

[Falcon73]

I am using a TMC now (finally got it - actually more than 1). It's limited to 32A anyway on 240 and so far it hasn't barked at me about the grid. 32A is enough.

 

[mxnym]

I am using a TMC now (finally got it - actually more than 1). It's limited to 32A anyway on 240 and so far it hasn't barked at me about the grid. 32A is enough.

That is interesting. Is the environment cooler now? What is the voltage shown when charging at 32A?

 

[Falcon73]

Yes it's a bit cooler now but was still very warm. We are out of town for another week so we will see what happens when we get back.

It was showing 230V last I looked so a bit better.

 

[EbS-P]

No current flows on the ground. Your neutral is tied or bonded to the the ground at your main panel. You can look up the fill capacity of the conduit. It’s a code thing, it can only be so full.

I would check other voltages in the house. You you have similar voltage on both hot legs. Like both are about 113v or is one much higher than the other. Ask a neighbor if you can check their voltages. Outside plugs would be fine.

I would have the electrician check all the lugs on all the breakers are torqued appropriately .

Evan